From 1eb73d9fa63f7a1a42bb288d9c87f9912f0621df Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:04:25 +0200
Subject: [PATCH 001/159] Rename test case to better reflect the intent of the
 tests

---
 ...edLoaderTests.swift => LoadFeedFromRemoteUseCaseTests.swift} | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename EssentialFeed/EssentialFeedTests/Feed Api/{RemoteFeedLoaderTests.swift => LoadFeedFromRemoteUseCaseTests.swift} (99%)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Api/RemoteFeedLoaderTests.swift b/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift
similarity index 99%
rename from EssentialFeed/EssentialFeedTests/Feed Api/RemoteFeedLoaderTests.swift
rename to EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift
index 7a7fea1..a09fd5a 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Api/RemoteFeedLoaderTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift	
@@ -8,7 +8,7 @@
 import XCTest
 import EssentialFeed
 
-class RemoteFeedLoaderTests: XCTestCase {
+class LoadFeedFromRemoteUseCaseTests: XCTestCase {
     
     func test_init_doesNotRequestDataFromURL() {
         let (_, client) = makeSUT()

From 4bfac7acf50554d54f6b269503ff101288d61b6a Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:16:47 +0200
Subject: [PATCH 002/159] Does not delete cache upon LocalFeedLoader creation

---
 .../EssentialFeed.xcodeproj/project.pbxproj   | 12 +++++++++
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 26 +++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 0def712..dd3d805 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -11,6 +11,7 @@
 		080EDF0C21B6DAE800813479 /* FeedItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedItem.swift */; };
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
+		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -38,6 +39,7 @@
 		080EDF0B21B6DAE800813479 /* FeedItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedItem.swift; sourceTree = "<group>"; };
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
+		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -126,6 +128,7 @@
 		080EDEFE21B6DA7E00813479 /* EssentialFeedTests */ = {
 			isa = PBXGroup;
 			children = (
+				40B975392D9E7AD3009652B5 /* Feed Cache */,
 				40124C322CF8BDD5008BBDB6 /* Feed Api */,
 				080EDF0121B6DA7E00813479 /* Info.plist */,
 			);
@@ -141,6 +144,14 @@
 			path = "Feed Feature";
 			sourceTree = "<group>";
 		};
+		40B975392D9E7AD3009652B5 /* Feed Cache */ = {
+			isa = PBXGroup;
+			children = (
+				40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */,
+			);
+			path = "Feed Cache";
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXHeadersBuildPhase section */
@@ -298,6 +309,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
new file mode 100644
index 0000000..08471a9
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -0,0 +1,26 @@
+//
+//  CacheFeedUseCaseTests.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+
+import XCTest
+
+class LocalFeedLoader {
+    init(store: FeedStore) {
+        
+    }
+}
+class FeedStore {
+    var deleteCachedFeedCallCount = 0
+}
+
+class CacheFeedUseCaseTests: XCTestCase {
+    
+    func test_doesNotDeleteCacheUponCreation() {
+        let store = FeedStore()
+        let _ = LocalFeedLoader(store: store)
+        XCTAssertEqual(store.deleteCachedFeedCallCount, 0)
+    }
+}

From 11afe3bcafb73848c9e827f9edd24b00c1f6b2b8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:20:08 +0200
Subject: [PATCH 003/159] Save command requests cache deletioin

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 28 ++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 08471a9..8a8acaf 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -5,15 +5,25 @@
 //  Created by Cristian Felipe Patiño Rojas on 3/4/25.
 //
 
+import EssentialFeed
 import XCTest
 
 class LocalFeedLoader {
+    private let store: FeedStore
     init(store: FeedStore) {
-        
+        self.store = store
+    }
+    
+    func save(_ items: [FeedItem]) {
+        store.deleteCachedFeed()
     }
 }
 class FeedStore {
     var deleteCachedFeedCallCount = 0
+    
+    func deleteCachedFeed() {
+        deleteCachedFeedCallCount += 1
+    }
 }
 
 class CacheFeedUseCaseTests: XCTestCase {
@@ -23,4 +33,20 @@ class CacheFeedUseCaseTests: XCTestCase {
         let _ = LocalFeedLoader(store: store)
         XCTAssertEqual(store.deleteCachedFeedCallCount, 0)
     }
+    
+    func test_save_requestsCacheDeletion() {
+        let store = FeedStore()
+        let sut = LocalFeedLoader(store: store)
+        let items = [uniqueItem()]
+        sut.save(items)
+        XCTAssertEqual(store.deleteCachedFeedCallCount, 1)
+    }
+    
+    func uniqueItem() -> FeedItem {
+        return FeedItem(id: UUID(), description: "any", location: "any", imageURL: anyURL())
+    }
+    
+    private func anyURL() -> URL {
+        URL(string: "http://any-url.com")!
+    }
 }

From 6c585fc38b94f3ba81226d9855adf7a859afec48 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:21:59 +0200
Subject: [PATCH 004/159] Extract system under test creation to a factory
 method to protect tests against breaking changes

---
 .../Feed Cache/CacheFeedUseCaseTests.swift         | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 8a8acaf..a7f07f2 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -29,19 +29,25 @@ class FeedStore {
 class CacheFeedUseCaseTests: XCTestCase {
     
     func test_doesNotDeleteCacheUponCreation() {
-        let store = FeedStore()
-        let _ = LocalFeedLoader(store: store)
+        let (_, store) = makeSUT()
         XCTAssertEqual(store.deleteCachedFeedCallCount, 0)
     }
     
     func test_save_requestsCacheDeletion() {
-        let store = FeedStore()
-        let sut = LocalFeedLoader(store: store)
+        let (sut, store) = makeSUT()
         let items = [uniqueItem()]
         sut.save(items)
         XCTAssertEqual(store.deleteCachedFeedCallCount, 1)
     }
     
+    // MARK: - Helpers
+    
+    private func makeSUT() -> (sut: LocalFeedLoader, store: FeedStore) {
+        let store = FeedStore()
+        let sut = LocalFeedLoader(store: store)
+        return (sut, store)
+    }
+    
     func uniqueItem() -> FeedItem {
         return FeedItem(id: UUID(), description: "any", location: "any", imageURL: anyURL())
     }

From a98769c1f76a5eeab50622e54c5b00813b2334fc Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:22:58 +0200
Subject: [PATCH 005/159] Move memory leak tracking extension from the Feed API
 module scope to a module-level shared scope

---
 EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj    | 9 ++++++---
 .../Helpers/XCTestCase+MemoryLeakTrackingHelper.swift    | 0
 2 files changed, 6 insertions(+), 3 deletions(-)
 rename EssentialFeed/EssentialFeedTests/{Feed Api => }/Helpers/XCTestCase+MemoryLeakTrackingHelper.swift (100%)

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index dd3d805..254b83d 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -43,10 +43,10 @@
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
-		40B002502CF9F0420058D3E0 /* PBXFileSystemSynchronizedBuildFileExceptionSet */ = {
+		40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */ = {
 			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
 			membershipExceptions = (
-				"Helpers/XCTestCase+MemoryLeakTrackingHelper.swift",
+				"XCTestCase+MemoryLeakTrackingHelper.swift",
 			);
 			target = 40B002442CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */;
 		};
@@ -63,8 +63,9 @@
 /* End PBXFileSystemSynchronizedBuildFileExceptionSet section */
 
 /* Begin PBXFileSystemSynchronizedRootGroup section */
-		40124C322CF8BDD5008BBDB6 /* Feed Api */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40B002502CF9F0420058D3E0 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = "Feed Api"; sourceTree = "<group>"; };
+		40124C322CF8BDD5008BBDB6 /* Feed Api */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = "Feed Api"; sourceTree = "<group>"; };
 		40B002462CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = EssentialFeedAPIEndToEndTests; sourceTree = "<group>"; };
+		40B9753D2D9E7CB2009652B5 /* Helpers */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = Helpers; sourceTree = "<group>"; };
 		40C57D7A2CF7C16E00518522 /* FeedApi */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40C57D7D2CF7C19100518522 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = FeedApi; sourceTree = "<group>"; };
 /* End PBXFileSystemSynchronizedRootGroup section */
 
@@ -128,6 +129,7 @@
 		080EDEFE21B6DA7E00813479 /* EssentialFeedTests */ = {
 			isa = PBXGroup;
 			children = (
+				40B9753D2D9E7CB2009652B5 /* Helpers */,
 				40B975392D9E7AD3009652B5 /* Feed Cache */,
 				40124C322CF8BDD5008BBDB6 /* Feed Api */,
 				080EDF0121B6DA7E00813479 /* Info.plist */,
@@ -198,6 +200,7 @@
 			);
 			fileSystemSynchronizedGroups = (
 				40124C322CF8BDD5008BBDB6 /* Feed Api */,
+				40B9753D2D9E7CB2009652B5 /* Helpers */,
 			);
 			name = EssentialFeedTests;
 			productName = EssentialFeedTests;
diff --git a/EssentialFeed/EssentialFeedTests/Feed Api/Helpers/XCTestCase+MemoryLeakTrackingHelper.swift b/EssentialFeed/EssentialFeedTests/Helpers/XCTestCase+MemoryLeakTrackingHelper.swift
similarity index 100%
rename from EssentialFeed/EssentialFeedTests/Feed Api/Helpers/XCTestCase+MemoryLeakTrackingHelper.swift
rename to EssentialFeed/EssentialFeedTests/Helpers/XCTestCase+MemoryLeakTrackingHelper.swift

From 841817ff66437b316aa12b7385a7d9bf13999cf8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:23:55 +0200
Subject: [PATCH 006/159] Add memory leak tracking

---
 .../EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index a7f07f2..2822444 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -42,9 +42,11 @@ class CacheFeedUseCaseTests: XCTestCase {
     
     // MARK: - Helpers
     
-    private func makeSUT() -> (sut: LocalFeedLoader, store: FeedStore) {
+    private func makeSUT(file: StaticString = #file, line: UInt = #line) -> (sut: LocalFeedLoader, store: FeedStore) {
         let store = FeedStore()
         let sut = LocalFeedLoader(store: store)
+        trackForMemoryLeaks(store, file: file, line: line)
+        trackForMemoryLeaks(sut, file: file, line: line)
         return (sut, store)
     }
     

From 1848e88f6cb28c1cb0dc235cf10f44c5f5df36bb Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:26:33 +0200
Subject: [PATCH 007/159] Save command does not request cache insertion on
 deletion error

---
 .../Feed Cache/CacheFeedUseCaseTests.swift      | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 2822444..4e57875 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -18,12 +18,18 @@ class LocalFeedLoader {
         store.deleteCachedFeed()
     }
 }
+
 class FeedStore {
     var deleteCachedFeedCallCount = 0
+    var insertCallCount = 0
     
     func deleteCachedFeed() {
         deleteCachedFeedCallCount += 1
     }
+    
+    func completeDeletion(with error: Error, at index: Int = 0) {
+        
+    }
 }
 
 class CacheFeedUseCaseTests: XCTestCase {
@@ -40,6 +46,15 @@ class CacheFeedUseCaseTests: XCTestCase {
         XCTAssertEqual(store.deleteCachedFeedCallCount, 1)
     }
     
+    func test_save_doesNotRequestCacheInsertionOnDeletionError() {
+        let (sut, store) = makeSUT()
+        let items = [uniqueItem()]
+        let deletionError = anyNSError()
+        sut.save(items)
+        store.completeDeletion(with: deletionError)
+        XCTAssertEqual(store.insertCallCount, 0)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(file: StaticString = #file, line: UInt = #line) -> (sut: LocalFeedLoader, store: FeedStore) {
@@ -57,4 +72,6 @@ class CacheFeedUseCaseTests: XCTestCase {
     private func anyURL() -> URL {
         URL(string: "http://any-url.com")!
     }
+    
+    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
 }

From a31734318c9ce0da6437fda68b7197b6eee7f1f3 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:31:58 +0200
Subject: [PATCH 008/159] Save command requests new cache insertion on
 succesful deletion

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 30 +++++++++++++++++--
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 4e57875..9942783 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -15,7 +15,11 @@ class LocalFeedLoader {
     }
     
     func save(_ items: [FeedItem]) {
-        store.deleteCachedFeed()
+        store.deleteCachedFeed { [unowned self] error in
+            if error == nil {
+                self.store.insert(items)
+            }
+        }
     }
 }
 
@@ -23,12 +27,24 @@ class FeedStore {
     var deleteCachedFeedCallCount = 0
     var insertCallCount = 0
     
-    func deleteCachedFeed() {
+    typealias DeletionCompletion = (Error?) -> Void
+    private var deletionCompletions = [DeletionCompletion]()
+    
+    func deleteCachedFeed(completion: @escaping DeletionCompletion) {
         deleteCachedFeedCallCount += 1
+        deletionCompletions.append(completion)
     }
     
     func completeDeletion(with error: Error, at index: Int = 0) {
-        
+        deletionCompletions[index](error)
+    }
+    
+    func completeDeletionSuccesfully(at index: Int = 0) {
+        deletionCompletions[index](nil)
+    }
+    
+    func insert(_ items: [FeedItem]) {
+        insertCallCount += 1
     }
 }
 
@@ -55,6 +71,14 @@ class CacheFeedUseCaseTests: XCTestCase {
         XCTAssertEqual(store.insertCallCount, 0)
     }
     
+    func test_save_requestsNewCacheInsertionOnSuccesfulDeletion() {
+        let (sut, store) = makeSUT()
+        let items = [uniqueItem()]
+        sut.save(items)
+        store.completeDeletionSuccesfully()
+        XCTAssertEqual(store.insertCallCount, 1)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(file: StaticString = #file, line: UInt = #line) -> (sut: LocalFeedLoader, store: FeedStore) {

From b9b79db3ec7350eb333241319ece52e597e4c7d4 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:38:42 +0200
Subject: [PATCH 009/159] Save command requests cache insertion with timestamp
 on succesful deletion

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 34 +++++++++++++++----
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 9942783..acb35e6 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -10,24 +10,27 @@ import XCTest
 
 class LocalFeedLoader {
     private let store: FeedStore
-    init(store: FeedStore) {
+    private let currentDate: () -> Date
+    init(store: FeedStore, currentDate: @escaping () -> Date) {
         self.store = store
+        self.currentDate = currentDate
     }
     
     func save(_ items: [FeedItem]) {
         store.deleteCachedFeed { [unowned self] error in
             if error == nil {
-                self.store.insert(items)
+                self.store.insert(items, timestamp: self.currentDate())
             }
         }
     }
 }
 
 class FeedStore {
+    typealias DeletionCompletion = (Error?) -> Void
+    
     var deleteCachedFeedCallCount = 0
     var insertCallCount = 0
-    
-    typealias DeletionCompletion = (Error?) -> Void
+    var insertions = [(items: [FeedItem], timestamp: Date)]()
     private var deletionCompletions = [DeletionCompletion]()
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion) {
@@ -43,8 +46,9 @@ class FeedStore {
         deletionCompletions[index](nil)
     }
     
-    func insert(_ items: [FeedItem]) {
+    func insert(_ items: [FeedItem], timestamp: Date) {
         insertCallCount += 1
+        insertions.append((items, timestamp))
     }
 }
 
@@ -79,11 +83,27 @@ class CacheFeedUseCaseTests: XCTestCase {
         XCTAssertEqual(store.insertCallCount, 1)
     }
     
+    func test_save_requestsNewCacheInsertionWithTimestampOnSuccesfulDeletion() {
+        let timestamp = Date()
+        let (sut, store) = makeSUT(currentDate: { timestamp })
+        let items = [uniqueItem()]
+        sut.save(items)
+        store.completeDeletionSuccesfully()
+        
+        XCTAssertEqual(store.insertions.count, 1)
+        XCTAssertEqual(store.insertions.first?.items, items)
+        XCTAssertEqual(store.insertions.first?.timestamp, timestamp)
+    }
+    
     // MARK: - Helpers
     
-    private func makeSUT(file: StaticString = #file, line: UInt = #line) -> (sut: LocalFeedLoader, store: FeedStore) {
+    private func makeSUT(
+        currentDate: @escaping () -> Date = Date.init,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) -> (sut: LocalFeedLoader, store: FeedStore) {
         let store = FeedStore()
-        let sut = LocalFeedLoader(store: store)
+        let sut = LocalFeedLoader(store: store, currentDate: currentDate)
         trackForMemoryLeaks(store, file: file, line: line)
         trackForMemoryLeaks(sut, file: file, line: line)
         return (sut, store)

From dc8b1aa63abee8a07408114305f61d39422fb482 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:39:26 +0200
Subject: [PATCH 010/159] Remove redundant test code

---
 .../Feed Cache/CacheFeedUseCaseTests.swift           | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index acb35e6..20d0825 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -29,7 +29,6 @@ class FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     
     var deleteCachedFeedCallCount = 0
-    var insertCallCount = 0
     var insertions = [(items: [FeedItem], timestamp: Date)]()
     private var deletionCompletions = [DeletionCompletion]()
     
@@ -47,7 +46,6 @@ class FeedStore {
     }
     
     func insert(_ items: [FeedItem], timestamp: Date) {
-        insertCallCount += 1
         insertions.append((items, timestamp))
     }
 }
@@ -72,15 +70,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let deletionError = anyNSError()
         sut.save(items)
         store.completeDeletion(with: deletionError)
-        XCTAssertEqual(store.insertCallCount, 0)
-    }
-    
-    func test_save_requestsNewCacheInsertionOnSuccesfulDeletion() {
-        let (sut, store) = makeSUT()
-        let items = [uniqueItem()]
-        sut.save(items)
-        store.completeDeletionSuccesfully()
-        XCTAssertEqual(store.insertCallCount, 1)
+        XCTAssertEqual(store.insertions.count, 0)
     }
     
     func test_save_requestsNewCacheInsertionWithTimestampOnSuccesfulDeletion() {

From e3ab1aeced0129b34b9d3564b4a79b55e91a3021 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 10:45:21 +0200
Subject: [PATCH 011/159] Unify store helper received messages to guarantee
 order and simplify tests assertions

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 24 ++++++++++---------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 20d0825..18e0a15 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -28,13 +28,17 @@ class LocalFeedLoader {
 class FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     
-    var deleteCachedFeedCallCount = 0
-    var insertions = [(items: [FeedItem], timestamp: Date)]()
     private var deletionCompletions = [DeletionCompletion]()
+    private(set) var receivedMessages = [ReceivedMessage]()
+    
+    enum ReceivedMessage: Equatable {
+        case deleteCachedFeed
+        case insert([FeedItem], Date)
+    }
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        deleteCachedFeedCallCount += 1
         deletionCompletions.append(completion)
+        receivedMessages.append(.deleteCachedFeed)
     }
     
     func completeDeletion(with error: Error, at index: Int = 0) {
@@ -46,22 +50,22 @@ class FeedStore {
     }
     
     func insert(_ items: [FeedItem], timestamp: Date) {
-        insertions.append((items, timestamp))
+        receivedMessages.append(.insert(items, timestamp))
     }
 }
 
 class CacheFeedUseCaseTests: XCTestCase {
     
-    func test_doesNotDeleteCacheUponCreation() {
+    func test_doesNotMessageStoreUponCreation() {
         let (_, store) = makeSUT()
-        XCTAssertEqual(store.deleteCachedFeedCallCount, 0)
+        XCTAssertEqual(store.receivedMessages, [])
     }
     
     func test_save_requestsCacheDeletion() {
         let (sut, store) = makeSUT()
         let items = [uniqueItem()]
         sut.save(items)
-        XCTAssertEqual(store.deleteCachedFeedCallCount, 1)
+        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
     
     func test_save_doesNotRequestCacheInsertionOnDeletionError() {
@@ -70,7 +74,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let deletionError = anyNSError()
         sut.save(items)
         store.completeDeletion(with: deletionError)
-        XCTAssertEqual(store.insertions.count, 0)
+        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
     
     func test_save_requestsNewCacheInsertionWithTimestampOnSuccesfulDeletion() {
@@ -80,9 +84,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         sut.save(items)
         store.completeDeletionSuccesfully()
         
-        XCTAssertEqual(store.insertions.count, 1)
-        XCTAssertEqual(store.insertions.first?.items, items)
-        XCTAssertEqual(store.insertions.first?.timestamp, timestamp)
+        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(items, timestamp)])
     }
     
     // MARK: - Helpers

From d985e6bd75da3079cd3962b1d8850841f961803c Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 11:29:44 +0200
Subject: [PATCH 012/159] Save commands fails on cache deletion error

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 24 +++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 18e0a15..0f4500d 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -16,8 +16,9 @@ class LocalFeedLoader {
         self.currentDate = currentDate
     }
     
-    func save(_ items: [FeedItem]) {
+    func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
         store.deleteCachedFeed { [unowned self] error in
+            completion(error)
             if error == nil {
                 self.store.insert(items, timestamp: self.currentDate())
             }
@@ -64,7 +65,7 @@ class CacheFeedUseCaseTests: XCTestCase {
     func test_save_requestsCacheDeletion() {
         let (sut, store) = makeSUT()
         let items = [uniqueItem()]
-        sut.save(items)
+        sut.save(items) { _ in }
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
     
@@ -72,7 +73,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let (sut, store) = makeSUT()
         let items = [uniqueItem()]
         let deletionError = anyNSError()
-        sut.save(items)
+        sut.save(items) { _ in }
         store.completeDeletion(with: deletionError)
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
@@ -81,12 +82,27 @@ class CacheFeedUseCaseTests: XCTestCase {
         let timestamp = Date()
         let (sut, store) = makeSUT(currentDate: { timestamp })
         let items = [uniqueItem()]
-        sut.save(items)
+        sut.save(items) { _ in }
         store.completeDeletionSuccesfully()
         
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(items, timestamp)])
     }
     
+    func test_save_failsOnDeletionError() {
+        let items = [uniqueItem()]
+        let (sut, store) = makeSUT()
+        let deletionError = anyNSError()
+        let exp = expectation(description: "Wait for save completion")
+        var receivedError: Error?
+        sut.save(items) { error in
+            receivedError = error
+            exp.fulfill()
+        }
+        store.completeDeletion(with: deletionError)
+        wait(for: [exp], timeout: 1.0)
+        XCTAssertEqual(receivedError as NSError?, deletionError)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From bc909e6063a499d98ec9d4407cbb3012540b0ff6 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 11:38:52 +0200
Subject: [PATCH 013/159] Save command fails on cache insertion error

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 30 +++++++++++++++++--
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 0f4500d..95b73e0 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -18,9 +18,10 @@ class LocalFeedLoader {
     
     func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
         store.deleteCachedFeed { [unowned self] error in
-            completion(error)
             if error == nil {
-                self.store.insert(items, timestamp: self.currentDate())
+                self.store.insert(items, timestamp: self.currentDate(), completion: completion)
+            } else {
+                completion(error)
             }
         }
     }
@@ -28,8 +29,10 @@ class LocalFeedLoader {
 
 class FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
+    typealias InsertionCompletion = (Error?) -> Void
     
     private var deletionCompletions = [DeletionCompletion]()
+    private var insertionCompletions = [InsertionCompletion]()
     private(set) var receivedMessages = [ReceivedMessage]()
     
     enum ReceivedMessage: Equatable {
@@ -50,9 +53,14 @@ class FeedStore {
         deletionCompletions[index](nil)
     }
     
-    func insert(_ items: [FeedItem], timestamp: Date) {
+    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion) {
+        insertionCompletions.append(completion)
         receivedMessages.append(.insert(items, timestamp))
     }
+    
+    func completeInsertion(with error: Error, at index: Int = 0) {
+        insertionCompletions[index](error)
+    }
 }
 
 class CacheFeedUseCaseTests: XCTestCase {
@@ -103,6 +111,22 @@ class CacheFeedUseCaseTests: XCTestCase {
         XCTAssertEqual(receivedError as NSError?, deletionError)
     }
     
+    func test_save_failsOnInsertionError() {
+        let items = [uniqueItem()]
+        let (sut, store) = makeSUT()
+        let insertionError = anyNSError()
+        let exp = expectation(description: "Wait for save completion")
+        var receivedError: Error?
+        sut.save(items) { error in
+            receivedError = error
+            exp.fulfill()
+        }
+        store.completeDeletionSuccesfully()
+        store.completeInsertion(with: insertionError)
+        wait(for: [exp], timeout: 1.0)
+        XCTAssertEqual(receivedError as NSError?, insertionError)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 0c8d98795fafdb179c816a72c4cdb7c4a46600ff Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 11:41:41 +0200
Subject: [PATCH 014/159] Save command succeds on succesful cache insertion

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 95b73e0..66b1837 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -61,6 +61,10 @@ class FeedStore {
     func completeInsertion(with error: Error, at index: Int = 0) {
         insertionCompletions[index](error)
     }
+    
+    func completeInsertionSuccesfully(at index: Int = 0) {
+        insertionCompletions[index](nil)
+    }
 }
 
 class CacheFeedUseCaseTests: XCTestCase {
@@ -127,6 +131,21 @@ class CacheFeedUseCaseTests: XCTestCase {
         XCTAssertEqual(receivedError as NSError?, insertionError)
     }
     
+    func test_save_succeedsOnSuccesfulCacheInsertion() {
+        let items = [uniqueItem()]
+        let (sut, store) = makeSUT()
+        let exp = expectation(description: "Wait for save completion")
+        var receivedError: Error?
+        sut.save(items) { error in
+            receivedError = error
+            exp.fulfill()
+        }
+        store.completeDeletionSuccesfully()
+        store.completeInsertionSuccesfully()
+        wait(for: [exp], timeout: 1.0)
+        XCTAssertNil(receivedError as NSError?)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 0a6a7834266f9d0b4175e7e5f9af29cfc6634718 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 11:48:24 +0200
Subject: [PATCH 015/159] Extract duplicated test code into a shared helper
 method

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 69 ++++++++++---------
 1 file changed, 37 insertions(+), 32 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 66b1837..8fcc524 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -101,49 +101,29 @@ class CacheFeedUseCaseTests: XCTestCase {
     }
     
     func test_save_failsOnDeletionError() {
-        let items = [uniqueItem()]
         let (sut, store) = makeSUT()
         let deletionError = anyNSError()
-        let exp = expectation(description: "Wait for save completion")
-        var receivedError: Error?
-        sut.save(items) { error in
-            receivedError = error
-            exp.fulfill()
-        }
-        store.completeDeletion(with: deletionError)
-        wait(for: [exp], timeout: 1.0)
-        XCTAssertEqual(receivedError as NSError?, deletionError)
+        expect(sut, toCompleteWithError: deletionError, when: {
+            store.completeDeletion(with: deletionError)
+        })
     }
     
     func test_save_failsOnInsertionError() {
-        let items = [uniqueItem()]
+      
         let (sut, store) = makeSUT()
         let insertionError = anyNSError()
-        let exp = expectation(description: "Wait for save completion")
-        var receivedError: Error?
-        sut.save(items) { error in
-            receivedError = error
-            exp.fulfill()
-        }
-        store.completeDeletionSuccesfully()
-        store.completeInsertion(with: insertionError)
-        wait(for: [exp], timeout: 1.0)
-        XCTAssertEqual(receivedError as NSError?, insertionError)
+        expect(sut, toCompleteWithError: insertionError, when: {
+            store.completeDeletionSuccesfully()
+            store.completeInsertion(with: insertionError)
+        })
     }
     
     func test_save_succeedsOnSuccesfulCacheInsertion() {
-        let items = [uniqueItem()]
         let (sut, store) = makeSUT()
-        let exp = expectation(description: "Wait for save completion")
-        var receivedError: Error?
-        sut.save(items) { error in
-            receivedError = error
-            exp.fulfill()
-        }
-        store.completeDeletionSuccesfully()
-        store.completeInsertionSuccesfully()
-        wait(for: [exp], timeout: 1.0)
-        XCTAssertNil(receivedError as NSError?)
+        expect(sut, toCompleteWithError: nil, when: {
+            store.completeDeletionSuccesfully()
+            store.completeInsertionSuccesfully()
+        })
     }
     
     // MARK: - Helpers
@@ -160,6 +140,31 @@ class CacheFeedUseCaseTests: XCTestCase {
         return (sut, store)
     }
     
+    private func expect(
+        _ sut: LocalFeedLoader,
+        toCompleteWithError expectedError: NSError?,
+        when action: () -> Void,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let exp = expectation(description: "Wait for save completion")
+        var receivedError: Error?
+        sut.save([uniqueItem()]) { error in
+            receivedError = error
+            exp.fulfill()
+        }
+        
+        action()
+        
+        wait(for: [exp], timeout: 1.0)
+        XCTAssertEqual(
+            receivedError as NSError?,
+            expectedError,
+            file: file,
+            line: line
+        )
+    }
+    
     func uniqueItem() -> FeedItem {
         return FeedItem(id: UUID(), description: "any", location: "any", imageURL: anyURL())
     }

From 7a638318a4b24be29b4ba4af3292d0d6a4f290e8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 11:52:09 +0200
Subject: [PATCH 016/159] Extract FeedStore protocol into a FeedStoreSpy helper

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 79 ++++++++++---------
 1 file changed, 42 insertions(+), 37 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 8fcc524..e5e6eb6 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -27,44 +27,12 @@ class LocalFeedLoader {
     }
 }
 
-class FeedStore {
+protocol FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     typealias InsertionCompletion = (Error?) -> Void
     
-    private var deletionCompletions = [DeletionCompletion]()
-    private var insertionCompletions = [InsertionCompletion]()
-    private(set) var receivedMessages = [ReceivedMessage]()
-    
-    enum ReceivedMessage: Equatable {
-        case deleteCachedFeed
-        case insert([FeedItem], Date)
-    }
-    
-    func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        deletionCompletions.append(completion)
-        receivedMessages.append(.deleteCachedFeed)
-    }
-    
-    func completeDeletion(with error: Error, at index: Int = 0) {
-        deletionCompletions[index](error)
-    }
-    
-    func completeDeletionSuccesfully(at index: Int = 0) {
-        deletionCompletions[index](nil)
-    }
-    
-    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion) {
-        insertionCompletions.append(completion)
-        receivedMessages.append(.insert(items, timestamp))
-    }
-    
-    func completeInsertion(with error: Error, at index: Int = 0) {
-        insertionCompletions[index](error)
-    }
-    
-    func completeInsertionSuccesfully(at index: Int = 0) {
-        insertionCompletions[index](nil)
-    }
+    func deleteCachedFeed(completion: @escaping DeletionCompletion)
+    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
 }
 
 class CacheFeedUseCaseTests: XCTestCase {
@@ -132,8 +100,8 @@ class CacheFeedUseCaseTests: XCTestCase {
         currentDate: @escaping () -> Date = Date.init,
         file: StaticString = #file,
         line: UInt = #line
-    ) -> (sut: LocalFeedLoader, store: FeedStore) {
-        let store = FeedStore()
+    ) -> (sut: LocalFeedLoader, store: FeedStoreSpy) {
+        let store = FeedStoreSpy()
         let sut = LocalFeedLoader(store: store, currentDate: currentDate)
         trackForMemoryLeaks(store, file: file, line: line)
         trackForMemoryLeaks(sut, file: file, line: line)
@@ -174,4 +142,41 @@ class CacheFeedUseCaseTests: XCTestCase {
     }
     
     private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
+    
+    private class FeedStoreSpy: FeedStore {
+        private var deletionCompletions = [DeletionCompletion]()
+        private var insertionCompletions = [InsertionCompletion]()
+        private(set) var receivedMessages = [ReceivedMessage]()
+        
+        enum ReceivedMessage: Equatable {
+            case deleteCachedFeed
+            case insert([FeedItem], Date)
+        }
+        
+        func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+            deletionCompletions.append(completion)
+            receivedMessages.append(.deleteCachedFeed)
+        }
+        
+        func completeDeletion(with error: Error, at index: Int = 0) {
+            deletionCompletions[index](error)
+        }
+        
+        func completeDeletionSuccesfully(at index: Int = 0) {
+            deletionCompletions[index](nil)
+        }
+        
+        func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion) {
+            insertionCompletions.append(completion)
+            receivedMessages.append(.insert(items, timestamp))
+        }
+        
+        func completeInsertion(with error: Error, at index: Int = 0) {
+            insertionCompletions[index](error)
+        }
+        
+        func completeInsertionSuccesfully(at index: Int = 0) {
+            insertionCompletions[index](nil)
+        }
+    }
 }

From 527ac0332807500c6841840fbd6212cd7f5f55a0 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:45:55 +0200
Subject: [PATCH 017/159] Guarantee that the `LocalFeedLoader`does not delvier
 deletion error after instance has been deallocated

---
 .../Feed Cache/CacheFeedUseCaseTests.swift          | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index e5e6eb6..93708a0 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -17,7 +17,8 @@ class LocalFeedLoader {
     }
     
     func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
-        store.deleteCachedFeed { [unowned self] error in
+        store.deleteCachedFeed { [weak self] error in
+            guard let self else { return }
             if error == nil {
                 self.store.insert(items, timestamp: self.currentDate(), completion: completion)
             } else {
@@ -94,6 +95,16 @@ class CacheFeedUseCaseTests: XCTestCase {
         })
     }
     
+    func test_save_doesNotDeliverDeletionErrorAfterSUTInstanceHasBeenDeallocated() {
+        let store = FeedStoreSpy()
+        var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
+        var receivedResults = [Error?]()
+        sut?.save([uniqueItem()]) { receivedResults.append($0) }
+        sut = nil
+        store.completeDeletion(with: anyNSError())
+        XCTAssertTrue(receivedResults.isEmpty)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From dd954dee6f7ddf5716d8373c060f75ce0166d20b Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:48:20 +0200
Subject: [PATCH 018/159] Guarantee that the `LocalFeedLoader`does not deliver
 insertion error after instance has been deallocated

---
 .../Feed Cache/CacheFeedUseCaseTests.swift      | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 93708a0..e0ff378 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -20,7 +20,11 @@ class LocalFeedLoader {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }
             if error == nil {
-                self.store.insert(items, timestamp: self.currentDate(), completion: completion)
+                self.store.insert(items, timestamp: self.currentDate())  { [weak self] error in
+                    guard self != nil else { return }
+                    completion(error)
+                    
+                }
             } else {
                 completion(error)
             }
@@ -105,6 +109,17 @@ class CacheFeedUseCaseTests: XCTestCase {
         XCTAssertTrue(receivedResults.isEmpty)
     }
     
+    func test_save_doesNotDeliverInsertionErrorAfterSUTInstanceHasBeenDeallocated() {
+        let store = FeedStoreSpy()
+        var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
+        var receivedResults = [Error?]()
+        sut?.save([uniqueItem()]) { receivedResults.append($0) }
+        store.completeDeletionSuccesfully()
+        sut = nil
+        store.completeInsertion(with: anyNSError())
+        XCTAssertTrue(receivedResults.isEmpty)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From bec426a9fab8442defba6cbe9e08d3c24315a3f9 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:49:49 +0200
Subject: [PATCH 019/159] Invert `if` logic to make code paths easier to follow

---
 .../Feed Cache/CacheFeedUseCaseTests.swift                | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index e0ff378..11c8291 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -19,14 +19,14 @@ class LocalFeedLoader {
     func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }
-            if error == nil {
+            if let cacheDeletionError = error {
+                completion(cacheDeletionError)
+            } else {
                 self.store.insert(items, timestamp: self.currentDate())  { [weak self] error in
                     guard self != nil else { return }
                     completion(error)
                     
                 }
-            } else {
-                completion(error)
             }
         }
     }
@@ -82,7 +82,7 @@ class CacheFeedUseCaseTests: XCTestCase {
     }
     
     func test_save_failsOnInsertionError() {
-      
+        
         let (sut, store) = makeSUT()
         let insertionError = anyNSError()
         expect(sut, toCompleteWithError: insertionError, when: {

From 7c197d303cc98e5568cb165f1c00de45424a71c7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:51:13 +0200
Subject: [PATCH 020/159] Extract cache insertion into a helper function to
 make logic inside closure callbacks easier to follow

---
 .../Feed Cache/CacheFeedUseCaseTests.swift          | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 11c8291..d5aeddf 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -22,14 +22,17 @@ class LocalFeedLoader {
             if let cacheDeletionError = error {
                 completion(cacheDeletionError)
             } else {
-                self.store.insert(items, timestamp: self.currentDate())  { [weak self] error in
-                    guard self != nil else { return }
-                    completion(error)
-                    
-                }
+                self.cache(items, with: completion)
             }
         }
     }
+    
+    private func cache(_ items: [FeedItem], with completion: @escaping (Error?) -> Void) {
+        store.insert(items, timestamp: currentDate())  { [weak self] error in
+            guard self != nil else { return }
+            completion(error)
+        }
+    }
 }
 
 protocol FeedStore {

From 0d5609583ad3c91cc44213b4dc9d617f7b3ddc62 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:53:07 +0200
Subject: [PATCH 021/159] Move `LocalFeedLoader` and `FeedStore` collaborator
 to its own file in production

---
 .../EssentialFeed.xcodeproj/project.pbxproj   | 12 ++++++
 .../Feed Cache/LocalFeedLoader.swift          | 42 +++++++++++++++++++
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 34 ---------------
 3 files changed, 54 insertions(+), 34 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 254b83d..d809a82 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -12,6 +12,7 @@
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
+		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -40,6 +41,7 @@
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
+		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -119,6 +121,7 @@
 		080EDEF321B6DA7E00813479 /* EssentialFeed */ = {
 			isa = PBXGroup;
 			children = (
+				40B975412D9E9FB7009652B5 /* Feed Cache */,
 				40C57D7A2CF7C16E00518522 /* FeedApi */,
 				080EDEF521B6DA7E00813479 /* Info.plist */,
 				080EDF1021B6DFA200813479 /* Feed Feature */,
@@ -154,6 +157,14 @@
 			path = "Feed Cache";
 			sourceTree = "<group>";
 		};
+		40B975412D9E9FB7009652B5 /* Feed Cache */ = {
+			isa = PBXGroup;
+			children = (
+				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
+			);
+			path = "Feed Cache";
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXHeadersBuildPhase section */
@@ -305,6 +316,7 @@
 			files = (
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
 				080EDF0C21B6DAE800813479 /* FeedItem.swift in Sources */,
+				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
new file mode 100644
index 0000000..50c6e7d
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -0,0 +1,42 @@
+//
+//  LocalFeedLoader.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+import Foundation
+
+public final class LocalFeedLoader {
+    private let store: FeedStore
+    private let currentDate: () -> Date
+    public init(store: FeedStore, currentDate: @escaping () -> Date) {
+        self.store = store
+        self.currentDate = currentDate
+    }
+    
+    public func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
+        store.deleteCachedFeed { [weak self] error in
+            guard let self else { return }
+            if let cacheDeletionError = error {
+                completion(cacheDeletionError)
+            } else {
+                self.cache(items, with: completion)
+            }
+        }
+    }
+    
+    private func cache(_ items: [FeedItem], with completion: @escaping (Error?) -> Void) {
+        store.insert(items, timestamp: currentDate())  { [weak self] error in
+            guard self != nil else { return }
+            completion(error)
+        }
+    }
+}
+
+public protocol FeedStore {
+    typealias DeletionCompletion = (Error?) -> Void
+    typealias InsertionCompletion = (Error?) -> Void
+    
+    func deleteCachedFeed(completion: @escaping DeletionCompletion)
+    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index d5aeddf..6fce264 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -8,40 +8,6 @@
 import EssentialFeed
 import XCTest
 
-class LocalFeedLoader {
-    private let store: FeedStore
-    private let currentDate: () -> Date
-    init(store: FeedStore, currentDate: @escaping () -> Date) {
-        self.store = store
-        self.currentDate = currentDate
-    }
-    
-    func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
-        store.deleteCachedFeed { [weak self] error in
-            guard let self else { return }
-            if let cacheDeletionError = error {
-                completion(cacheDeletionError)
-            } else {
-                self.cache(items, with: completion)
-            }
-        }
-    }
-    
-    private func cache(_ items: [FeedItem], with completion: @escaping (Error?) -> Void) {
-        store.insert(items, timestamp: currentDate())  { [weak self] error in
-            guard self != nil else { return }
-            completion(error)
-        }
-    }
-}
-
-protocol FeedStore {
-    typealias DeletionCompletion = (Error?) -> Void
-    typealias InsertionCompletion = (Error?) -> Void
-    
-    func deleteCachedFeed(completion: @escaping DeletionCompletion)
-    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
-}
 
 class CacheFeedUseCaseTests: XCTestCase {
     

From e015d61ff24e3fe51f751d33a6ce8a9a9889cf67 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:53:33 +0200
Subject: [PATCH 022/159] Move `FeedStore` to its own file

---
 .../EssentialFeed.xcodeproj/project.pbxproj     |  4 ++++
 .../EssentialFeed/Feed Cache/FeedStore.swift    | 17 +++++++++++++++++
 .../Feed Cache/LocalFeedLoader.swift            |  8 +-------
 3 files changed, 22 insertions(+), 7 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index d809a82..a314055 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -13,6 +13,7 @@
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
+		40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975442D9EA01D009652B5 /* FeedStore.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -42,6 +43,7 @@
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
+		40B975442D9EA01D009652B5 /* FeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStore.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -161,6 +163,7 @@
 			isa = PBXGroup;
 			children = (
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
+				40B975442D9EA01D009652B5 /* FeedStore.swift */,
 			);
 			path = "Feed Cache";
 			sourceTree = "<group>";
@@ -316,6 +319,7 @@
 			files = (
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
 				080EDF0C21B6DAE800813479 /* FeedItem.swift in Sources */,
+				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
new file mode 100644
index 0000000..f1c1e29
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -0,0 +1,17 @@
+//
+//  FeedStore.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+
+
+import Foundation
+
+public protocol FeedStore {
+    typealias DeletionCompletion = (Error?) -> Void
+    typealias InsertionCompletion = (Error?) -> Void
+    
+    func deleteCachedFeed(completion: @escaping DeletionCompletion)
+    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
+}
\ No newline at end of file
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 50c6e7d..f7a264b 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -33,10 +33,4 @@ public final class LocalFeedLoader {
     }
 }
 
-public protocol FeedStore {
-    typealias DeletionCompletion = (Error?) -> Void
-    typealias InsertionCompletion = (Error?) -> Void
-    
-    func deleteCachedFeed(completion: @escaping DeletionCompletion)
-    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
-}
+

From af967ce0d1588ae11fc29b6b7a10e752a6c5e4ba Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 12:55:27 +0200
Subject: [PATCH 023/159] Add `SaveResult` typealias to protect code from
 potential breaking changes

---
 EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift    | 3 +--
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift        | 8 ++++----
 .../Feed Cache/CacheFeedUseCaseTests.swift                | 4 ++--
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index f1c1e29..b4be4eb 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -5,7 +5,6 @@
 //  Created by Cristian Felipe Patiño Rojas on 3/4/25.
 //
 
-
 import Foundation
 
 public protocol FeedStore {
@@ -14,4 +13,4 @@ public protocol FeedStore {
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
     func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
-}
\ No newline at end of file
+}
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index f7a264b..4117bf2 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -9,12 +9,14 @@ import Foundation
 public final class LocalFeedLoader {
     private let store: FeedStore
     private let currentDate: () -> Date
+    
+    public typealias SaveResult = Error?
     public init(store: FeedStore, currentDate: @escaping () -> Date) {
         self.store = store
         self.currentDate = currentDate
     }
     
-    public func save(_ items: [FeedItem], completion: @escaping (Error?) -> Void) {
+    public func save(_ items: [FeedItem], completion: @escaping (SaveResult) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }
             if let cacheDeletionError = error {
@@ -25,12 +27,10 @@ public final class LocalFeedLoader {
         }
     }
     
-    private func cache(_ items: [FeedItem], with completion: @escaping (Error?) -> Void) {
+    private func cache(_ items: [FeedItem], with completion: @escaping (SaveResult) -> Void) {
         store.insert(items, timestamp: currentDate())  { [weak self] error in
             guard self != nil else { return }
             completion(error)
         }
     }
 }
-
-
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 6fce264..6b6a8c6 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -71,7 +71,7 @@ class CacheFeedUseCaseTests: XCTestCase {
     func test_save_doesNotDeliverDeletionErrorAfterSUTInstanceHasBeenDeallocated() {
         let store = FeedStoreSpy()
         var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
-        var receivedResults = [Error?]()
+        var receivedResults = [LocalFeedLoader.SaveResult]()
         sut?.save([uniqueItem()]) { receivedResults.append($0) }
         sut = nil
         store.completeDeletion(with: anyNSError())
@@ -81,7 +81,7 @@ class CacheFeedUseCaseTests: XCTestCase {
     func test_save_doesNotDeliverInsertionErrorAfterSUTInstanceHasBeenDeallocated() {
         let store = FeedStoreSpy()
         var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
-        var receivedResults = [Error?]()
+        var receivedResults = [LocalFeedLoader.SaveResult]()
         sut?.save([uniqueItem()]) { receivedResults.append($0) }
         store.completeDeletionSuccesfully()
         sut = nil

From 936c6133c379ddf3542321f6ec564ce9753ee177 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 13:07:46 +0200
Subject: [PATCH 024/159] Add `LocalFeedItem` data transfer representation to
 decouple storage frameworks from `FeedItem`data models

---
 .../EssentialFeed/Feed Cache/FeedStore.swift  | 21 ++++++++++++++++++-
 .../Feed Cache/LocalFeedLoader.swift          | 15 ++++++++++++-
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 14 ++++++++++---
 3 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index b4be4eb..ac7a78a 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -12,5 +12,24 @@ public protocol FeedStore {
     typealias InsertionCompletion = (Error?) -> Void
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
-    func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
+    func insert(_ items: [LocalFeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
+}
+
+public struct LocalFeedItem: Equatable {
+    
+    public let id: UUID
+    public let description: String?
+    public let location: String?
+    public let imageURL: URL
+    
+    public init(
+        id: UUID,
+        description: String?,
+        location: String?,
+        imageURL: URL) {
+        self.id = id
+        self.description = description
+        self.location = location
+        self.imageURL = imageURL
+    }
 }
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 4117bf2..34b0119 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -28,9 +28,22 @@ public final class LocalFeedLoader {
     }
     
     private func cache(_ items: [FeedItem], with completion: @escaping (SaveResult) -> Void) {
-        store.insert(items, timestamp: currentDate())  { [weak self] error in
+        store.insert(items.toLocal(), timestamp: currentDate())  { [weak self] error in
             guard self != nil else { return }
             completion(error)
         }
     }
 }
+
+private extension Array where Element == FeedItem {
+    func toLocal() -> [LocalFeedItem] {
+        return map {
+            LocalFeedItem(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                imageURL: $0.imageURL
+            )
+        }
+    }
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 6b6a8c6..b36ff00 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -36,10 +36,18 @@ class CacheFeedUseCaseTests: XCTestCase {
         let timestamp = Date()
         let (sut, store) = makeSUT(currentDate: { timestamp })
         let items = [uniqueItem()]
+        let localItems = items.map {
+            LocalFeedItem(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                imageURL: $0.imageURL
+            )
+        }
         sut.save(items) { _ in }
         store.completeDeletionSuccesfully()
         
-        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(items, timestamp)])
+        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(localItems, timestamp)])
     }
     
     func test_save_failsOnDeletionError() {
@@ -145,7 +153,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         
         enum ReceivedMessage: Equatable {
             case deleteCachedFeed
-            case insert([FeedItem], Date)
+            case insert([LocalFeedItem], Date)
         }
         
         func deleteCachedFeed(completion: @escaping DeletionCompletion) {
@@ -161,7 +169,7 @@ class CacheFeedUseCaseTests: XCTestCase {
             deletionCompletions[index](nil)
         }
         
-        func insert(_ items: [FeedItem], timestamp: Date, completion: @escaping InsertionCompletion) {
+        func insert(_ items: [LocalFeedItem], timestamp: Date, completion: @escaping InsertionCompletion) {
             insertionCompletions.append(completion)
             receivedMessages.append(.insert(items, timestamp))
         }

From 8acc5277b4dc1208ab74dde21a73c163719f6932 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 13:11:57 +0200
Subject: [PATCH 025/159] Simplify test setup and assertions with a factory
 helper method

---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 38 ++++++++++---------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index b36ff00..4007442 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -18,16 +18,14 @@ class CacheFeedUseCaseTests: XCTestCase {
     
     func test_save_requestsCacheDeletion() {
         let (sut, store) = makeSUT()
-        let items = [uniqueItem()]
-        sut.save(items) { _ in }
+        sut.save(uniqueItems().models) { _ in }
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
     
     func test_save_doesNotRequestCacheInsertionOnDeletionError() {
         let (sut, store) = makeSUT()
-        let items = [uniqueItem()]
         let deletionError = anyNSError()
-        sut.save(items) { _ in }
+        sut.save(uniqueItems().models) { _ in }
         store.completeDeletion(with: deletionError)
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
@@ -35,16 +33,9 @@ class CacheFeedUseCaseTests: XCTestCase {
     func test_save_requestsNewCacheInsertionWithTimestampOnSuccesfulDeletion() {
         let timestamp = Date()
         let (sut, store) = makeSUT(currentDate: { timestamp })
-        let items = [uniqueItem()]
-        let localItems = items.map {
-            LocalFeedItem(
-                id: $0.id,
-                description: $0.description,
-                location: $0.location,
-                imageURL: $0.imageURL
-            )
-        }
-        sut.save(items) { _ in }
+        let items = uniqueItems()
+        let localItems = items.local
+        sut.save(items.models) { _ in }
         store.completeDeletionSuccesfully()
         
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(localItems, timestamp)])
@@ -80,7 +71,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let store = FeedStoreSpy()
         var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
         var receivedResults = [LocalFeedLoader.SaveResult]()
-        sut?.save([uniqueItem()]) { receivedResults.append($0) }
+        sut?.save(uniqueItems().models) { receivedResults.append($0) }
         sut = nil
         store.completeDeletion(with: anyNSError())
         XCTAssertTrue(receivedResults.isEmpty)
@@ -90,7 +81,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let store = FeedStoreSpy()
         var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
         var receivedResults = [LocalFeedLoader.SaveResult]()
-        sut?.save([uniqueItem()]) { receivedResults.append($0) }
+        sut?.save(uniqueItems().models) { receivedResults.append($0) }
         store.completeDeletionSuccesfully()
         sut = nil
         store.completeInsertion(with: anyNSError())
@@ -120,7 +111,7 @@ class CacheFeedUseCaseTests: XCTestCase {
     ) {
         let exp = expectation(description: "Wait for save completion")
         var receivedError: Error?
-        sut.save([uniqueItem()]) { error in
+        sut.save(uniqueItems().models) { error in
             receivedError = error
             exp.fulfill()
         }
@@ -136,6 +127,19 @@ class CacheFeedUseCaseTests: XCTestCase {
         )
     }
     
+    func uniqueItems() -> (models: [FeedItem], local: [LocalFeedItem]) {
+        let models = [uniqueItem(), uniqueItem()]
+        let local = models.map {
+            LocalFeedItem(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                imageURL: $0.imageURL
+            )
+        }
+        return (models, local)
+    }
+    
     func uniqueItem() -> FeedItem {
         return FeedItem(id: UUID(), description: "any", location: "any", imageURL: anyURL())
     }

From 21c324505de86c4722bba01efb410e142c2af530 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 13:23:22 +0200
Subject: [PATCH 026/159] Add `RemoteFeedItem` data transfer representation to
 decouple the items mapper from `FeedItem` data models

---
 .../FeedApi/FeedItemsMapper.swift             | 35 ++++++-------------
 .../FeedApi/RemoteFeedLoader.swift            | 24 ++++++++++++-
 2 files changed, 34 insertions(+), 25 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift b/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
index 22505bd..b462507 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
@@ -6,42 +6,29 @@
 //
 import Foundation
 
+internal struct RemoteFeedItem: Decodable {
+    internal let id: UUID
+    internal let description: String?
+    internal let location: String?
+    internal let image: URL
+}
+
 internal enum FeedItemsMapper {
     
     struct Root: Decodable {
-        let items: [Item]
-        
-        var feed: [FeedItem] {
-            items.map(\.item)
-        }
-    }
-    
-    struct Item: Decodable {
-        let id: UUID
-        let description: String?
-        let location: String?
-        let image: URL
-        
-        var item: FeedItem {
-            FeedItem(
-                id: id,
-                description: description,
-                location: location,
-                imageURL: image)
-        }
+        let items: [RemoteFeedItem]
     }
     
     private static let jsonDecoder = JSONDecoder()
-    
     private static let OK_200 = 200
     
-    internal static func map(_ data: Data, from response: HTTPURLResponse) -> RemoteFeedLoader.Result {
+    internal static func map(_ data: Data, from response: HTTPURLResponse) throws -> [RemoteFeedItem] {
         guard
             response.statusCode == OK_200,
             let root = try? jsonDecoder.decode(Root.self, from: data) else {
-            return .failure(RemoteFeedLoader.Error.invalidData)
+            throw RemoteFeedLoader.Error.invalidData
         }
         
-        return .success(root.feed)
+        return root.items
     }
 }
diff --git a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
index eccd2b0..aa20214 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
@@ -28,11 +28,33 @@ public final class RemoteFeedLoader: FeedLoader {
             guard self != nil else { return }
             switch result {
             case let .success(data, response):
-                completion(FeedItemsMapper.map(data, from: response))
+                completion(Self.map(data, from: response))
             case .failure:
                 completion(.failure(Error.connectivity))
             }
         }
     }
+    
+    private static func map(_ data: Data, from response: HTTPURLResponse) -> Result {
+        do {
+            let items = try FeedItemsMapper.map(data, from: response)
+            return .success(items.toModels())
+        } catch {
+            return .failure(error)
+        }
+    }
 }
 
+
+private extension Array where Element == RemoteFeedItem {
+    func toModels() -> [FeedItem] {
+        return map {
+            FeedItem(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                imageURL: $0.image
+            )
+        }
+    }
+}

From cf6df4ea2b34efa8eb5fcf633a647fe2a47d00f8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 13:25:02 +0200
Subject: [PATCH 027/159] Move `RemoteFeedItem` to its own file

---
 .../EssentialFeed.xcodeproj/project.pbxproj        |  1 +
 .../EssentialFeed/FeedApi/FeedItemsMapper.swift    |  7 +------
 .../EssentialFeed/FeedApi/RemoteFeedItem.swift     | 14 ++++++++++++++
 3 files changed, 16 insertions(+), 6 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index a314055..423d281 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -59,6 +59,7 @@
 			membershipExceptions = (
 				FeedItemsMapper.swift,
 				HTTPClient.swift,
+				RemoteFeedItem.swift,
 				RemoteFeedLoader.swift,
 				URLSessionHTTPClient.swift,
 			);
diff --git a/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift b/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
index b462507..71a6644 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
@@ -6,12 +6,7 @@
 //
 import Foundation
 
-internal struct RemoteFeedItem: Decodable {
-    internal let id: UUID
-    internal let description: String?
-    internal let location: String?
-    internal let image: URL
-}
+
 
 internal enum FeedItemsMapper {
     
diff --git a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift
new file mode 100644
index 0000000..fff12ee
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift
@@ -0,0 +1,14 @@
+//
+//  RemoteFeedItem.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+import Foundation
+
+internal struct RemoteFeedItem: Decodable {
+    internal let id: UUID
+    internal let description: String?
+    internal let location: String?
+    internal let image: URL
+}

From 0436d6f64d5080747afa95f34b166f5992634ff8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 13:25:43 +0200
Subject: [PATCH 028/159] Move `LocalFeedItem` to its own file

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 +++
 .../EssentialFeed/Feed Cache/FeedStore.swift  | 19 +------------
 .../Feed Cache/LocalFeedItem.swift            | 28 +++++++++++++++++++
 3 files changed, 33 insertions(+), 18 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 423d281..e15831b 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -14,6 +14,7 @@
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
 		40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975442D9EA01D009652B5 /* FeedStore.swift */; };
+		40B975492D9EA7A2009652B5 /* LocalFeedItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975482D9EA7A2009652B5 /* LocalFeedItem.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -44,6 +45,7 @@
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
 		40B975442D9EA01D009652B5 /* FeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStore.swift; sourceTree = "<group>"; };
+		40B975482D9EA7A2009652B5 /* LocalFeedItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedItem.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -165,6 +167,7 @@
 			children = (
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
+				40B975482D9EA7A2009652B5 /* LocalFeedItem.swift */,
 			);
 			path = "Feed Cache";
 			sourceTree = "<group>";
@@ -320,6 +323,7 @@
 			files = (
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
 				080EDF0C21B6DAE800813479 /* FeedItem.swift in Sources */,
+				40B975492D9EA7A2009652B5 /* LocalFeedItem.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index ac7a78a..52b4343 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -15,21 +15,4 @@ public protocol FeedStore {
     func insert(_ items: [LocalFeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
 }
 
-public struct LocalFeedItem: Equatable {
-    
-    public let id: UUID
-    public let description: String?
-    public let location: String?
-    public let imageURL: URL
-    
-    public init(
-        id: UUID,
-        description: String?,
-        location: String?,
-        imageURL: URL) {
-        self.id = id
-        self.description = description
-        self.location = location
-        self.imageURL = imageURL
-    }
-}
+
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift
new file mode 100644
index 0000000..ee95721
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift	
@@ -0,0 +1,28 @@
+//
+//  LocalFeedItem.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+
+
+import Foundation
+
+public struct LocalFeedItem: Equatable {
+    
+    public let id: UUID
+    public let description: String?
+    public let location: String?
+    public let imageURL: URL
+    
+    public init(
+        id: UUID,
+        description: String?,
+        location: String?,
+        imageURL: URL) {
+        self.id = id
+        self.description = description
+        self.location = location
+        self.imageURL = imageURL
+    }
+}
\ No newline at end of file

From 6c5628825b15b79ffab52a46ec3dc47f8d5e8cb5 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 13:34:15 +0200
Subject: [PATCH 029/159] Remove references of "items" in favor of "images"
 which is a domain term used by domain experts in the specs

---
 .../EssentialFeed.xcodeproj/project.pbxproj   | 16 ++++-----
 .../EssentialFeed/Feed Cache/FeedStore.swift  |  2 +-
 ...calFeedItem.swift => LocalFeedImage.swift} | 12 +++----
 .../Feed Cache/LocalFeedLoader.swift          | 16 ++++-----
 .../{FeedItem.swift => FeedImage.swift}       |  8 ++---
 .../Feed Feature/FeedLoader.swift             |  2 +-
 .../FeedApi/RemoteFeedLoader.swift            |  6 ++--
 .../EssentialFeedAPIEndToEndTests.swift       | 26 +++++++-------
 .../LoadFeedFromRemoteUseCaseTests.swift      |  6 ++--
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 36 +++++++++----------
 10 files changed, 65 insertions(+), 65 deletions(-)
 rename EssentialFeed/EssentialFeed/Feed Cache/{LocalFeedItem.swift => LocalFeedImage.swift} (72%)
 rename EssentialFeed/EssentialFeed/Feed Feature/{FeedItem.swift => FeedImage.swift} (75%)

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index e15831b..3b16bb0 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -8,13 +8,13 @@
 
 /* Begin PBXBuildFile section */
 		080EDEFB21B6DA7E00813479 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
-		080EDF0C21B6DAE800813479 /* FeedItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedItem.swift */; };
+		080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedImage.swift */; };
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
 		40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975442D9EA01D009652B5 /* FeedStore.swift */; };
-		40B975492D9EA7A2009652B5 /* LocalFeedItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975482D9EA7A2009652B5 /* LocalFeedItem.swift */; };
+		40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -39,13 +39,13 @@
 		080EDEF521B6DA7E00813479 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		080EDEFA21B6DA7E00813479 /* EssentialFeedTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		080EDF0121B6DA7E00813479 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
-		080EDF0B21B6DAE800813479 /* FeedItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedItem.swift; sourceTree = "<group>"; };
+		080EDF0B21B6DAE800813479 /* FeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedImage.swift; sourceTree = "<group>"; };
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
 		40B975442D9EA01D009652B5 /* FeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStore.swift; sourceTree = "<group>"; };
-		40B975482D9EA7A2009652B5 /* LocalFeedItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedItem.swift; sourceTree = "<group>"; };
+		40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedImage.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -148,7 +148,7 @@
 		080EDF1021B6DFA200813479 /* Feed Feature */ = {
 			isa = PBXGroup;
 			children = (
-				080EDF0B21B6DAE800813479 /* FeedItem.swift */,
+				080EDF0B21B6DAE800813479 /* FeedImage.swift */,
 				080EDF0D21B6DCB600813479 /* FeedLoader.swift */,
 			);
 			path = "Feed Feature";
@@ -167,7 +167,7 @@
 			children = (
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
-				40B975482D9EA7A2009652B5 /* LocalFeedItem.swift */,
+				40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */,
 			);
 			path = "Feed Cache";
 			sourceTree = "<group>";
@@ -322,8 +322,8 @@
 			buildActionMask = 2147483647;
 			files = (
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
-				080EDF0C21B6DAE800813479 /* FeedItem.swift in Sources */,
-				40B975492D9EA7A2009652B5 /* LocalFeedItem.swift in Sources */,
+				080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */,
+				40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 52b4343..69a8175 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -12,7 +12,7 @@ public protocol FeedStore {
     typealias InsertionCompletion = (Error?) -> Void
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
-    func insert(_ items: [LocalFeedItem], timestamp: Date, completion: @escaping InsertionCompletion)
+    func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion)
 }
 
 
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift
similarity index 72%
rename from EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift
rename to EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift
index ee95721..b94cfe9 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedItem.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift	
@@ -1,5 +1,5 @@
 //
-//  LocalFeedItem.swift
+//  LocalFeedImage.swift
 //  EssentialFeed
 //
 //  Created by Cristian Felipe Patiño Rojas on 3/4/25.
@@ -8,21 +8,21 @@
 
 import Foundation
 
-public struct LocalFeedItem: Equatable {
+public struct LocalFeedImage: Equatable {
     
     public let id: UUID
     public let description: String?
     public let location: String?
-    public let imageURL: URL
+    public let url: URL
     
     public init(
         id: UUID,
         description: String?,
         location: String?,
-        imageURL: URL) {
+        url: URL) {
         self.id = id
         self.description = description
         self.location = location
-        self.imageURL = imageURL
+        self.url = url
     }
-}
\ No newline at end of file
+}
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 34b0119..ff70e61 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -16,33 +16,33 @@ public final class LocalFeedLoader {
         self.currentDate = currentDate
     }
     
-    public func save(_ items: [FeedItem], completion: @escaping (SaveResult) -> Void) {
+    public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }
             if let cacheDeletionError = error {
                 completion(cacheDeletionError)
             } else {
-                self.cache(items, with: completion)
+                self.cache(feed, with: completion)
             }
         }
     }
     
-    private func cache(_ items: [FeedItem], with completion: @escaping (SaveResult) -> Void) {
-        store.insert(items.toLocal(), timestamp: currentDate())  { [weak self] error in
+    private func cache(_ feed: [FeedImage], with completion: @escaping (SaveResult) -> Void) {
+        store.insert(feed.toLocal(), timestamp: currentDate())  { [weak self] error in
             guard self != nil else { return }
             completion(error)
         }
     }
 }
 
-private extension Array where Element == FeedItem {
-    func toLocal() -> [LocalFeedItem] {
+private extension Array where Element == FeedImage {
+    func toLocal() -> [LocalFeedImage] {
         return map {
-            LocalFeedItem(
+            LocalFeedImage(
                 id: $0.id,
                 description: $0.description,
                 location: $0.location,
-                imageURL: $0.imageURL
+                url: $0.url
             )
         }
     }
diff --git a/EssentialFeed/EssentialFeed/Feed Feature/FeedItem.swift b/EssentialFeed/EssentialFeed/Feed Feature/FeedImage.swift
similarity index 75%
rename from EssentialFeed/EssentialFeed/Feed Feature/FeedItem.swift
rename to EssentialFeed/EssentialFeed/Feed Feature/FeedImage.swift
index 11f5d5d..df7e179 100644
--- a/EssentialFeed/EssentialFeed/Feed Feature/FeedItem.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Feature/FeedImage.swift	
@@ -4,21 +4,21 @@
 
 import Foundation
 
-public struct FeedItem: Equatable {
+public struct FeedImage: Equatable {
     
 	public let id: UUID
 	public let description: String?
 	public let location: String?
-	public let imageURL: URL
+	public let url: URL
     
     public init(
         id: UUID,
         description: String?,
         location: String?,
-        imageURL: URL) {
+        url: URL) {
         self.id = id
         self.description = description
         self.location = location
-        self.imageURL = imageURL
+        self.url = url
     }
 }
diff --git a/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift
index 7f61af7..acd3d92 100644
--- a/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift	
@@ -5,7 +5,7 @@
 import Foundation
 
 public enum LoadFeedResult {
-	case success([FeedItem])
+	case success([FeedImage])
 	case failure(Error)
 }
 
diff --git a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
index aa20214..5f2c838 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
@@ -47,13 +47,13 @@ public final class RemoteFeedLoader: FeedLoader {
 
 
 private extension Array where Element == RemoteFeedItem {
-    func toModels() -> [FeedItem] {
+    func toModels() -> [FeedImage] {
         return map {
-            FeedItem(
+            FeedImage(
                 id: $0.id,
                 description: $0.description,
                 location: $0.location,
-                imageURL: $0.image
+                url: $0.image
             )
         }
     }
diff --git a/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift b/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift
index 9bc4bb2..be50db2 100644
--- a/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift
+++ b/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift
@@ -12,16 +12,16 @@ final class EssentialFeedAPIEndToEndTests: XCTestCase {
     
     func test_endToEndTestServerGETFeedResult_matchesFixedTestAccountData() {
         switch getFeedResult() {
-        case let .success(items)?:
-            XCTAssertEqual(items.count, 8, "Expected 8 items in the test account feed")
-            XCTAssertEqual(items[0], expectedItem(at: 0))
-            XCTAssertEqual(items[1], expectedItem(at: 1))
-            XCTAssertEqual(items[2], expectedItem(at: 2))
-            XCTAssertEqual(items[3], expectedItem(at: 3))
-            XCTAssertEqual(items[4], expectedItem(at: 4))
-            XCTAssertEqual(items[5], expectedItem(at: 5))
-            XCTAssertEqual(items[6], expectedItem(at: 6))
-            XCTAssertEqual(items[7], expectedItem(at: 7))
+        case let .success(imageFeed)?:
+            XCTAssertEqual(imageFeed.count, 8, "Expected 8 images in the test account feed")
+            XCTAssertEqual(imageFeed[0], expectedImage(at: 0))
+            XCTAssertEqual(imageFeed[1], expectedImage(at: 1))
+            XCTAssertEqual(imageFeed[2], expectedImage(at: 2))
+            XCTAssertEqual(imageFeed[3], expectedImage(at: 3))
+            XCTAssertEqual(imageFeed[4], expectedImage(at: 4))
+            XCTAssertEqual(imageFeed[5], expectedImage(at: 5))
+            XCTAssertEqual(imageFeed[6], expectedImage(at: 6))
+            XCTAssertEqual(imageFeed[7], expectedImage(at: 7))
         case let .failure(error)?:
             XCTFail("Expected succesful feed result, got \(error) instead")
         default:
@@ -57,12 +57,12 @@ final class EssentialFeedAPIEndToEndTests: XCTestCase {
     
     // MARK: - Helpers
     
-    private func expectedItem(at index: Int) -> FeedItem {
-        return FeedItem(
+    private func expectedImage(at index: Int) -> FeedImage {
+        return FeedImage(
             id: id(at: index),
             description: description(at: index),
             location: location(at: index),
-            imageURL: imageURL(at: index))
+            url: imageURL(at: index))
     }
     
     private func id(at index: Int) -> UUID {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift
index a09fd5a..03fa678 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift	
@@ -122,12 +122,12 @@ class LoadFeedFromRemoteUseCaseTests: XCTestCase {
         .failure(error)
     }
     
-    private func makeItem(id: UUID, description: String? = nil, location: String? = nil, imageURL: URL) -> (model: FeedItem, json: [String: Any]) {
-        let item = FeedItem(
+    private func makeItem(id: UUID, description: String? = nil, location: String? = nil, imageURL: URL) -> (model: FeedImage, json: [String: Any]) {
+        let item = FeedImage(
             id: id,
             description: description,
             location: location,
-            imageURL: imageURL)
+            url: imageURL)
         let json = [
             "id": id.uuidString,
             "description": description,
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 4007442..5f4bcf3 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -18,14 +18,14 @@ class CacheFeedUseCaseTests: XCTestCase {
     
     func test_save_requestsCacheDeletion() {
         let (sut, store) = makeSUT()
-        sut.save(uniqueItems().models) { _ in }
+        sut.save(uniqueImageFeed().models) { _ in }
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
     
     func test_save_doesNotRequestCacheInsertionOnDeletionError() {
         let (sut, store) = makeSUT()
         let deletionError = anyNSError()
-        sut.save(uniqueItems().models) { _ in }
+        sut.save(uniqueImageFeed().models) { _ in }
         store.completeDeletion(with: deletionError)
         XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed])
     }
@@ -33,12 +33,12 @@ class CacheFeedUseCaseTests: XCTestCase {
     func test_save_requestsNewCacheInsertionWithTimestampOnSuccesfulDeletion() {
         let timestamp = Date()
         let (sut, store) = makeSUT(currentDate: { timestamp })
-        let items = uniqueItems()
-        let localItems = items.local
-        sut.save(items.models) { _ in }
+        let feed = uniqueImageFeed()
+        let localFeed = feed.local
+        sut.save(feed.models) { _ in }
         store.completeDeletionSuccesfully()
         
-        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(localItems, timestamp)])
+        XCTAssertEqual(store.receivedMessages, [.deleteCachedFeed, .insert(localFeed, timestamp)])
     }
     
     func test_save_failsOnDeletionError() {
@@ -71,7 +71,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let store = FeedStoreSpy()
         var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
         var receivedResults = [LocalFeedLoader.SaveResult]()
-        sut?.save(uniqueItems().models) { receivedResults.append($0) }
+        sut?.save(uniqueImageFeed().models) { receivedResults.append($0) }
         sut = nil
         store.completeDeletion(with: anyNSError())
         XCTAssertTrue(receivedResults.isEmpty)
@@ -81,7 +81,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         let store = FeedStoreSpy()
         var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
         var receivedResults = [LocalFeedLoader.SaveResult]()
-        sut?.save(uniqueItems().models) { receivedResults.append($0) }
+        sut?.save(uniqueImageFeed().models) { receivedResults.append($0) }
         store.completeDeletionSuccesfully()
         sut = nil
         store.completeInsertion(with: anyNSError())
@@ -111,7 +111,7 @@ class CacheFeedUseCaseTests: XCTestCase {
     ) {
         let exp = expectation(description: "Wait for save completion")
         var receivedError: Error?
-        sut.save(uniqueItems().models) { error in
+        sut.save(uniqueImageFeed().models) { error in
             receivedError = error
             exp.fulfill()
         }
@@ -127,21 +127,21 @@ class CacheFeedUseCaseTests: XCTestCase {
         )
     }
     
-    func uniqueItems() -> (models: [FeedItem], local: [LocalFeedItem]) {
-        let models = [uniqueItem(), uniqueItem()]
+    func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
+        let models = [uniqueImage(), uniqueImage()]
         let local = models.map {
-            LocalFeedItem(
+            LocalFeedImage(
                 id: $0.id,
                 description: $0.description,
                 location: $0.location,
-                imageURL: $0.imageURL
+                url: $0.url
             )
         }
         return (models, local)
     }
     
-    func uniqueItem() -> FeedItem {
-        return FeedItem(id: UUID(), description: "any", location: "any", imageURL: anyURL())
+    func uniqueImage() -> FeedImage {
+        return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
     }
     
     private func anyURL() -> URL {
@@ -157,7 +157,7 @@ class CacheFeedUseCaseTests: XCTestCase {
         
         enum ReceivedMessage: Equatable {
             case deleteCachedFeed
-            case insert([LocalFeedItem], Date)
+            case insert([LocalFeedImage], Date)
         }
         
         func deleteCachedFeed(completion: @escaping DeletionCompletion) {
@@ -173,9 +173,9 @@ class CacheFeedUseCaseTests: XCTestCase {
             deletionCompletions[index](nil)
         }
         
-        func insert(_ items: [LocalFeedItem], timestamp: Date, completion: @escaping InsertionCompletion) {
+        func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
             insertionCompletions.append(completion)
-            receivedMessages.append(.insert(items, timestamp))
+            receivedMessages.append(.insert(feed, timestamp))
         }
         
         func completeInsertion(with error: Error, at index: Int = 0) {

From 13f3ef5f3786678f321c325b9045b051f9527e68 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:14:23 +0200
Subject: [PATCH 030/159] `LocalFeedLoader` does not message store upon
 creation (before loading the feed from the cache store)

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 ++
 .../LoadFeedFromCacheUseCaseTests.swift       | 68 +++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 3b16bb0..f5bc65b 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -15,6 +15,7 @@
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
 		40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975442D9EA01D009652B5 /* FeedStore.swift */; };
 		40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */; };
+		40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -46,6 +47,7 @@
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
 		40B975442D9EA01D009652B5 /* FeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStore.swift; sourceTree = "<group>"; };
 		40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedImage.swift; sourceTree = "<group>"; };
+		40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoadFeedFromCacheUseCaseTests.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -157,6 +159,7 @@
 		40B975392D9E7AD3009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
+				40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */,
 				40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */,
 			);
 			path = "Feed Cache";
@@ -334,6 +337,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
+				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
new file mode 100644
index 0000000..6f25315
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -0,0 +1,68 @@
+//
+//  LoadFeedFromCacheUseCaseTests.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+
+import XCTest
+import EssentialFeed
+
+class LoadFeedFromCacheUseCaseTests: XCTestCase {
+    
+    func test_doesNotMessageStoreUponCreation() {
+        let (_, store) = makeSUT()
+        XCTAssertEqual(store.receivedMessages, [])
+    }
+    
+    // MARK: - Helpers
+    
+    private func makeSUT(
+        currentDate: @escaping () -> Date = Date.init,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) -> (sut: LocalFeedLoader, store: FeedStoreSpy) {
+        let store = FeedStoreSpy()
+        let sut = LocalFeedLoader(store: store, currentDate: currentDate)
+        trackForMemoryLeaks(store, file: file, line: line)
+        trackForMemoryLeaks(sut, file: file, line: line)
+        return (sut, store)
+    }
+    
+    private class FeedStoreSpy: FeedStore {
+        private var deletionCompletions = [DeletionCompletion]()
+        private var insertionCompletions = [InsertionCompletion]()
+        private(set) var receivedMessages = [ReceivedMessage]()
+        
+        enum ReceivedMessage: Equatable {
+            case deleteCachedFeed
+            case insert([LocalFeedImage], Date)
+        }
+        
+        func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+            deletionCompletions.append(completion)
+            receivedMessages.append(.deleteCachedFeed)
+        }
+        
+        func completeDeletion(with error: Error, at index: Int = 0) {
+            deletionCompletions[index](error)
+        }
+        
+        func completeDeletionSuccesfully(at index: Int = 0) {
+            deletionCompletions[index](nil)
+        }
+        
+        func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+            insertionCompletions.append(completion)
+            receivedMessages.append(.insert(feed, timestamp))
+        }
+        
+        func completeInsertion(with error: Error, at index: Int = 0) {
+            insertionCompletions[index](error)
+        }
+        
+        func completeInsertionSuccesfully(at index: Int = 0) {
+            insertionCompletions[index](nil)
+        }
+    }
+}

From 43ac6f4095c56addcd01f3bb12f51017fc14f9fc Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:16:15 +0200
Subject: [PATCH 031/159] Extract `FeedCacheSpy` into a shared scope to remove
 duplication

---
 .../EssentialFeed.xcodeproj/project.pbxproj   | 12 +++++
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 39 +--------------
 .../Feed Cache/Helpers/FeedStoreSpy.swift     | 47 +++++++++++++++++++
 .../LoadFeedFromCacheUseCaseTests.swift       | 37 ---------------
 4 files changed, 60 insertions(+), 75 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index f5bc65b..4285979 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -16,6 +16,7 @@
 		40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975442D9EA01D009652B5 /* FeedStore.swift */; };
 		40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */; };
 		40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */; };
+		40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9754D2D9EC15A009652B5 /* FeedStoreSpy.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -48,6 +49,7 @@
 		40B975442D9EA01D009652B5 /* FeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStore.swift; sourceTree = "<group>"; };
 		40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedImage.swift; sourceTree = "<group>"; };
 		40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoadFeedFromCacheUseCaseTests.swift; sourceTree = "<group>"; };
+		40B9754D2D9EC15A009652B5 /* FeedStoreSpy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpy.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -159,6 +161,7 @@
 		40B975392D9E7AD3009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
+				40B9754C2D9EC147009652B5 /* Helpers */,
 				40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */,
 				40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */,
 			);
@@ -175,6 +178,14 @@
 			path = "Feed Cache";
 			sourceTree = "<group>";
 		};
+		40B9754C2D9EC147009652B5 /* Helpers */ = {
+			isa = PBXGroup;
+			children = (
+				40B9754D2D9EC15A009652B5 /* FeedStoreSpy.swift */,
+			);
+			path = Helpers;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXHeadersBuildPhase section */
@@ -336,6 +347,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
 				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
 			);
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 5f4bcf3..dab3309 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -148,42 +148,5 @@ class CacheFeedUseCaseTests: XCTestCase {
         URL(string: "http://any-url.com")!
     }
     
-    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
-    
-    private class FeedStoreSpy: FeedStore {
-        private var deletionCompletions = [DeletionCompletion]()
-        private var insertionCompletions = [InsertionCompletion]()
-        private(set) var receivedMessages = [ReceivedMessage]()
-        
-        enum ReceivedMessage: Equatable {
-            case deleteCachedFeed
-            case insert([LocalFeedImage], Date)
-        }
-        
-        func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-            deletionCompletions.append(completion)
-            receivedMessages.append(.deleteCachedFeed)
-        }
-        
-        func completeDeletion(with error: Error, at index: Int = 0) {
-            deletionCompletions[index](error)
-        }
-        
-        func completeDeletionSuccesfully(at index: Int = 0) {
-            deletionCompletions[index](nil)
-        }
-        
-        func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-            insertionCompletions.append(completion)
-            receivedMessages.append(.insert(feed, timestamp))
-        }
-        
-        func completeInsertion(with error: Error, at index: Int = 0) {
-            insertionCompletions[index](error)
-        }
-        
-        func completeInsertionSuccesfully(at index: Int = 0) {
-            insertionCompletions[index](nil)
-        }
-    }
+    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }    
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
new file mode 100644
index 0000000..82327bb
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -0,0 +1,47 @@
+//
+//  FeedStoreSpy.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 3/4/25.
+//
+
+
+import XCTest
+import EssentialFeed
+
+class FeedStoreSpy: FeedStore {
+        private var deletionCompletions = [DeletionCompletion]()
+        private var insertionCompletions = [InsertionCompletion]()
+        private(set) var receivedMessages = [ReceivedMessage]()
+        
+        enum ReceivedMessage: Equatable {
+            case deleteCachedFeed
+            case insert([LocalFeedImage], Date)
+        }
+        
+        func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+            deletionCompletions.append(completion)
+            receivedMessages.append(.deleteCachedFeed)
+        }
+        
+        func completeDeletion(with error: Error, at index: Int = 0) {
+            deletionCompletions[index](error)
+        }
+        
+        func completeDeletionSuccesfully(at index: Int = 0) {
+            deletionCompletions[index](nil)
+        }
+        
+        func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+            insertionCompletions.append(completion)
+            receivedMessages.append(.insert(feed, timestamp))
+        }
+        
+        func completeInsertion(with error: Error, at index: Int = 0) {
+            insertionCompletions[index](error)
+        }
+        
+        func completeInsertionSuccesfully(at index: Int = 0) {
+            insertionCompletions[index](nil)
+        }
+    }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 6f25315..5c2a214 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -28,41 +28,4 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         trackForMemoryLeaks(sut, file: file, line: line)
         return (sut, store)
     }
-    
-    private class FeedStoreSpy: FeedStore {
-        private var deletionCompletions = [DeletionCompletion]()
-        private var insertionCompletions = [InsertionCompletion]()
-        private(set) var receivedMessages = [ReceivedMessage]()
-        
-        enum ReceivedMessage: Equatable {
-            case deleteCachedFeed
-            case insert([LocalFeedImage], Date)
-        }
-        
-        func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-            deletionCompletions.append(completion)
-            receivedMessages.append(.deleteCachedFeed)
-        }
-        
-        func completeDeletion(with error: Error, at index: Int = 0) {
-            deletionCompletions[index](error)
-        }
-        
-        func completeDeletionSuccesfully(at index: Int = 0) {
-            deletionCompletions[index](nil)
-        }
-        
-        func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-            insertionCompletions.append(completion)
-            receivedMessages.append(.insert(feed, timestamp))
-        }
-        
-        func completeInsertion(with error: Error, at index: Int = 0) {
-            insertionCompletions[index](error)
-        }
-        
-        func completeInsertionSuccesfully(at index: Int = 0) {
-            insertionCompletions[index](nil)
-        }
-    }
 }

From 660e80161aca60314e654d2fbbb93e2f810b8fa1 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:19:48 +0200
Subject: [PATCH 032/159] Load command requests cache retrieval

---
 .../EssentialFeed/Feed Cache/FeedStore.swift  |  1 +
 .../Feed Cache/LocalFeedLoader.swift          |  4 +
 .../Feed Cache/Helpers/FeedStoreSpy.swift     | 74 ++++++++++---------
 .../LoadFeedFromCacheUseCaseTests.swift       |  6 ++
 4 files changed, 51 insertions(+), 34 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 69a8175..9615a77 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -13,6 +13,7 @@ public protocol FeedStore {
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion)
+    func retrieve()
 }
 
 
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index ff70e61..67c3256 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -16,6 +16,10 @@ public final class LocalFeedLoader {
         self.currentDate = currentDate
     }
     
+    public func load() {
+        store.retrieve()
+    }
+    
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index 82327bb..54d56e2 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -10,38 +10,44 @@ import XCTest
 import EssentialFeed
 
 class FeedStoreSpy: FeedStore {
-        private var deletionCompletions = [DeletionCompletion]()
-        private var insertionCompletions = [InsertionCompletion]()
-        private(set) var receivedMessages = [ReceivedMessage]()
-        
-        enum ReceivedMessage: Equatable {
-            case deleteCachedFeed
-            case insert([LocalFeedImage], Date)
-        }
-        
-        func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-            deletionCompletions.append(completion)
-            receivedMessages.append(.deleteCachedFeed)
-        }
-        
-        func completeDeletion(with error: Error, at index: Int = 0) {
-            deletionCompletions[index](error)
-        }
-        
-        func completeDeletionSuccesfully(at index: Int = 0) {
-            deletionCompletions[index](nil)
-        }
-        
-        func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-            insertionCompletions.append(completion)
-            receivedMessages.append(.insert(feed, timestamp))
-        }
-        
-        func completeInsertion(with error: Error, at index: Int = 0) {
-            insertionCompletions[index](error)
-        }
-        
-        func completeInsertionSuccesfully(at index: Int = 0) {
-            insertionCompletions[index](nil)
-        }
+    private var deletionCompletions = [DeletionCompletion]()
+    private var insertionCompletions = [InsertionCompletion]()
+    private(set) var receivedMessages = [ReceivedMessage]()
+    
+    enum ReceivedMessage: Equatable {
+        case deleteCachedFeed
+        case insert([LocalFeedImage], Date)
+        case retrieve
     }
+    
+    func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+        deletionCompletions.append(completion)
+        receivedMessages.append(.deleteCachedFeed)
+    }
+    
+    func completeDeletion(with error: Error, at index: Int = 0) {
+        deletionCompletions[index](error)
+    }
+    
+    func completeDeletionSuccesfully(at index: Int = 0) {
+        deletionCompletions[index](nil)
+    }
+    
+    
+    func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+        insertionCompletions.append(completion)
+        receivedMessages.append(.insert(feed, timestamp))
+    }
+    
+    func completeInsertion(with error: Error, at index: Int = 0) {
+        insertionCompletions[index](error)
+    }
+    
+    func completeInsertionSuccesfully(at index: Int = 0) {
+        insertionCompletions[index](nil)
+    }
+    
+    func retrieve() {
+        receivedMessages.append(.retrieve)
+    }
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 5c2a214..a4ed601 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -15,6 +15,12 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [])
     }
     
+    func test_load_requestsCacheRetrieval() {
+        let (sut, store) = makeSUT()
+        sut.load()
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From ff82695274d4420eb3fe3d187880df34f743d480 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:27:48 +0200
Subject: [PATCH 033/159] Load command fails on retrieval error

---
 .../EssentialFeed/Feed Cache/FeedStore.swift  |  3 ++-
 .../Feed Cache/LocalFeedLoader.swift          |  4 ++--
 .../Feed Cache/Helpers/FeedStoreSpy.swift     |  9 +++++++-
 .../LoadFeedFromCacheUseCaseTests.swift       | 21 ++++++++++++++++++-
 4 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 9615a77..1425707 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -10,10 +10,11 @@ import Foundation
 public protocol FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     typealias InsertionCompletion = (Error?) -> Void
+    typealias RetrievalCompletion = (Error?) -> Void
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion)
-    func retrieve()
+    func retrieve(completion: @escaping RetrievalCompletion)
 }
 
 
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 67c3256..1d5d2c3 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -16,8 +16,8 @@ public final class LocalFeedLoader {
         self.currentDate = currentDate
     }
     
-    public func load() {
-        store.retrieve()
+    public func load(completion: @escaping (Error?) -> Void) {
+        store.retrieve(completion: completion)
     }
     
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index 54d56e2..87e60ab 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -12,6 +12,8 @@ import EssentialFeed
 class FeedStoreSpy: FeedStore {
     private var deletionCompletions = [DeletionCompletion]()
     private var insertionCompletions = [InsertionCompletion]()
+    private var retrievalCompletions = [RetrievalCompletion]()
+    
     private(set) var receivedMessages = [ReceivedMessage]()
     
     enum ReceivedMessage: Equatable {
@@ -47,7 +49,12 @@ class FeedStoreSpy: FeedStore {
         insertionCompletions[index](nil)
     }
     
-    func retrieve() {
+    func retrieve(completion: @escaping RetrievalCompletion) {
+        retrievalCompletions.append(completion)
         receivedMessages.append(.retrieve)
     }
+    
+    func completeRetrieval(with error: Error, at index: Int = 0) {
+        retrievalCompletions[index](error)
+    }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index a4ed601..3c3a924 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -17,10 +17,27 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
     
     func test_load_requestsCacheRetrieval() {
         let (sut, store) = makeSUT()
-        sut.load()
+        sut.load() { _ in }
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
+    func test_load_failsOnRetrievalError() {
+        let (sut, store) = makeSUT()
+        let retrievalError = anyNSError()
+        var receivedError: Error?
+        let exp = expectation(description: "Wait for load completion")
+        
+        sut.load { error in
+            receivedError = error
+            exp.fulfill()
+        }
+        
+        store.completeRetrieval(with: retrievalError)
+        wait(for: [exp], timeout: 1.0)
+        
+        XCTAssertEqual(receivedError as NSError?, retrievalError)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(
@@ -34,4 +51,6 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         trackForMemoryLeaks(sut, file: file, line: line)
         return (sut, store)
     }
+    
+    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
 }

From eb710bf9b80c4338d725e8baee5091423f33f389 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:32:42 +0200
Subject: [PATCH 034/159] Replace load command completion to return a result
 type rather than an optional error

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift       | 9 +++++++--
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift       | 8 ++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 1d5d2c3..7cf5673 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -11,13 +11,18 @@ public final class LocalFeedLoader {
     private let currentDate: () -> Date
     
     public typealias SaveResult = Error?
+    public typealias LoadResult = LoadFeedResult
     public init(store: FeedStore, currentDate: @escaping () -> Date) {
         self.store = store
         self.currentDate = currentDate
     }
     
-    public func load(completion: @escaping (Error?) -> Void) {
-        store.retrieve(completion: completion)
+    public func load(completion: @escaping (LoadResult) -> Void) {
+        store.retrieve { error in
+            if let error = error {
+                completion(.failure(error))
+            }
+        }
     }
     
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 3c3a924..24d5fa5 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -27,8 +27,12 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         var receivedError: Error?
         let exp = expectation(description: "Wait for load completion")
         
-        sut.load { error in
-            receivedError = error
+        sut.load { result in
+            switch result {
+            case let .failure(error):
+                receivedError = error
+            default: XCTFail("Expected error, got \(result) instead")
+            }
             exp.fulfill()
         }
         

From f8510e43156e0372a34c871866719e9c3eab3208 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:36:38 +0200
Subject: [PATCH 035/159] Load command delivers no images on empty cache

---
 .../Feed Cache/LocalFeedLoader.swift          |  2 ++
 .../Feed Cache/Helpers/FeedStoreSpy.swift     |  4 ++++
 .../LoadFeedFromCacheUseCaseTests.swift       | 20 +++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 7cf5673..b30d4e5 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -21,6 +21,8 @@ public final class LocalFeedLoader {
         store.retrieve { error in
             if let error = error {
                 completion(.failure(error))
+            } else {
+                completion(.success([]))
             }
         }
     }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index 87e60ab..63f7429 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -57,4 +57,8 @@ class FeedStoreSpy: FeedStore {
     func completeRetrieval(with error: Error, at index: Int = 0) {
         retrievalCompletions[index](error)
     }
+    
+    func completeRetrievalWithEmptyCache(at index: Int = 0) {
+        retrievalCompletions[index](nil)
+    }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 24d5fa5..807758b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -42,6 +42,26 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(receivedError as NSError?, retrievalError)
     }
     
+    func test_load_deliversNoImagesOnEmptyCache() {
+        let (sut, store) = makeSUT()
+        var receivedImages: [FeedImage]?
+        let exp = expectation(description: "Wait for load completion")
+        
+        sut.load { result in
+            exp.fulfill()
+            switch result {
+            case .success(let images):
+                receivedImages = images
+            default: XCTFail("Expected success, got \(result) instead")
+            }
+        }
+        
+        store.completeRetrievalWithEmptyCache()
+        wait(for: [exp], timeout: 1.0)
+        
+        XCTAssertEqual(receivedImages, [])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From c10236eb52f9d2b0efe0360648c70c8d719c9432 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:43:52 +0200
Subject: [PATCH 036/159] Extract duplicated test code into a shared helper
 method

---
 .../LoadFeedFromCacheUseCaseTests.swift       | 62 ++++++++++---------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 807758b..b6a8438 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -24,42 +24,18 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
     func test_load_failsOnRetrievalError() {
         let (sut, store) = makeSUT()
         let retrievalError = anyNSError()
-        var receivedError: Error?
-        let exp = expectation(description: "Wait for load completion")
-        
-        sut.load { result in
-            switch result {
-            case let .failure(error):
-                receivedError = error
-            default: XCTFail("Expected error, got \(result) instead")
-            }
-            exp.fulfill()
-        }
-        
-        store.completeRetrieval(with: retrievalError)
-        wait(for: [exp], timeout: 1.0)
         
-        XCTAssertEqual(receivedError as NSError?, retrievalError)
+        expect(sut, toCompleteWith: .failure(retrievalError), when: {
+            store.completeRetrieval(with: retrievalError)
+        })
     }
     
     func test_load_deliversNoImagesOnEmptyCache() {
         let (sut, store) = makeSUT()
-        var receivedImages: [FeedImage]?
-        let exp = expectation(description: "Wait for load completion")
-        
-        sut.load { result in
-            exp.fulfill()
-            switch result {
-            case .success(let images):
-                receivedImages = images
-            default: XCTFail("Expected success, got \(result) instead")
-            }
-        }
         
-        store.completeRetrievalWithEmptyCache()
-        wait(for: [exp], timeout: 1.0)
-        
-        XCTAssertEqual(receivedImages, [])
+        expect(sut, toCompleteWith: .success([]), when: {
+            store.completeRetrievalWithEmptyCache()
+        })
     }
     
     // MARK: - Helpers
@@ -76,5 +52,31 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         return (sut, store)
     }
     
+    private func expect(
+        _ sut: LocalFeedLoader,
+        toCompleteWith expectedResult: LocalFeedLoader.LoadResult,
+        when action: () -> Void,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let exp = expectation(description: "Wait for load completion")
+        
+        sut.load { receivedResult in
+            exp.fulfill()
+            switch (receivedResult, expectedResult) {
+            case let (.success(receivedImages), .success(expectedImages)):
+                XCTAssertEqual(receivedImages, expectedImages, file: file, line: line)
+            case let (.failure(receivedError as NSError), .failure(expectedError as NSError)):
+                XCTAssertEqual(receivedError, expectedError, file: file, line: line)
+            default:
+                XCTFail("Expected result \(expectedResult), got \(receivedResult) instead", file: file, line: line)
+            }
+            
+        }
+        
+        action()
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
 }

From fb65fc0c3b4103b921a61f869847916488d2ab2d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 15:55:01 +0200
Subject: [PATCH 037/159] Load commnd delivers cached images on less than seven
 days old cache

---
 .../EssentialFeed/Feed Cache/FeedStore.swift  |  8 +++-
 .../Feed Cache/LocalFeedLoader.swift          | 22 ++++++++--
 .../Feed Cache/Helpers/FeedStoreSpy.swift     |  8 +++-
 .../LoadFeedFromCacheUseCaseTests.swift       | 41 +++++++++++++++++++
 4 files changed, 73 insertions(+), 6 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 1425707..8810996 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -7,10 +7,16 @@
 
 import Foundation
 
+public enum RetrieveCachedFeedResult {
+    case empty
+    case found(feed: [LocalFeedImage], timestamp: Date)
+    case failure(Error)
+}
+
 public protocol FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     typealias InsertionCompletion = (Error?) -> Void
-    typealias RetrievalCompletion = (Error?) -> Void
+    typealias RetrievalCompletion = (RetrieveCachedFeedResult) -> Void
     
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion)
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index b30d4e5..f3a8691 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -18,11 +18,14 @@ public final class LocalFeedLoader {
     }
     
     public func load(completion: @escaping (LoadResult) -> Void) {
-        store.retrieve { error in
-            if let error = error {
+        store.retrieve { result in
+            switch result {
+            case let .failure(error):
                 completion(.failure(error))
-            } else {
+            case .empty:
                 completion(.success([]))
+            case let .found(feed, _):
+                completion(.success(feed.toModels()))
             }
         }
     }
@@ -58,3 +61,16 @@ private extension Array where Element == FeedImage {
         }
     }
 }
+
+private extension Array where Element == LocalFeedImage {
+    func toModels() -> [FeedImage] {
+        return map {
+            FeedImage(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                url: $0.url
+            )
+        }
+    }
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index 63f7429..d142bce 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -55,10 +55,14 @@ class FeedStoreSpy: FeedStore {
     }
     
     func completeRetrieval(with error: Error, at index: Int = 0) {
-        retrievalCompletions[index](error)
+        retrievalCompletions[index](.failure(error))
     }
     
     func completeRetrievalWithEmptyCache(at index: Int = 0) {
-        retrievalCompletions[index](nil)
+        retrievalCompletions[index](.empty)
+    }
+    
+    func completeRetrieval(with feed: [LocalFeedImage], timestamp: Date, at index: Int = 0) {
+        retrievalCompletions[index](.found(feed: feed, timestamp: timestamp))
     }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index b6a8438..957b384 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -38,6 +38,17 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         })
     }
     
+    func test_load_deliversCachedImagesOnLessThanSevenDaysOldCache() {
+        let feed = uniqueImageFeed()
+        let fixedCurrentDate = Date()
+        let lessThanSevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7).adding(seconds: -1)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        expect(sut, toCompleteWith: .success(feed.models), when: {
+            store.completeRetrieval(with: feed.local, timestamp: lessThanSevenDaysOldTimestamp)
+        })
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(
@@ -79,4 +90,34 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
     }
     
     private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
+    private func anyURL() -> URL {
+        URL(string: "http://any-url.com")!
+    }
+    
+    func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
+        let models = [uniqueImage(), uniqueImage()]
+        let local = models.map {
+            LocalFeedImage(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                url: $0.url
+            )
+        }
+        return (models, local)
+    }
+    
+    func uniqueImage() -> FeedImage {
+        return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
+    }
+}
+
+private extension Date {
+    func adding(days: Int) -> Date {
+        return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
+    }
+    
+    func adding(seconds: TimeInterval) -> Date {
+        return self + seconds
+    }
 }

From 871880d5c17b31dc3c2fc04b62ab8be3b4a2c057 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 16:08:14 +0200
Subject: [PATCH 038/159] Load command delivers no images on seven days old
 cache

---
 .../Feed Cache/LocalFeedLoader.swift            | 17 +++++++++++++----
 .../LoadFeedFromCacheUseCaseTests.swift         | 17 ++++++++++++++++-
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index f3a8691..c2f1994 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -18,18 +18,27 @@ public final class LocalFeedLoader {
     }
     
     public func load(completion: @escaping (LoadResult) -> Void) {
-        store.retrieve { result in
+        store.retrieve { [unowned self] result in
             switch result {
             case let .failure(error):
                 completion(.failure(error))
-            case .empty:
-                completion(.success([]))
-            case let .found(feed, _):
+                
+            case let .found(feed, timestamp) where self.validate(timestamp):
                 completion(.success(feed.toModels()))
+            case .found, .empty:
+                completion(.success([]))
             }
         }
     }
     
+    private func validate(_ timestamp: Date) -> Bool {
+        let calendar = Calendar(identifier: .gregorian)
+        guard let maxCacheAge = calendar.date(byAdding: .day, value: 7, to: timestamp) else {
+            return false
+        }
+        return currentDate() < maxCacheAge
+    }
+    
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 957b384..45c452c 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -41,10 +41,25 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
     func test_load_deliversCachedImagesOnLessThanSevenDaysOldCache() {
         let feed = uniqueImageFeed()
         let fixedCurrentDate = Date()
-        let lessThanSevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7).adding(seconds: -1)
+        let lessThanSevenDaysOldTimestamp = fixedCurrentDate
+            .adding(days: -7)
+            .adding(seconds: 1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         expect(sut, toCompleteWith: .success(feed.models), when: {
+            store.completeRetrieval(
+                with: feed.local,
+                timestamp: lessThanSevenDaysOldTimestamp)
+        })
+    }
+    
+    func test_load_deliversNoImagesOnSevenDaysOldCache() {
+        let feed = uniqueImageFeed()
+        let fixedCurrentDate = Date()
+        let lessThanSevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        expect(sut, toCompleteWith: .success([]), when: {
             store.completeRetrieval(with: feed.local, timestamp: lessThanSevenDaysOldTimestamp)
         })
     }

From 88e9a17ccd3d3905cb687a059b468254681c6d08 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 16:15:07 +0200
Subject: [PATCH 039/159] Extract local members into properties

---
 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index c2f1994..483045e 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -9,6 +9,7 @@ import Foundation
 public final class LocalFeedLoader {
     private let store: FeedStore
     private let currentDate: () -> Date
+    private let calendar = Calendar(identifier: .gregorian)
     
     public typealias SaveResult = Error?
     public typealias LoadResult = LoadFeedResult
@@ -31,9 +32,9 @@ public final class LocalFeedLoader {
         }
     }
     
+    private var maxCacheAgeInDays: Int { return 7 }
     private func validate(_ timestamp: Date) -> Bool {
-        let calendar = Calendar(identifier: .gregorian)
-        guard let maxCacheAge = calendar.date(byAdding: .day, value: 7, to: timestamp) else {
+        guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
             return false
         }
         return currentDate() < maxCacheAge

From 7b70f80de0ec868ba3eb4476a20b8372564cac5d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Thu, 3 Apr 2025 16:16:26 +0200
Subject: [PATCH 040/159] Load command delivers no images on more than seven
 days old cache

---
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift  | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 45c452c..0bf8f23 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -64,6 +64,19 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         })
     }
     
+    func test_load_deliversNoImagesOnMoreThanSevenDaysOldCache() {
+        let feed = uniqueImageFeed()
+        let fixedCurrentDate = Date()
+        let moreThanSevenDaysOldTimestamp = fixedCurrentDate
+            .adding(days: -7)
+            .adding(seconds: -1)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        expect(sut, toCompleteWith: .success([]), when: {
+            store.completeRetrieval(with: feed.local, timestamp: moreThanSevenDaysOldTimestamp)
+        })
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 7a60ea93db8d32c26fafd0e93f77986acc4f14fb Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 10:36:37 +0200
Subject: [PATCH 041/159] Deletes cache on retrieval error

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift         | 1 +
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift         | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 483045e..dbe3275 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -22,6 +22,7 @@ public final class LocalFeedLoader {
         store.retrieve { [unowned self] result in
             switch result {
             case let .failure(error):
+                self.store.deleteCachedFeed { _ in }
                 completion(.failure(error))
                 
             case let .found(feed, timestamp) where self.validate(timestamp):
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 0bf8f23..eccbf4c 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -77,6 +77,13 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         })
     }
     
+    func test_load_deletesCacheOnRetrievalError() {
+        let (sut, store) = makeSUT()
+        sut.load { _ in }
+        store.completeRetrieval(with: anyNSError())
+        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 03e54100eeeb0df78d1cd6ce9bc5178c5a6fb930 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 10:37:38 +0200
Subject: [PATCH 042/159] Load command does not delete cache when cache is
 already empty

---
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift         | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index eccbf4c..ab069b7 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -84,6 +84,13 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
     }
     
+    func test_load_doesNotDeleteCacheOnEmptyCache() {
+        let (sut, store) = makeSUT()
+        sut.load { _ in }
+        store.completeRetrievalWithEmptyCache()
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 61701777de6094f5efdbe547051e256c28ceff24 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 10:41:00 +0200
Subject: [PATCH 043/159] Load command does not delete less than seven days old
 cache

---
 .../LoadFeedFromCacheUseCaseTests.swift           | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index ab069b7..6eab50d 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -91,6 +91,21 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
+    func test_load_doesNotDeleteCacheOnLessThanSevenDaysOldCache() {
+        let fixedCurrentDate = Date()
+        let lessThanSevenDaysOldTimestamp = fixedCurrentDate
+            .adding(days: -7)
+            .adding(seconds: 1)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        sut.load { _ in }
+        store.completeRetrieval(
+            with: uniqueImageFeed().local,
+            timestamp: lessThanSevenDaysOldTimestamp
+        )
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From d01a9bcfb8fff244b44de105c02822cfbe423842 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 10:44:24 +0200
Subject: [PATCH 044/159] Load command deletes seven days old cache upon
 retrieval

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift     |  5 ++++-
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift     | 10 ++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index dbe3275..fb6ac74 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -27,7 +27,10 @@ public final class LocalFeedLoader {
                 
             case let .found(feed, timestamp) where self.validate(timestamp):
                 completion(.success(feed.toModels()))
-            case .found, .empty:
+            case .found:
+                self.store.deleteCachedFeed { _ in }
+                completion(.success([]))
+            case .empty:
                 completion(.success([]))
             }
         }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 6eab50d..1d1c1d1 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -106,6 +106,16 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
+    func test_load_deletesCacheOnSevenDaysOldCache() {
+        let fixedCurrentDate = Date()
+        let sevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        
+        sut.load { _ in }
+        store.completeRetrieval(with: uniqueImageFeed().local, timestamp: sevenDaysOldTimestamp)
+        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 6bfe842b008f5ac412c49c054bea67c44d58140e Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 10:46:17 +0200
Subject: [PATCH 045/159] Load command deletes more than seven days old cache
 upon retrieval

---
 .../LoadFeedFromCacheUseCaseTests.swift         | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 1d1c1d1..5d7e338 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -116,6 +116,23 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
     }
     
+    func test_load_deletesCacheOnMoreThanSevenDaysOldCache() {
+        let fixedCurrentDate = Date()
+        let moreThanSevenDaysOldCacheTimestamp = fixedCurrentDate
+            .adding(days: -7)
+            .adding(seconds: -1)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        
+        sut.load { _ in }
+        store.completeRetrieval(
+            with: uniqueImageFeed().local,
+            timestamp: moreThanSevenDaysOldCacheTimestamp
+        )
+        
+        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From a301ea77807cb217464e8f48f23c29a57b7f9679 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 10:58:35 +0200
Subject: [PATCH 046/159] Load command does not delive a load result after the
 instance has been deallocated to prevent unexpected behaviors in clients code

---
 .../Feed Cache/LocalFeedLoader.swift              |  3 ++-
 .../LoadFeedFromCacheUseCaseTests.swift           | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index fb6ac74..015376d 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -19,7 +19,8 @@ public final class LocalFeedLoader {
     }
     
     public func load(completion: @escaping (LoadResult) -> Void) {
-        store.retrieve { [unowned self] result in
+        store.retrieve { [weak self] result in
+            guard let self else { return }
             switch result {
             case let .failure(error):
                 self.store.deleteCachedFeed { _ in }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 5d7e338..be4ee2b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -133,6 +133,21 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
     }
     
+    func test_load_doesNotDeliverResultAfterSUTInstanceHasBeenDeallocated() {
+        let store = FeedStoreSpy()
+        var sut: LocalFeedLoader? = LocalFeedLoader(
+            store: store,
+            currentDate: Date.init
+        )
+        
+        var receivedResults = [LocalFeedLoader.LoadResult]()
+        sut?.load { receivedResults.append($0) }
+        
+        sut = nil
+        store.completeRetrievalWithEmptyCache()
+        XCTAssertTrue(receivedResults.isEmpty)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(

From 63125315e11e7b04c40042dd006cd78418540170 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:06:36 +0200
Subject: [PATCH 047/159] LocalFeedLoader does not message the store upon
 creation before  validating the cached feed

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 +++
 .../ValidateFeedCacheUseCaseTests.swift       | 30 +++++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 4285979..5a01095 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -10,6 +10,7 @@
 		080EDEFB21B6DA7E00813479 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedImage.swift */; };
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
+		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -43,6 +44,7 @@
 		080EDF0121B6DA7E00813479 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		080EDF0B21B6DAE800813479 /* FeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedImage.swift; sourceTree = "<group>"; };
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
+		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -164,6 +166,7 @@
 				40B9754C2D9EC147009652B5 /* Helpers */,
 				40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */,
 				40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */,
+				407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */,
 			);
 			path = "Feed Cache";
 			sourceTree = "<group>";
@@ -347,6 +350,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */,
 				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
 				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
new file mode 100644
index 0000000..9e4f951
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -0,0 +1,30 @@
+//
+//  ValidateFeedCacheUseCaseTests.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
+//
+
+import XCTest
+import EssentialFeed
+
+class ValidateFeedCacheUseCaseTests: XCTestCase {
+   
+    func test_doesNotMessageStoreUponCreation() {
+        let (_, store) = makeSUT()
+        XCTAssertEqual(store.receivedMessages, [])
+    }
+    
+    // MARK: - Helpers
+    private func makeSUT(
+        currentDate: @escaping () -> Date = Date.init,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) -> (sut: LocalFeedLoader, store: FeedStoreSpy) {
+        let store = FeedStoreSpy()
+        let sut = LocalFeedLoader(store: store, currentDate: currentDate)
+        trackForMemoryLeaks(store, file: file, line: line)
+        trackForMemoryLeaks(sut, file: file, line: line)
+        return (sut, store)
+    }
+}

From 4e19f751419e8925a19e6153144d27df2330647d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:13:53 +0200
Subject: [PATCH 048/159] Extract cache deletion side-effect on retrieval error
 from the load method to the validate cache method

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift     |  6 +++++-
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift     |  4 ++--
 .../Feed Cache/ValidateFeedCacheUseCaseTests.swift     | 10 ++++++++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 015376d..3bde08c 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -23,7 +23,6 @@ public final class LocalFeedLoader {
             guard let self else { return }
             switch result {
             case let .failure(error):
-                self.store.deleteCachedFeed { _ in }
                 completion(.failure(error))
                 
             case let .found(feed, timestamp) where self.validate(timestamp):
@@ -37,6 +36,11 @@ public final class LocalFeedLoader {
         }
     }
     
+    public func validateCache() {
+        store.retrieve { _ in }
+        store.deleteCachedFeed { _ in }
+    }
+    
     private var maxCacheAgeInDays: Int { return 7 }
     private func validate(_ timestamp: Date) -> Bool {
         guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index be4ee2b..ef93f86 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -77,11 +77,11 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         })
     }
     
-    func test_load_deletesCacheOnRetrievalError() {
+    func test_load_hasNoSideEffectsOnRetrievalError() {
         let (sut, store) = makeSUT()
         sut.load { _ in }
         store.completeRetrieval(with: anyNSError())
-        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
     func test_load_doesNotDeleteCacheOnEmptyCache() {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index 9e4f951..91c4e52 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -15,6 +15,14 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [])
     }
     
+    func test_validateCache_deletesCacheOnRetrievalError() {
+        let (sut, store) = makeSUT()
+        sut.validateCache()
+        store.completeRetrieval(with: anyNSError())
+        
+        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         currentDate: @escaping () -> Date = Date.init,
@@ -27,4 +35,6 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         trackForMemoryLeaks(sut, file: file, line: line)
         return (sut, store)
     }
+    
+    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
 }

From c161ac343cd9afb1cf9da7abe42137f1421ee9a2 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:15:56 +0200
Subject: [PATCH 049/159] Validate cache command does not delete cache when
 cache is already empty

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift       | 9 +++++++--
 .../Feed Cache/LoadFeedFromCacheUseCaseTests.swift       | 2 +-
 .../Feed Cache/ValidateFeedCacheUseCaseTests.swift       | 7 +++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 3bde08c..d5f3bf3 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -37,8 +37,13 @@ public final class LocalFeedLoader {
     }
     
     public func validateCache() {
-        store.retrieve { _ in }
-        store.deleteCachedFeed { _ in }
+        store.retrieve { [unowned self] result in
+            switch result {
+            case .failure:
+                self.store.deleteCachedFeed { _ in }
+            default: break
+            }
+        }
     }
     
     private var maxCacheAgeInDays: Int { return 7 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index ef93f86..af749b0 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -84,7 +84,7 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_doesNotDeleteCacheOnEmptyCache() {
+    func test_load_hasNoSideEffectsOnEmptyCache() {
         let (sut, store) = makeSUT()
         sut.load { _ in }
         store.completeRetrievalWithEmptyCache()
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index 91c4e52..ac75bc4 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -23,6 +23,13 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
     }
     
+    func test_validateCache_doesNotDeleteCacheOnEmptyCache() {
+        let (sut, store) = makeSUT()
+        sut.validateCache()
+        store.completeRetrievalWithEmptyCache()
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         currentDate: @escaping () -> Date = Date.init,

From 4bb811352cacc9c6a1394f02d06dc77fdc70fa61 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:18:20 +0200
Subject: [PATCH 050/159] Validate cache command does not delete less than
 seven days old cache

---
 .../LoadFeedFromCacheUseCaseTests.swift       |  2 +-
 .../ValidateFeedCacheUseCaseTests.swift       | 46 +++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index af749b0..27bee4b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -91,7 +91,7 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_doesNotDeleteCacheOnLessThanSevenDaysOldCache() {
+    func test_load_hasNoSideEffectsOnLessThanSevenDaysOldCache() {
         let fixedCurrentDate = Date()
         let lessThanSevenDaysOldTimestamp = fixedCurrentDate
             .adding(days: -7)
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index ac75bc4..bbba8b9 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -30,6 +30,21 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
+    func test_validateCache_doesNotDeleteCacheOnLessThanSevenDaysOldCache() {
+        let fixedCurrentDate = Date()
+        let lessThanSevenDaysOldTimestamp = fixedCurrentDate
+            .adding(days: -7)
+            .adding(seconds: 1)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        sut.validateCache()
+        store.completeRetrieval(
+            with: uniqueImageFeed().local,
+            timestamp: lessThanSevenDaysOldTimestamp
+        )
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         currentDate: @escaping () -> Date = Date.init,
@@ -44,4 +59,35 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
     }
     
     private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
+    
+    func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
+        let models = [uniqueImage(), uniqueImage()]
+        let local = models.map {
+            LocalFeedImage(
+                id: $0.id,
+                description: $0.description,
+                location: $0.location,
+                url: $0.url
+            )
+        }
+        return (models, local)
+    }
+    
+    func uniqueImage() -> FeedImage {
+        return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
+    }
+    
+    private func anyURL() -> URL {
+        URL(string: "http://any-url.com")!
+    }
+}
+
+private extension Date {
+    func adding(days: Int) -> Date {
+        return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
+    }
+    
+    func adding(seconds: TimeInterval) -> Date {
+        return self + seconds
+    }
 }

From d48c2b3faf1d1f49d52267b5a8cd3542cf3eac83 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:25:13 +0200
Subject: [PATCH 051/159] Extract duplicated test helpers into a shared scope

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  5 +++
 .../Feed Api/URLSessionHTTPClientTests.swift  |  5 ---
 .../Feed Cache/CacheFeedUseCaseTests.swift    | 23 ------------
 .../Helpers/FeedCacheTestHelpers.swift        | 37 +++++++++++++++++++
 .../LoadFeedFromCacheUseCaseTests.swift       | 32 ----------------
 .../ValidateFeedCacheUseCaseTests.swift       | 35 +-----------------
 .../Helpers/SharedTestHelpers.swift           | 15 ++++++++
 7 files changed, 58 insertions(+), 94 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift
 create mode 100644 EssentialFeed/EssentialFeedTests/Helpers/SharedTestHelpers.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 5a01095..defda19 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -11,6 +11,7 @@
 		080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedImage.swift */; };
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
+		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -45,6 +46,7 @@
 		080EDF0B21B6DAE800813479 /* FeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedImage.swift; sourceTree = "<group>"; };
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
+		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -58,6 +60,7 @@
 		40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */ = {
 			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
 			membershipExceptions = (
+				SharedTestHelpers.swift,
 				"XCTestCase+MemoryLeakTrackingHelper.swift",
 			);
 			target = 40B002442CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */;
@@ -185,6 +188,7 @@
 			isa = PBXGroup;
 			children = (
 				40B9754D2D9EC15A009652B5 /* FeedStoreSpy.swift */,
+				407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */,
 			);
 			path = Helpers;
 			sourceTree = "<group>";
@@ -354,6 +358,7 @@
 				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
 				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
+				407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift b/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift
index 4868054..6e36dba 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift	
@@ -169,15 +169,10 @@ class URLSessionHTTPClientTests: XCTestCase {
     }
     
     private func anyData() -> Data { Data("any data".utf8) }
-    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
     
     private func nonHTTPURLResponse() -> URLResponse { URLResponse() }
     private func anyHTTPURLResponse() -> HTTPURLResponse { HTTPURLResponse() }
     
-    private func anyURL() -> URL {
-        URL(string: "http://any-url.com")!
-    }
-    
     private class URLProtocolStub: URLProtocol {
         private static var stub: Stub?
         private static var requestObserver: ((URLRequest) -> Void)?
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index dab3309..1319e81 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -126,27 +126,4 @@ class CacheFeedUseCaseTests: XCTestCase {
             line: line
         )
     }
-    
-    func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
-        let models = [uniqueImage(), uniqueImage()]
-        let local = models.map {
-            LocalFeedImage(
-                id: $0.id,
-                description: $0.description,
-                location: $0.location,
-                url: $0.url
-            )
-        }
-        return (models, local)
-    }
-    
-    func uniqueImage() -> FeedImage {
-        return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
-    }
-    
-    private func anyURL() -> URL {
-        URL(string: "http://any-url.com")!
-    }
-    
-    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }    
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift
new file mode 100644
index 0000000..8ea825a
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
@@ -0,0 +1,37 @@
+//
+//  FeedCacheTestHelpers.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
+//
+
+import Foundation
+import EssentialFeed
+
+func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
+    let models = [uniqueImage(), uniqueImage()]
+    let local = models.map {
+        LocalFeedImage(
+            id: $0.id,
+            description: $0.description,
+            location: $0.location,
+            url: $0.url
+        )
+    }
+    return (models, local)
+}
+
+func uniqueImage() -> FeedImage {
+    return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
+}
+
+extension Date {
+    func adding(days: Int) -> Date {
+        return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
+    }
+    
+    func adding(seconds: TimeInterval) -> Date {
+        return self + seconds
+    }
+}
+
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 27bee4b..b193788 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -187,36 +187,4 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         action()
         wait(for: [exp], timeout: 1.0)
     }
-    
-    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
-    private func anyURL() -> URL {
-        URL(string: "http://any-url.com")!
-    }
-    
-    func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
-        let models = [uniqueImage(), uniqueImage()]
-        let local = models.map {
-            LocalFeedImage(
-                id: $0.id,
-                description: $0.description,
-                location: $0.location,
-                url: $0.url
-            )
-        }
-        return (models, local)
-    }
-    
-    func uniqueImage() -> FeedImage {
-        return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
-    }
-}
-
-private extension Date {
-    func adding(days: Int) -> Date {
-        return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
-    }
-    
-    func adding(seconds: TimeInterval) -> Date {
-        return self + seconds
-    }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index bbba8b9..15d2d3b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -9,7 +9,7 @@ import XCTest
 import EssentialFeed
 
 class ValidateFeedCacheUseCaseTests: XCTestCase {
-   
+    
     func test_doesNotMessageStoreUponCreation() {
         let (_, store) = makeSUT()
         XCTAssertEqual(store.receivedMessages, [])
@@ -57,37 +57,4 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         trackForMemoryLeaks(sut, file: file, line: line)
         return (sut, store)
     }
-    
-    private func anyNSError() -> NSError { NSError(domain: "any error", code: 0) }
-    
-    func uniqueImageFeed() -> (models: [FeedImage], local: [LocalFeedImage]) {
-        let models = [uniqueImage(), uniqueImage()]
-        let local = models.map {
-            LocalFeedImage(
-                id: $0.id,
-                description: $0.description,
-                location: $0.location,
-                url: $0.url
-            )
-        }
-        return (models, local)
-    }
-    
-    func uniqueImage() -> FeedImage {
-        return FeedImage(id: UUID(), description: "any", location: "any", url: anyURL())
-    }
-    
-    private func anyURL() -> URL {
-        URL(string: "http://any-url.com")!
-    }
-}
-
-private extension Date {
-    func adding(days: Int) -> Date {
-        return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
-    }
-    
-    func adding(seconds: TimeInterval) -> Date {
-        return self + seconds
-    }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Helpers/SharedTestHelpers.swift b/EssentialFeed/EssentialFeedTests/Helpers/SharedTestHelpers.swift
new file mode 100644
index 0000000..0044fad
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Helpers/SharedTestHelpers.swift
@@ -0,0 +1,15 @@
+//
+//  SharedTestHelpers.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
+//
+
+import Foundation
+
+func anyNSError() -> NSError { NSError(domain: "any error", code: 0)
+}
+
+func anyURL() -> URL {
+    URL(string: "http://any-url.com")!
+}

From 27573447b89af8c23a10109e1986c74a0e4eaac0 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:36:06 +0200
Subject: [PATCH 052/159] Extract cache deletion side-effects on expired cache
 from the load method to the validate cache method

---
 .../Feed Cache/LocalFeedLoader.swift          |  5 ++--
 .../LoadFeedFromCacheUseCaseTests.swift       |  8 ++---
 .../ValidateFeedCacheUseCaseTests.swift       | 29 ++++++++++++++++++-
 3 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index d5f3bf3..37beac8 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -28,7 +28,6 @@ public final class LocalFeedLoader {
             case let .found(feed, timestamp) where self.validate(timestamp):
                 completion(.success(feed.toModels()))
             case .found:
-                self.store.deleteCachedFeed { _ in }
                 completion(.success([]))
             case .empty:
                 completion(.success([]))
@@ -39,9 +38,11 @@ public final class LocalFeedLoader {
     public func validateCache() {
         store.retrieve { [unowned self] result in
             switch result {
+            case let .found(_, timestamp) where !self.validate(timestamp):
+                self.store.deleteCachedFeed { _ in }
             case .failure:
                 self.store.deleteCachedFeed { _ in }
-            default: break
+            case .empty, .found: break
             }
         }
     }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index b193788..2723875 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -106,17 +106,17 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_deletesCacheOnSevenDaysOldCache() {
+    func test_load_hasNoSideEffectsOnSevenDaysOldCache() {
         let fixedCurrentDate = Date()
         let sevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         
         sut.load { _ in }
         store.completeRetrieval(with: uniqueImageFeed().local, timestamp: sevenDaysOldTimestamp)
-        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_deletesCacheOnMoreThanSevenDaysOldCache() {
+    func test_load_hasNoSideEffectsOnMoreThanSevenDaysOldCache() {
         let fixedCurrentDate = Date()
         let moreThanSevenDaysOldCacheTimestamp = fixedCurrentDate
             .adding(days: -7)
@@ -130,7 +130,7 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
             timestamp: moreThanSevenDaysOldCacheTimestamp
         )
         
-        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
     func test_load_doesNotDeliverResultAfterSUTInstanceHasBeenDeallocated() {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index 15d2d3b..05cb014 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -30,7 +30,7 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_validateCache_doesNotDeleteCacheOnLessThanSevenDaysOldCache() {
+    func test_validateCache_doesNotDeleteLessThanSevenDaysOldCache() {
         let fixedCurrentDate = Date()
         let lessThanSevenDaysOldTimestamp = fixedCurrentDate
             .adding(days: -7)
@@ -45,6 +45,33 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
+    func test_validateCache_deletesSevenDaysOldCache() {
+        let fixedCurrentDate = Date()
+        let sevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        
+        sut.validateCache()
+        store.completeRetrieval(with: uniqueImageFeed().local, timestamp: sevenDaysOldTimestamp)
+        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+    }
+    
+    func test_validateCache_deletesMoreThanSevenDaysOldCache() {
+        let fixedCurrentDate = Date()
+        let moreThanSevenDaysOldCacheTimestamp = fixedCurrentDate
+            .adding(days: -7)
+            .adding(seconds: -1)
+        
+        let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
+        
+        sut.validateCache()
+        store.completeRetrieval(
+            with: uniqueImageFeed().local,
+            timestamp: moreThanSevenDaysOldCacheTimestamp
+        )
+        
+        XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         currentDate: @escaping () -> Date = Date.init,

From 637a60330b75f4242989013fb36bdba8be5fc8b9 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:38:41 +0200
Subject: [PATCH 053/159] Validate cache command  does not delete cache after
 instance has been deallocated

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift    |  3 ++-
 .../Feed Cache/ValidateFeedCacheUseCaseTests.swift    | 11 +++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 37beac8..e81cc52 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -36,7 +36,8 @@ public final class LocalFeedLoader {
     }
     
     public func validateCache() {
-        store.retrieve { [unowned self] result in
+        store.retrieve { [weak self] result in
+            guard let self else { return }
             switch result {
             case let .found(_, timestamp) where !self.validate(timestamp):
                 self.store.deleteCachedFeed { _ in }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index 05cb014..2ccf77d 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -72,6 +72,17 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
     }
     
+    func test_validateCache_doesNotDeleteInvalidCacheAfterSUTInstanceHasBeenDeallocated() {
+        let store = FeedStoreSpy()
+        var sut: LocalFeedLoader? = LocalFeedLoader(store: store, currentDate: Date.init)
+        
+        sut?.validateCache()
+        sut = nil
+        store.completeRetrieval(with: anyNSError())
+        
+        XCTAssertEqual(store.receivedMessages, [.retrieve])
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         currentDate: @escaping () -> Date = Date.init,

From f4b56b0562a3f80482a847577a8def27c19ce301 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:39:30 +0200
Subject: [PATCH 054/159] Group cases to remove duplication

---
 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index e81cc52..402d1c8 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -27,9 +27,7 @@ public final class LocalFeedLoader {
                 
             case let .found(feed, timestamp) where self.validate(timestamp):
                 completion(.success(feed.toModels()))
-            case .found:
-                completion(.success([]))
-            case .empty:
+            case .found, .empty:
                 completion(.success([]))
             }
         }

From 7709baf4d9a5bfb65332d07563a85f1c8b664bd9 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:41:47 +0200
Subject: [PATCH 055/159] Segment functionnalities into extensions

---
 .../Feed Cache/LocalFeedLoader.swift          | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 402d1c8..fa85663 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -18,6 +18,16 @@ public final class LocalFeedLoader {
         self.currentDate = currentDate
     }
     
+    private var maxCacheAgeInDays: Int { return 7 }
+    private func validate(_ timestamp: Date) -> Bool {
+        guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
+            return false
+        }
+        return currentDate() < maxCacheAge
+    }
+}
+   
+extension LocalFeedLoader {
     public func load(completion: @escaping (LoadResult) -> Void) {
         store.retrieve { [weak self] result in
             guard let self else { return }
@@ -32,7 +42,9 @@ public final class LocalFeedLoader {
             }
         }
     }
-    
+}
+
+extension LocalFeedLoader {
     public func validateCache() {
         store.retrieve { [weak self] result in
             guard let self else { return }
@@ -45,15 +57,9 @@ public final class LocalFeedLoader {
             }
         }
     }
-    
-    private var maxCacheAgeInDays: Int { return 7 }
-    private func validate(_ timestamp: Date) -> Bool {
-        guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
-            return false
-        }
-        return currentDate() < maxCacheAge
-    }
-    
+}
+
+extension LocalFeedLoader {
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }

From c520a63105c947c00782db573f9f2360b5ed12ba Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:42:14 +0200
Subject: [PATCH 056/159] Make LocalFeedLoader conform to FeedLoader protocol

---
 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index fa85663..66b2374 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -6,7 +6,7 @@
 //
 import Foundation
 
-public final class LocalFeedLoader {
+public final class LocalFeedLoader: FeedLoader {
     private let store: FeedStore
     private let currentDate: () -> Date
     private let calendar = Calendar(identifier: .gregorian)

From 08aea38b54971ba3a677108a21119bc01a5ef187 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 11:42:55 +0200
Subject: [PATCH 057/159] Move typealiases to pertinent segments

---
 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 66b2374..3b8725b 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -11,8 +11,6 @@ public final class LocalFeedLoader: FeedLoader {
     private let currentDate: () -> Date
     private let calendar = Calendar(identifier: .gregorian)
     
-    public typealias SaveResult = Error?
-    public typealias LoadResult = LoadFeedResult
     public init(store: FeedStore, currentDate: @escaping () -> Date) {
         self.store = store
         self.currentDate = currentDate
@@ -28,6 +26,7 @@ public final class LocalFeedLoader: FeedLoader {
 }
    
 extension LocalFeedLoader {
+    public typealias LoadResult = LoadFeedResult
     public func load(completion: @escaping (LoadResult) -> Void) {
         store.retrieve { [weak self] result in
             guard let self else { return }
@@ -60,6 +59,7 @@ extension LocalFeedLoader {
 }
 
 extension LocalFeedLoader {
+    public typealias SaveResult = Error?
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
         store.deleteCachedFeed { [weak self] error in
             guard let self else { return }

From 1eb6bc6091f2170e3851f9e2d1482477a6eacaf6 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:17:56 +0200
Subject: [PATCH 058/159] Extract cache validation policy into the new
 `FeedCachePolicy` type

---
 .../Feed Cache/LocalFeedLoader.swift          | 23 +++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 3b8725b..f6fade9 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -6,24 +6,33 @@
 //
 import Foundation
 
-public final class LocalFeedLoader: FeedLoader {
-    private let store: FeedStore
+private final class FeedCachePolicy {
     private let currentDate: () -> Date
     private let calendar = Calendar(identifier: .gregorian)
     
-    public init(store: FeedStore, currentDate: @escaping () -> Date) {
-        self.store = store
+    init(currentDate: @escaping () -> Date) {
         self.currentDate = currentDate
     }
     
     private var maxCacheAgeInDays: Int { return 7 }
-    private func validate(_ timestamp: Date) -> Bool {
+    
+    func validate(_ timestamp: Date) -> Bool {
         guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
             return false
         }
         return currentDate() < maxCacheAge
     }
 }
+public final class LocalFeedLoader: FeedLoader {
+    private let store: FeedStore
+    private let currentDate: () -> Date
+    private let cachePolicy: FeedCachePolicy
+    public init(store: FeedStore, currentDate: @escaping () -> Date) {
+        self.store = store
+        self.currentDate = currentDate
+        self.cachePolicy = FeedCachePolicy(currentDate: currentDate)
+    }
+}
    
 extension LocalFeedLoader {
     public typealias LoadResult = LoadFeedResult
@@ -34,7 +43,7 @@ extension LocalFeedLoader {
             case let .failure(error):
                 completion(.failure(error))
                 
-            case let .found(feed, timestamp) where self.validate(timestamp):
+            case let .found(feed, timestamp) where self.cachePolicy.validate(timestamp):
                 completion(.success(feed.toModels()))
             case .found, .empty:
                 completion(.success([]))
@@ -48,7 +57,7 @@ extension LocalFeedLoader {
         store.retrieve { [weak self] result in
             guard let self else { return }
             switch result {
-            case let .found(_, timestamp) where !self.validate(timestamp):
+            case let .found(_, timestamp) where !self.cachePolicy.validate(timestamp):
                 self.store.deleteCachedFeed { _ in }
             case .failure:
                 self.store.deleteCachedFeed { _ in }

From dabbcd657759660561743de9206fbc4dfdf89a9f Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:20:57 +0200
Subject: [PATCH 059/159] Make the feed cache policy a pure type with no side
 effects (deterministic)

---
 .../Feed Cache/LocalFeedLoader.swift             | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index f6fade9..b27801a 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -7,30 +7,24 @@
 import Foundation
 
 private final class FeedCachePolicy {
-    private let currentDate: () -> Date
     private let calendar = Calendar(identifier: .gregorian)
     
-    init(currentDate: @escaping () -> Date) {
-        self.currentDate = currentDate
-    }
-    
     private var maxCacheAgeInDays: Int { return 7 }
     
-    func validate(_ timestamp: Date) -> Bool {
+    func validate(_ timestamp: Date, against date: Date) -> Bool {
         guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
             return false
         }
-        return currentDate() < maxCacheAge
+        return date < maxCacheAge
     }
 }
 public final class LocalFeedLoader: FeedLoader {
     private let store: FeedStore
     private let currentDate: () -> Date
-    private let cachePolicy: FeedCachePolicy
+    private let cachePolicy = FeedCachePolicy()
     public init(store: FeedStore, currentDate: @escaping () -> Date) {
         self.store = store
         self.currentDate = currentDate
-        self.cachePolicy = FeedCachePolicy(currentDate: currentDate)
     }
 }
    
@@ -43,7 +37,7 @@ extension LocalFeedLoader {
             case let .failure(error):
                 completion(.failure(error))
                 
-            case let .found(feed, timestamp) where self.cachePolicy.validate(timestamp):
+            case let .found(feed, timestamp) where self.cachePolicy.validate(timestamp, against: currentDate()):
                 completion(.success(feed.toModels()))
             case .found, .empty:
                 completion(.success([]))
@@ -57,7 +51,7 @@ extension LocalFeedLoader {
         store.retrieve { [weak self] result in
             guard let self else { return }
             switch result {
-            case let .found(_, timestamp) where !self.cachePolicy.validate(timestamp):
+            case let .found(_, timestamp) where !self.cachePolicy.validate(timestamp, against: currentDate()):
                 self.store.deleteCachedFeed { _ in }
             case .failure:
                 self.store.deleteCachedFeed { _ in }

From c244c0b3516869937fb05331322bb1c662187c7e Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:28:08 +0200
Subject: [PATCH 060/159] Make feed cache policy static since it doesn't keep
 any state

---
 .../EssentialFeed/Feed Cache/LocalFeedLoader.swift  | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index b27801a..a622328 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -7,21 +7,22 @@
 import Foundation
 
 private final class FeedCachePolicy {
-    private let calendar = Calendar(identifier: .gregorian)
+    private static let calendar = Calendar(identifier: .gregorian)
+    private static var maxCacheAgeInDays: Int { return 7 }
     
-    private var maxCacheAgeInDays: Int { return 7 }
+    private init() {}
     
-    func validate(_ timestamp: Date, against date: Date) -> Bool {
+    static func validate(_ timestamp: Date, against date: Date) -> Bool {
         guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
             return false
         }
         return date < maxCacheAge
     }
 }
+
 public final class LocalFeedLoader: FeedLoader {
     private let store: FeedStore
     private let currentDate: () -> Date
-    private let cachePolicy = FeedCachePolicy()
     public init(store: FeedStore, currentDate: @escaping () -> Date) {
         self.store = store
         self.currentDate = currentDate
@@ -37,7 +38,7 @@ extension LocalFeedLoader {
             case let .failure(error):
                 completion(.failure(error))
                 
-            case let .found(feed, timestamp) where self.cachePolicy.validate(timestamp, against: currentDate()):
+            case let .found(feed, timestamp) where FeedCachePolicy.validate(timestamp, against: currentDate()):
                 completion(.success(feed.toModels()))
             case .found, .empty:
                 completion(.success([]))
@@ -51,7 +52,7 @@ extension LocalFeedLoader {
         store.retrieve { [weak self] result in
             guard let self else { return }
             switch result {
-            case let .found(_, timestamp) where !self.cachePolicy.validate(timestamp, against: currentDate()):
+            case let .found(_, timestamp) where !FeedCachePolicy.validate(timestamp, against: currentDate()):
                 self.store.deleteCachedFeed { _ in }
             case .failure:
                 self.store.deleteCachedFeed { _ in }

From 453e1d14f32e23d2e683956688b2c2c5100dd824 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:30:41 +0200
Subject: [PATCH 061/159] Move FeedCachePolicy to its own file

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 ++++
 .../Feed Cache/FeedCachePolicy.swift          | 20 +++++++++++++++++++
 .../Feed Cache/LocalFeedLoader.swift          | 14 +------------
 3 files changed, 25 insertions(+), 13 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index defda19..5bfbbb6 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -12,6 +12,7 @@
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
+		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -47,6 +48,7 @@
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
+		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -178,6 +180,7 @@
 			isa = PBXGroup;
 			children = (
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
+				407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
 				40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */,
 			);
@@ -345,6 +348,7 @@
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
 				080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */,
 				40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */,
+				407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift
new file mode 100644
index 0000000..4b5450e
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift	
@@ -0,0 +1,20 @@
+//
+//  FeedCachePolicy.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
+//
+
+import Foundation
+
+internal final class FeedCachePolicy {
+    private static let calendar = Calendar(identifier: .gregorian)
+    private static var maxCacheAgeInDays: Int { return 7 }
+    private init() {}
+    static func validate(_ timestamp: Date, against date: Date) -> Bool {
+        guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
+            return false
+        }
+        return date < maxCacheAge
+    }
+}
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index a622328..191acf1 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -6,19 +6,7 @@
 //
 import Foundation
 
-private final class FeedCachePolicy {
-    private static let calendar = Calendar(identifier: .gregorian)
-    private static var maxCacheAgeInDays: Int { return 7 }
-    
-    private init() {}
-    
-    static func validate(_ timestamp: Date, against date: Date) -> Bool {
-        guard let maxCacheAge = calendar.date(byAdding: .day, value: maxCacheAgeInDays, to: timestamp) else {
-            return false
-        }
-        return date < maxCacheAge
-    }
-}
+
 
 public final class LocalFeedLoader: FeedLoader {
     private let store: FeedStore

From d1f479c4a55f7249c5cb6308625d7d0fbad7cd8d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:38:37 +0200
Subject: [PATCH 062/159] Hide cache expiration details from tests with a new
 DSL method to protect tests from breaking changes

---
 .../Helpers/FeedCacheTestHelpers.swift        |  6 ++-
 .../LoadFeedFromCacheUseCaseTests.swift       | 44 +++++++++----------
 .../ValidateFeedCacheUseCaseTests.swift       | 22 +++++-----
 3 files changed, 38 insertions(+), 34 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift
index 8ea825a..18c3ce8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
@@ -26,7 +26,11 @@ func uniqueImage() -> FeedImage {
 }
 
 extension Date {
-    func adding(days: Int) -> Date {
+    func minusFeedCacheMaxAge() -> Date {
+        return adding(days: -7)
+    }
+    
+    private func adding(days: Int) -> Date {
         return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
     }
     
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift
index 2723875..43ce6af 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/LoadFeedFromCacheUseCaseTests.swift	
@@ -38,42 +38,42 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         })
     }
     
-    func test_load_deliversCachedImagesOnLessThanSevenDaysOldCache() {
+    func test_load_deliversCachedImagesOnNonExpiredCache() {
         let feed = uniqueImageFeed()
         let fixedCurrentDate = Date()
-        let lessThanSevenDaysOldTimestamp = fixedCurrentDate
-            .adding(days: -7)
+        let nonExpiredTimestamp = fixedCurrentDate
+            .minusFeedCacheMaxAge()
             .adding(seconds: 1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         expect(sut, toCompleteWith: .success(feed.models), when: {
             store.completeRetrieval(
                 with: feed.local,
-                timestamp: lessThanSevenDaysOldTimestamp)
+                timestamp: nonExpiredTimestamp)
         })
     }
     
-    func test_load_deliversNoImagesOnSevenDaysOldCache() {
+    func test_load_deliversNoImagesOnCacheExpiration() {
         let feed = uniqueImageFeed()
         let fixedCurrentDate = Date()
-        let lessThanSevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
+        let expirationTimestamp = fixedCurrentDate.minusFeedCacheMaxAge()
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         expect(sut, toCompleteWith: .success([]), when: {
-            store.completeRetrieval(with: feed.local, timestamp: lessThanSevenDaysOldTimestamp)
+            store.completeRetrieval(with: feed.local, timestamp: expirationTimestamp)
         })
     }
     
-    func test_load_deliversNoImagesOnMoreThanSevenDaysOldCache() {
+    func test_load_deliversNoImagesOnExpiredCache() {
         let feed = uniqueImageFeed()
         let fixedCurrentDate = Date()
-        let moreThanSevenDaysOldTimestamp = fixedCurrentDate
-            .adding(days: -7)
+        let expiredTimestamp = fixedCurrentDate
+            .minusFeedCacheMaxAge()
             .adding(seconds: -1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         expect(sut, toCompleteWith: .success([]), when: {
-            store.completeRetrieval(with: feed.local, timestamp: moreThanSevenDaysOldTimestamp)
+            store.completeRetrieval(with: feed.local, timestamp: expiredTimestamp)
         })
     }
     
@@ -91,35 +91,35 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_hasNoSideEffectsOnLessThanSevenDaysOldCache() {
+    func test_load_hasNoSideEffectsOnNonExpiredCache() {
         let fixedCurrentDate = Date()
-        let lessThanSevenDaysOldTimestamp = fixedCurrentDate
-            .adding(days: -7)
+        let nonExpiredTimestamp = fixedCurrentDate
+            .minusFeedCacheMaxAge()
             .adding(seconds: 1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         sut.load { _ in }
         store.completeRetrieval(
             with: uniqueImageFeed().local,
-            timestamp: lessThanSevenDaysOldTimestamp
+            timestamp: nonExpiredTimestamp
         )
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_hasNoSideEffectsOnSevenDaysOldCache() {
+    func test_load_hasNoSideEffectsOnCacheExpiration() {
         let fixedCurrentDate = Date()
-        let sevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
+        let expirationTimestamp = fixedCurrentDate.minusFeedCacheMaxAge()
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         
         sut.load { _ in }
-        store.completeRetrieval(with: uniqueImageFeed().local, timestamp: sevenDaysOldTimestamp)
+        store.completeRetrieval(with: uniqueImageFeed().local, timestamp: expirationTimestamp)
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_load_hasNoSideEffectsOnMoreThanSevenDaysOldCache() {
+    func test_load_hasNoSideEffectsOnExpiredCache() {
         let fixedCurrentDate = Date()
-        let moreThanSevenDaysOldCacheTimestamp = fixedCurrentDate
-            .adding(days: -7)
+        let expiredTimestamp = fixedCurrentDate
+            .minusFeedCacheMaxAge()
             .adding(seconds: -1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
@@ -127,7 +127,7 @@ class LoadFeedFromCacheUseCaseTests: XCTestCase {
         sut.load { _ in }
         store.completeRetrieval(
             with: uniqueImageFeed().local,
-            timestamp: moreThanSevenDaysOldCacheTimestamp
+            timestamp: expiredTimestamp
         )
         
         XCTAssertEqual(store.receivedMessages, [.retrieve])
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift
index 2ccf77d..258a5e5 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/ValidateFeedCacheUseCaseTests.swift	
@@ -30,35 +30,35 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_validateCache_doesNotDeleteLessThanSevenDaysOldCache() {
+    func test_validateCache_doesNotDeleteNonExpiredCache() {
         let fixedCurrentDate = Date()
-        let lessThanSevenDaysOldTimestamp = fixedCurrentDate
-            .adding(days: -7)
+        let nonExpiredTimestamp = fixedCurrentDate
+            .minusFeedCacheMaxAge()
             .adding(seconds: 1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         sut.validateCache()
         store.completeRetrieval(
             with: uniqueImageFeed().local,
-            timestamp: lessThanSevenDaysOldTimestamp
+            timestamp: nonExpiredTimestamp
         )
         XCTAssertEqual(store.receivedMessages, [.retrieve])
     }
     
-    func test_validateCache_deletesSevenDaysOldCache() {
+    func test_validateCache_deletesCacheOnExpiration() {
         let fixedCurrentDate = Date()
-        let sevenDaysOldTimestamp = fixedCurrentDate.adding(days: -7)
+        let expirationTimestamp = fixedCurrentDate.minusFeedCacheMaxAge()
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
         
         sut.validateCache()
-        store.completeRetrieval(with: uniqueImageFeed().local, timestamp: sevenDaysOldTimestamp)
+        store.completeRetrieval(with: uniqueImageFeed().local, timestamp: expirationTimestamp)
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])
     }
     
-    func test_validateCache_deletesMoreThanSevenDaysOldCache() {
+    func test_validateCache_deletesExpiredCache() {
         let fixedCurrentDate = Date()
-        let moreThanSevenDaysOldCacheTimestamp = fixedCurrentDate
-            .adding(days: -7)
+        let expiredTimestamp = fixedCurrentDate
+            .minusFeedCacheMaxAge()
             .adding(seconds: -1)
         
         let (sut, store) = makeSUT(currentDate: { fixedCurrentDate })
@@ -66,7 +66,7 @@ class ValidateFeedCacheUseCaseTests: XCTestCase {
         sut.validateCache()
         store.completeRetrieval(
             with: uniqueImageFeed().local,
-            timestamp: moreThanSevenDaysOldCacheTimestamp
+            timestamp: expiredTimestamp
         )
         
         XCTAssertEqual(store.receivedMessages, [.retrieve, .deleteCachedFeed])

From d7b6cf29dfbf42478c9795922bdebee89e84f2db Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:39:38 +0200
Subject: [PATCH 063/159] Move feed cache max age (7) days to a computer var to
 clarify intent in code

---
 .../Feed Cache/Helpers/FeedCacheTestHelpers.swift             | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift
index 18c3ce8..c462849 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
@@ -27,9 +27,11 @@ func uniqueImage() -> FeedImage {
 
 extension Date {
     func minusFeedCacheMaxAge() -> Date {
-        return adding(days: -7)
+        return adding(days: -feedCacheMaxAgeInDays)
     }
     
+    private var feedCacheMaxAgeInDays: Int { 7 }
+    
     private func adding(days: Int) -> Date {
         return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
     }

From 1d282a4ebc138495efd6ed6665a104a0b5a18d76 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 12:40:51 +0200
Subject: [PATCH 064/159] Separate date extension helpers into two distinct
 context to clarify their scope (one is a cache policy specific DSL, the other
 is just a reusable DSL helper)

---
 .../Feed Cache/Helpers/FeedCacheTestHelpers.swift             | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift
index c462849..18ca22c 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedCacheTestHelpers.swift	
@@ -35,7 +35,9 @@ extension Date {
     private func adding(days: Int) -> Date {
         return Calendar(identifier: .gregorian).date(byAdding: .day, value: days, to: self)!
     }
-    
+}
+
+extension Date {
     func adding(seconds: TimeInterval) -> Date {
         return self + seconds
     }

From b034f0ec7b920981e0100cab71a78a8353ebfb9b Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 13:57:07 +0200
Subject: [PATCH 065/159] Retrieving from empty cache delivers empty resu:t

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 +++
 .../Feed Cache/CodableFeedStoreTests.swift    | 32 +++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 5bfbbb6..06f6c92 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -13,6 +13,7 @@
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
+		407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -49,6 +50,7 @@
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
+		407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStoreTests.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -168,6 +170,7 @@
 		40B975392D9E7AD3009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
+				407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */,
 				40B9754C2D9EC147009652B5 /* Helpers */,
 				40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */,
 				40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */,
@@ -358,6 +361,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */,
 				407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */,
 				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
new file mode 100644
index 0000000..43781e9
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -0,0 +1,32 @@
+//
+//  CodableFeedStoreTests.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
+//
+
+import XCTest
+import EssentialFeed
+
+class CodableFeedStore {
+    func retrieve(completion: @escaping FeedStore.RetrievalCompletion) {
+        completion(.empty)
+    }
+}
+
+class CodableFeedStoreTests: XCTestCase {
+    
+    func test_retrieve_deliversEmptyOnEmptyCache() {
+        let sut = CodableFeedStore()
+        let exp = expectation(description: "")
+        sut.retrieve { result in
+            exp.fulfill()
+            switch result {
+            case .empty: break
+            default: XCTFail("Expected empty result,  got \(result) instead")
+            }
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
+}

From 339d31a80c44bdb74ee15f02004f2a84bd55b674 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:00:43 +0200
Subject: [PATCH 066/159] Retrieving from empty cache twice delivers empty
 result (no side-effects)

---
 .../Feed Cache/CodableFeedStoreTests.swift       | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 43781e9..f685948 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -29,4 +29,20 @@ class CodableFeedStoreTests: XCTestCase {
         
         wait(for: [exp], timeout: 1.0)
     }
+    
+    func test_retrieve_hasNoSideEffectsOnEmptyCache() {
+        let sut = CodableFeedStore()
+        let exp = expectation(description: "Wait for cache retrieval")
+        sut.retrieve { firstResult in
+            sut.retrieve { secondResult in
+                exp.fulfill()
+                switch (firstResult, secondResult) {
+                case (.empty, .empty): break
+                default: XCTFail("Expected retrieving twice from empty cache to deliver empty result, got \(firstResult) and \(secondResult) instead")
+                }
+            }
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
 }

From cc4e793dabbc159197a9b959499db294645c37f7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:26:17 +0200
Subject: [PATCH 067/159] Retieving after inserting to empty cache delivers
 inserted values

---
 .../Feed Cache/LocalFeedImage.swift           |  2 +-
 .../Feed Cache/CodableFeedStoreTests.swift    | 48 ++++++++++++++++++-
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift
index b94cfe9..ccd72c3 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift	
@@ -8,7 +8,7 @@
 
 import Foundation
 
-public struct LocalFeedImage: Equatable {
+public struct LocalFeedImage: Equatable, Codable {
     
     public let id: UUID
     public let description: String?
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index f685948..34ed964 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -9,12 +9,38 @@ import XCTest
 import EssentialFeed
 
 class CodableFeedStore {
+    private struct Cache: Codable {
+        let feed: [LocalFeedImage]
+        let timestamp: Date
+    }
+    
+    private let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+    
     func retrieve(completion: @escaping FeedStore.RetrievalCompletion) {
-        completion(.empty)
+        guard let data = try? Data(contentsOf: storeURL) else {
+           return completion(.empty)
+        }
+        
+        let decoder = JSONDecoder()
+        let cache = try! decoder.decode(Cache.self, from: data)
+        completion(.found(feed: cache.feed, timestamp: cache.timestamp))
+    }
+    
+    func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping FeedStore.InsertionCompletion) {
+        let encoder = JSONEncoder()
+        let encoded = try! encoder.encode(Cache(feed: feed, timestamp: timestamp))
+        try! encoded.write(to: storeURL)
+        completion(nil)
     }
 }
 
 class CodableFeedStoreTests: XCTestCase {
+   
+    override func setUp() {
+        super.setUp()
+        let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+        try? FileManager.default.removeItem(at: storeURL)
+    }
     
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = CodableFeedStore()
@@ -45,4 +71,24 @@ class CodableFeedStoreTests: XCTestCase {
         
         wait(for: [exp], timeout: 1.0)
     }
+    
+    func test_retrieveAfterInsertingToEmptyCache_deliversInsertedValues() {
+        let sut = CodableFeedStore()
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        let exp = expectation(description: "Wait for cache retrieval")
+        sut.insert(feed, timestamp: timestamp) { insertionError in
+            XCTAssertNil(insertionError)
+            sut.retrieve { retrieveResult in
+                exp.fulfill()
+                switch retrieveResult {
+                case let .found(retrievedFeed, retrievedTimestamp):
+                    XCTAssertEqual(retrievedFeed, feed)
+                    XCTAssertEqual(retrievedTimestamp, timestamp)
+                default: XCTFail("Expected retrieving from cache to deliver inserted values, got \(retrieveResult) instead")
+                }
+            }
+        }
+        wait(for: [exp], timeout: 1.0)
+    }
 }

From a8bae424170b4d89d1a91af417c51cc1f1415ca7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:34:23 +0200
Subject: [PATCH 068/159] Move Codable conformance from the framework agnostic
 LocalFeedImage type to the new framework specific CodableFeedImageType (a
 private type withing the framework implementation since the Codable
 requirement is a framework specific detail)

---
 .../Feed Cache/LocalFeedImage.swift           |  2 +-
 .../Feed Cache/CodableFeedStoreTests.swift    | 32 +++++++++++++++++--
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift
index ccd72c3..b94cfe9 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedImage.swift	
@@ -8,7 +8,7 @@
 
 import Foundation
 
-public struct LocalFeedImage: Equatable, Codable {
+public struct LocalFeedImage: Equatable {
     
     public let id: UUID
     public let description: String?
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 34ed964..bbcd8fd 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -10,8 +10,33 @@ import EssentialFeed
 
 class CodableFeedStore {
     private struct Cache: Codable {
-        let feed: [LocalFeedImage]
+        let feed: [CodableFeedImage]
         let timestamp: Date
+        
+        var localFeed: [LocalFeedImage] {
+            feed.map {
+                LocalFeedImage(
+                    id: $0.id,
+                    description: $0.description,
+                    location: $0.location,
+                    url: $0.url
+                )
+            }
+        }
+    }
+    
+    private struct CodableFeedImage: Codable {
+        fileprivate let id: UUID
+        fileprivate let description: String?
+        fileprivate let location: String?
+        fileprivate let url: URL
+        
+        init(_ image: LocalFeedImage) {
+            id = image.id
+            description = image.description
+            location = image.location
+            url = image.url
+        }
     }
     
     private let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
@@ -23,12 +48,13 @@ class CodableFeedStore {
         
         let decoder = JSONDecoder()
         let cache = try! decoder.decode(Cache.self, from: data)
-        completion(.found(feed: cache.feed, timestamp: cache.timestamp))
+        completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
     }
     
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping FeedStore.InsertionCompletion) {
         let encoder = JSONEncoder()
-        let encoded = try! encoder.encode(Cache(feed: feed, timestamp: timestamp))
+        let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
+        let encoded = try! encoder.encode(cache)
         try! encoded.write(to: storeURL)
         completion(nil)
     }

From bb31318217d1fd920e07914190d054e5052d7173 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:35:24 +0200
Subject: [PATCH 069/159] Extract system under testt (sut) creation into a
 factory method

---
 .../Feed Cache/CodableFeedStoreTests.swift            | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index bbcd8fd..5aa8323 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -69,7 +69,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     func test_retrieve_deliversEmptyOnEmptyCache() {
-        let sut = CodableFeedStore()
+        let sut = makeSUT()
         let exp = expectation(description: "")
         sut.retrieve { result in
             exp.fulfill()
@@ -83,7 +83,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     func test_retrieve_hasNoSideEffectsOnEmptyCache() {
-        let sut = CodableFeedStore()
+        let sut = makeSUT()
         let exp = expectation(description: "Wait for cache retrieval")
         sut.retrieve { firstResult in
             sut.retrieve { secondResult in
@@ -99,7 +99,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     func test_retrieveAfterInsertingToEmptyCache_deliversInsertedValues() {
-        let sut = CodableFeedStore()
+        let sut = makeSUT()
         let feed = uniqueImageFeed().local
         let timestamp = Date()
         let exp = expectation(description: "Wait for cache retrieval")
@@ -117,4 +117,9 @@ class CodableFeedStoreTests: XCTestCase {
         }
         wait(for: [exp], timeout: 1.0)
     }
+    
+    // MARK: - Helpers
+    func makeSUT() -> CodableFeedStore {
+        CodableFeedStore()
+    }
 }

From 25a471eedb53f73f2e1dda3618a2519afb6d3865 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:36:10 +0200
Subject: [PATCH 070/159] Add memory leak tracking

---
 .../Feed Cache/CodableFeedStoreTests.swift               | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 5aa8323..d8f0da8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -119,7 +119,12 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     // MARK: - Helpers
-    func makeSUT() -> CodableFeedStore {
-        CodableFeedStore()
+    func makeSUT(
+        file: StaticString = #file,
+        line: UInt = #line
+    ) -> CodableFeedStore {
+        let sut = CodableFeedStore()
+        trackForMemoryLeaks(sut, file: file, line: line)
+        return sut
     }
 }

From d253d4865447988841b211bf858954eefd9cbf08 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:38:23 +0200
Subject: [PATCH 071/159] Extract hard-coded store URL from the
 CodableFeedStore production type making it an explicit dependecny (passad in
 by the tests)

---
 .../Feed Cache/CodableFeedStoreTests.swift               | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index d8f0da8..8153cbb 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -39,7 +39,11 @@ class CodableFeedStore {
         }
     }
     
-    private let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+    private let storeURL: URL
+    
+    init(storeURL: URL) {
+        self.storeURL = storeURL
+    }
     
     func retrieve(completion: @escaping FeedStore.RetrievalCompletion) {
         guard let data = try? Data(contentsOf: storeURL) else {
@@ -123,7 +127,8 @@ class CodableFeedStoreTests: XCTestCase {
         file: StaticString = #file,
         line: UInt = #line
     ) -> CodableFeedStore {
-        let sut = CodableFeedStore()
+        let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+        let sut = CodableFeedStore(storeURL: storeURL)
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }

From b6a022e8a8efcfeb8bc4af497c1bd34328e64fd8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:40:55 +0200
Subject: [PATCH 072/159] Add teardown store cleaning as an extra security
 layer (besides setUp) to ensure no artifacts are left on disk

---
 .../Feed Cache/CodableFeedStoreTests.swift                  | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 8153cbb..1eb3c66 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -72,6 +72,12 @@ class CodableFeedStoreTests: XCTestCase {
         try? FileManager.default.removeItem(at: storeURL)
     }
     
+    override func tearDown() {
+        super.setUp()
+        let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+        try? FileManager.default.removeItem(at: storeURL)
+    }
+    
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = makeSUT()
         let exp = expectation(description: "")

From a6da4d51922e8af9c152ee3b94cbb2f94e1db49b Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:42:53 +0200
Subject: [PATCH 073/159] Extract duplicated store URL creation into a helper
 factory method

---
 .../Feed Cache/CodableFeedStoreTests.swift          | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 1eb3c66..519b855 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -68,13 +68,13 @@ class CodableFeedStoreTests: XCTestCase {
    
     override func setUp() {
         super.setUp()
-        let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+        let storeURL = storeURL()
         try? FileManager.default.removeItem(at: storeURL)
     }
     
     override func tearDown() {
         super.setUp()
-        let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+        let storeURL = storeURL()
         try? FileManager.default.removeItem(at: storeURL)
     }
     
@@ -129,13 +129,16 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     // MARK: - Helpers
-    func makeSUT(
+    private func makeSUT(
         file: StaticString = #file,
         line: UInt = #line
     ) -> CodableFeedStore {
-        let storeURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
-        let sut = CodableFeedStore(storeURL: storeURL)
+        let sut = CodableFeedStore(storeURL: storeURL())
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }
+    
+    private func storeURL() -> URL {
+        FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+    }
 }

From e64aa09b4e8a924ba3327ef2927b1bd451cbefa7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:44:55 +0200
Subject: [PATCH 074/159] Replace production storeURL with a test specific
 storeURL to avoid sharing state or artifacts with other parts of the system
 (includiing other tests)

---
 .../Feed Cache/CodableFeedStoreTests.swift             | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 519b855..2fb619b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -68,13 +68,13 @@ class CodableFeedStoreTests: XCTestCase {
    
     override func setUp() {
         super.setUp()
-        let storeURL = storeURL()
+        let storeURL = testSpecificStoreURL()
         try? FileManager.default.removeItem(at: storeURL)
     }
     
     override func tearDown() {
         super.setUp()
-        let storeURL = storeURL()
+        let storeURL = testSpecificStoreURL()
         try? FileManager.default.removeItem(at: storeURL)
     }
     
@@ -133,12 +133,12 @@ class CodableFeedStoreTests: XCTestCase {
         file: StaticString = #file,
         line: UInt = #line
     ) -> CodableFeedStore {
-        let sut = CodableFeedStore(storeURL: storeURL())
+        let sut = CodableFeedStore(storeURL: testSpecificStoreURL())
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }
     
-    private func storeURL() -> URL {
-        FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image-feed.store")
+    private func testSpecificStoreURL() -> URL {
+        FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.appendingPathComponent("\(type(of: self)).store")
     }
 }

From 48d46bd4de34aad85831e50e6c65163b922abdb9 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 14:51:27 +0200
Subject: [PATCH 075/159] Add helper method to provide documentation context
 and clarify test setup and tearDown intent regarding side-effects

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 20 ++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 2fb619b..1bfa3aa 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -68,16 +68,14 @@ class CodableFeedStoreTests: XCTestCase {
    
     override func setUp() {
         super.setUp()
-        let storeURL = testSpecificStoreURL()
-        try? FileManager.default.removeItem(at: storeURL)
+        setupEmptyStoreState()
     }
     
     override func tearDown() {
         super.setUp()
-        let storeURL = testSpecificStoreURL()
-        try? FileManager.default.removeItem(at: storeURL)
+        undoStoreSideEfects()
     }
-    
+
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = makeSUT()
         let exp = expectation(description: "")
@@ -141,4 +139,16 @@ class CodableFeedStoreTests: XCTestCase {
     private func testSpecificStoreURL() -> URL {
         FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.appendingPathComponent("\(type(of: self)).store")
     }
+    
+    private func setupEmptyStoreState() {
+        deleteStoreArtifacts()
+    }
+    
+    private func undoStoreSideEfects() {
+        deleteStoreArtifacts()
+    }
+    
+    private func  deleteStoreArtifacts() {
+        try? FileManager.default.removeItem(at: testSpecificStoreURL())
+    }
 }

From ba6b07813e48d3cc466e0c1f57f05aa728a609ce Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:03:30 +0200
Subject: [PATCH 076/159] Retrieving from non empty cache twice delivers same
 found result (no side-effects)

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 1bfa3aa..fdc2245 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -126,6 +126,32 @@ class CodableFeedStoreTests: XCTestCase {
         wait(for: [exp], timeout: 1.0)
     }
     
+    func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {
+        let sut = makeSUT()
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        let exp = expectation(description: "Wait for cache insertion and double retrieval")
+        sut.insert(feed, timestamp: timestamp) { insertionError in
+            XCTAssertNil(insertionError)
+            sut.retrieve { firstResult in
+                sut.retrieve { secondResult in
+                    exp.fulfill()
+                    switch (firstResult, secondResult) {
+                    case let (.found(firstFeed, firstTimestamp), .found(secondFeed, secondTimestamp)):
+                        XCTAssertEqual(firstFeed, feed)
+                        XCTAssertEqual(firstTimestamp, timestamp)
+                        
+                        XCTAssertEqual(secondFeed, feed)
+                        XCTAssertEqual(secondTimestamp, timestamp)
+                    default: XCTFail("Expected retrieving twice from non empty cache to deliver same found result with feed \(feed) and timestamp \(timestamp), got \(firstResult) and \(secondResult) instead")
+                    }
+                }
+            }
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         file: StaticString = #file,

From 13f5f3e230b4767d43a35ed0ad82e75ba984f532 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:06:42 +0200
Subject: [PATCH 077/159] Add missing description for expectation

---
 .../EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index fdc2245..8856c42 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -78,7 +78,7 @@ class CodableFeedStoreTests: XCTestCase {
 
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = makeSUT()
-        let exp = expectation(description: "")
+        let exp = expectation(description: "Wait for cache retrieval")
         sut.retrieve { result in
             exp.fulfill()
             switch result {

From ac44e114973e2e95b1b7bcc560d7a217a021ae11 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:14:06 +0200
Subject: [PATCH 078/159] Extract the duplicated retrieve test code into a
 reusable helper method

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 47 +++++++++++--------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 8856c42..2a24556 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -78,16 +78,7 @@ class CodableFeedStoreTests: XCTestCase {
 
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = makeSUT()
-        let exp = expectation(description: "Wait for cache retrieval")
-        sut.retrieve { result in
-            exp.fulfill()
-            switch result {
-            case .empty: break
-            default: XCTFail("Expected empty result,  got \(result) instead")
-            }
-        }
-        
-        wait(for: [exp], timeout: 1.0)
+        expect(sut, toRetrieve: .empty)
     }
     
     func test_retrieve_hasNoSideEffectsOnEmptyCache() {
@@ -110,26 +101,22 @@ class CodableFeedStoreTests: XCTestCase {
         let sut = makeSUT()
         let feed = uniqueImageFeed().local
         let timestamp = Date()
+        
         let exp = expectation(description: "Wait for cache retrieval")
         sut.insert(feed, timestamp: timestamp) { insertionError in
             XCTAssertNil(insertionError)
-            sut.retrieve { retrieveResult in
-                exp.fulfill()
-                switch retrieveResult {
-                case let .found(retrievedFeed, retrievedTimestamp):
-                    XCTAssertEqual(retrievedFeed, feed)
-                    XCTAssertEqual(retrievedTimestamp, timestamp)
-                default: XCTFail("Expected retrieving from cache to deliver inserted values, got \(retrieveResult) instead")
-                }
-            }
+            exp.fulfill()
         }
         wait(for: [exp], timeout: 1.0)
+        
+        expect(sut, toRetrieve: .found(feed: feed, timestamp: timestamp))
     }
     
     func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {
         let sut = makeSUT()
         let feed = uniqueImageFeed().local
         let timestamp = Date()
+        
         let exp = expectation(description: "Wait for cache insertion and double retrieval")
         sut.insert(feed, timestamp: timestamp) { insertionError in
             XCTAssertNil(insertionError)
@@ -162,6 +149,28 @@ class CodableFeedStoreTests: XCTestCase {
         return sut
     }
     
+    private func expect(
+        _ sut: CodableFeedStore,
+        toRetrieve expectedResult: RetrieveCachedFeedResult,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let exp = expectation(description: "Wait for cache retrieval")
+        
+        sut.retrieve { retrievedResult in
+            exp.fulfill()
+            switch (expectedResult, retrievedResult) {
+            case (.empty, .empty): break
+            case let (.found(expectedFeed, expectedTimestmap), .found(retrievedFeed, retrievedTimestamp)):
+                XCTAssertEqual(expectedFeed, retrievedFeed, file: file, line: line)
+                XCTAssertEqual(expectedTimestmap, retrievedTimestamp, file: file, line: line)
+            default:
+                XCTFail("Expected to retrieve \(expectedResult), but got \(retrievedResult)", file: file, line: line)
+            }
+        }
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     private func testSpecificStoreURL() -> URL {
         FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.appendingPathComponent("\(type(of: self)).store")
     }

From 2b0cf2622f4f8b6f0a424876b2160018cff37943 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:19:00 +0200
Subject: [PATCH 079/159] Extract duplicated non-side effects-on-retrieve test
 code into a reusable helper method

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 41 +++++++------------
 1 file changed, 14 insertions(+), 27 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 2a24556..beef31f 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -83,18 +83,7 @@ class CodableFeedStoreTests: XCTestCase {
     
     func test_retrieve_hasNoSideEffectsOnEmptyCache() {
         let sut = makeSUT()
-        let exp = expectation(description: "Wait for cache retrieval")
-        sut.retrieve { firstResult in
-            sut.retrieve { secondResult in
-                exp.fulfill()
-                switch (firstResult, secondResult) {
-                case (.empty, .empty): break
-                default: XCTFail("Expected retrieving twice from empty cache to deliver empty result, got \(firstResult) and \(secondResult) instead")
-                }
-            }
-        }
-        
-        wait(for: [exp], timeout: 1.0)
+        expect(sut, toRetrieveTwice: .empty)
     }
     
     func test_retrieveAfterInsertingToEmptyCache_deliversInsertedValues() {
@@ -117,26 +106,14 @@ class CodableFeedStoreTests: XCTestCase {
         let feed = uniqueImageFeed().local
         let timestamp = Date()
         
-        let exp = expectation(description: "Wait for cache insertion and double retrieval")
+        let exp = expectation(description: "Wait for cache insertion")
         sut.insert(feed, timestamp: timestamp) { insertionError in
             XCTAssertNil(insertionError)
-            sut.retrieve { firstResult in
-                sut.retrieve { secondResult in
-                    exp.fulfill()
-                    switch (firstResult, secondResult) {
-                    case let (.found(firstFeed, firstTimestamp), .found(secondFeed, secondTimestamp)):
-                        XCTAssertEqual(firstFeed, feed)
-                        XCTAssertEqual(firstTimestamp, timestamp)
-                        
-                        XCTAssertEqual(secondFeed, feed)
-                        XCTAssertEqual(secondTimestamp, timestamp)
-                    default: XCTFail("Expected retrieving twice from non empty cache to deliver same found result with feed \(feed) and timestamp \(timestamp), got \(firstResult) and \(secondResult) instead")
-                    }
-                }
-            }
+            exp.fulfill()
         }
         
         wait(for: [exp], timeout: 1.0)
+        expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
     }
     
     // MARK: - Helpers
@@ -171,6 +148,16 @@ class CodableFeedStoreTests: XCTestCase {
         wait(for: [exp], timeout: 1.0)
     }
     
+    private func expect(
+        _ sut: CodableFeedStore,
+        toRetrieveTwice expectedResult: RetrieveCachedFeedResult,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        expect(sut, toRetrieve: expectedResult, file: file, line: line)
+        expect(sut, toRetrieve: expectedResult, file: file, line: line)
+    }
+    
     private func testSpecificStoreURL() -> URL {
         FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.appendingPathComponent("\(type(of: self)).store")
     }

From 26ee57e4f1a7cb2c5f1582e8024f1b5ddb619632 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:23:29 +0200
Subject: [PATCH 080/159] Extract duplicate insert test code into a reusable
 helper method

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 26 +++++++++----------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index beef31f..7c97242 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -91,13 +91,7 @@ class CodableFeedStoreTests: XCTestCase {
         let feed = uniqueImageFeed().local
         let timestamp = Date()
         
-        let exp = expectation(description: "Wait for cache retrieval")
-        sut.insert(feed, timestamp: timestamp) { insertionError in
-            XCTAssertNil(insertionError)
-            exp.fulfill()
-        }
-        wait(for: [exp], timeout: 1.0)
-        
+        insert((feed, timestamp), to: sut)
         expect(sut, toRetrieve: .found(feed: feed, timestamp: timestamp))
     }
     
@@ -106,13 +100,7 @@ class CodableFeedStoreTests: XCTestCase {
         let feed = uniqueImageFeed().local
         let timestamp = Date()
         
-        let exp = expectation(description: "Wait for cache insertion")
-        sut.insert(feed, timestamp: timestamp) { insertionError in
-            XCTAssertNil(insertionError)
-            exp.fulfill()
-        }
-        
-        wait(for: [exp], timeout: 1.0)
+        insert((feed, timestamp), to: sut)
         expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
     }
     
@@ -126,6 +114,16 @@ class CodableFeedStoreTests: XCTestCase {
         return sut
     }
     
+    private func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: CodableFeedStore) {
+        let exp = expectation(description: "Wait for cache insertion")
+        sut.insert(cache.feed, timestamp: cache.timestamp) { insertionError in
+            XCTAssertNil(insertionError)
+            exp.fulfill()
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     private func expect(
         _ sut: CodableFeedStore,
         toRetrieve expectedResult: RetrieveCachedFeedResult,

From 138ea634f639cf48a2b776b8b7c74beed5dac9fb Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:25:04 +0200
Subject: [PATCH 081/159] Improve test name to follow convention

---
 .../EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 7c97242..93eb576 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -86,7 +86,7 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieveTwice: .empty)
     }
     
-    func test_retrieveAfterInsertingToEmptyCache_deliversInsertedValues() {
+    func test_retrieve_deliversFoundValuesOnNonEmptyCache() {
         let sut = makeSUT()
         let feed = uniqueImageFeed().local
         let timestamp = Date()

From 3649db808ca428c7dece56adc3981437c909fcc5 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:28:10 +0200
Subject: [PATCH 082/159] Retrieve delivers error on retrieval error (invalid
 cached data in this case)

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 26 ++++++++++++++-----
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 93eb576..7945f23 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -47,12 +47,16 @@ class CodableFeedStore {
     
     func retrieve(completion: @escaping FeedStore.RetrievalCompletion) {
         guard let data = try? Data(contentsOf: storeURL) else {
-           return completion(.empty)
+            return completion(.empty)
         }
         
-        let decoder = JSONDecoder()
-        let cache = try! decoder.decode(Cache.self, from: data)
-        completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
+        do {
+            let decoder = JSONDecoder()
+            let cache = try decoder.decode(Cache.self, from: data)
+            completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
+        } catch {
+            completion(.failure(error))
+        }
     }
     
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping FeedStore.InsertionCompletion) {
@@ -65,7 +69,7 @@ class CodableFeedStore {
 }
 
 class CodableFeedStoreTests: XCTestCase {
-   
+    
     override func setUp() {
         super.setUp()
         setupEmptyStoreState()
@@ -75,7 +79,7 @@ class CodableFeedStoreTests: XCTestCase {
         super.setUp()
         undoStoreSideEfects()
     }
-
+    
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = makeSUT()
         expect(sut, toRetrieve: .empty)
@@ -104,6 +108,13 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
     }
     
+    func test_retrieve_deliversFailureOnRetrievalError() {
+        let sut = makeSUT()
+        try! "invalid data".write(to: testSpecificStoreURL(), atomically: false, encoding: .utf8)
+        
+        expect(sut, toRetrieve: .failure(anyNSError()))
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         file: StaticString = #file,
@@ -135,7 +146,8 @@ class CodableFeedStoreTests: XCTestCase {
         sut.retrieve { retrievedResult in
             exp.fulfill()
             switch (expectedResult, retrievedResult) {
-            case (.empty, .empty): break
+            case (.empty, .empty), (.failure, .failure):
+                break
             case let (.found(expectedFeed, expectedTimestmap), .found(retrievedFeed, retrievedTimestamp)):
                 XCTAssertEqual(expectedFeed, retrievedFeed, file: file, line: line)
                 XCTAssertEqual(expectedTimestmap, retrievedTimestamp, file: file, line: line)

From af91572c9dfc8fee0aa7040666ae8e898cd309bf Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:31:10 +0200
Subject: [PATCH 083/159] Make the storeURL explicit within the test to
 facilitate debugging if this test ever fails (all relevant details within a
 test method should be clearly visible)

---
 .../Feed Cache/CodableFeedStoreTests.swift               | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 7945f23..2feb3e6 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -109,18 +109,21 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     func test_retrieve_deliversFailureOnRetrievalError() {
-        let sut = makeSUT()
-        try! "invalid data".write(to: testSpecificStoreURL(), atomically: false, encoding: .utf8)
+        let storeURL = testSpecificStoreURL()
+        let sut = makeSUT(storeURL: storeURL)
+        
+        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
         
         expect(sut, toRetrieve: .failure(anyNSError()))
     }
     
     // MARK: - Helpers
     private func makeSUT(
+        storeURL: URL? = nil,
         file: StaticString = #file,
         line: UInt = #line
     ) -> CodableFeedStore {
-        let sut = CodableFeedStore(storeURL: testSpecificStoreURL())
+        let sut = CodableFeedStore(storeURL: storeURL ?? testSpecificStoreURL())
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }

From ca4121de2440aa3be7716c1110045580e128c64f Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:32:49 +0200
Subject: [PATCH 084/159] Retrieving from invalid cache twice delivers same
 error (no side-effects)

---
 .../Feed Cache/CodableFeedStoreTests.swift               | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 2feb3e6..0b61bae 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -117,6 +117,15 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieve: .failure(anyNSError()))
     }
     
+    func test_retrieve_hasNoSideEffectsOnFailure() {
+        let storeURL = testSpecificStoreURL()
+        let sut = makeSUT(storeURL: storeURL)
+        
+        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
+        
+        expect(sut, toRetrieveTwice: .failure(anyNSError()))
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,

From 352a683b080f22e36ca4915dcfcde0d82aa31ba8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:38:17 +0200
Subject: [PATCH 085/159] Inserting to a non-empty cache overrides the
 previously inserted cache value

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 23 ++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 0b61bae..e415711 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -126,6 +126,20 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieveTwice: .failure(anyNSError()))
     }
     
+    func test_insert_overridesPreviouslyInsertedCacheValues() {
+        let sut = makeSUT()
+        
+        let firstInsertionError = insert((uniqueImageFeed().local, Date()), to: sut)
+        XCTAssertNil(firstInsertionError, "Expected to insert cache succesfully")
+        
+        let latestFeed = uniqueImageFeed().local
+        let latesTimestamp = Date()
+        let latestInsertionError = insert((latestFeed, latesTimestamp), to: sut)
+        
+        XCTAssertNil(latestInsertionError, "Expected to override cache succesfully")
+        expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,
@@ -137,14 +151,17 @@ class CodableFeedStoreTests: XCTestCase {
         return sut
     }
     
-    private func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: CodableFeedStore) {
+    @discardableResult
+    private func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: CodableFeedStore) -> Error? {
         let exp = expectation(description: "Wait for cache insertion")
-        sut.insert(cache.feed, timestamp: cache.timestamp) { insertionError in
-            XCTAssertNil(insertionError)
+        var insertionError: Error?
+        sut.insert(cache.feed, timestamp: cache.timestamp) { error in
+            insertionError = error
             exp.fulfill()
         }
         
         wait(for: [exp], timeout: 1.0)
+        return insertionError
     }
     
     private func expect(

From 6ea1cd62dab3bcd86fbe31355c0f94a03e10a7c3 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:41:05 +0200
Subject: [PATCH 086/159] Insert delivers error on insertion error (invalid
 store url)

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index e415711..566fe97 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -60,11 +60,15 @@ class CodableFeedStore {
     }
     
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping FeedStore.InsertionCompletion) {
-        let encoder = JSONEncoder()
-        let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
-        let encoded = try! encoder.encode(cache)
-        try! encoded.write(to: storeURL)
-        completion(nil)
+        do {
+            let encoder = JSONEncoder()
+            let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
+            let encoded = try encoder.encode(cache)
+            try encoded.write(to: storeURL)
+            completion(nil)
+        } catch {
+            completion(error)
+        }
     }
 }
 
@@ -140,6 +144,15 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
     }
     
+    func test_insert_deliversErrorOnInsertionError() {
+        let invalidStoreURL = URL(string: "invalid://store-url")
+        let sut = makeSUT(storeURL: invalidStoreURL)
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        let insertionError = insert((feed, timestamp), to: sut)
+        XCTAssertNotNil(insertionError, "Expected cache insertion to fail ith an error")
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,

From 1d71c0168b2cab17a87a3377a860359ad5df62d0 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:44:49 +0200
Subject: [PATCH 087/159] Delete comand has no side effects on empty cache

---
 .../Feed Cache/CodableFeedStoreTests.swift        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 566fe97..fc7cd5f 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -70,6 +70,10 @@ class CodableFeedStore {
             completion(error)
         }
     }
+    
+    func deleteCachedFeed(completion: @escaping FeedStore.DeletionCompletion) {
+        completion(nil)
+    }
 }
 
 class CodableFeedStoreTests: XCTestCase {
@@ -153,6 +157,17 @@ class CodableFeedStoreTests: XCTestCase {
         XCTAssertNotNil(insertionError, "Expected cache insertion to fail ith an error")
     }
     
+    func test_delete_hasNoSideEffectsOnEmptyCache() {
+        let sut = makeSUT()
+        let exp = expectation(description: "Wait for cache deletion")
+        sut.deleteCachedFeed { _ in
+            exp.fulfill()
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+        expect(sut, toRetrieve: .empty)
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,

From 84e18d3c72207c29173d1138f93e1410ca63b446 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 15:48:46 +0200
Subject: [PATCH 088/159] Delete command empties previously inserted cache

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index fc7cd5f..2a3e40b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -72,7 +72,12 @@ class CodableFeedStore {
     }
     
     func deleteCachedFeed(completion: @escaping FeedStore.DeletionCompletion) {
-        completion(nil)
+        do {
+            try FileManager.default.removeItem(at: storeURL)
+            completion(nil)
+        } catch {
+            completion(error)
+        }
     }
 }
 
@@ -168,6 +173,19 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieve: .empty)
     }
     
+    func test_delete_emptiesPreviouslyInsertedCache() {
+        let sut = makeSUT()
+        insert((uniqueImageFeed().local, Date()), to: sut)
+        
+        let exp = expectation(description: "Wait for cache deletion")
+        sut.deleteCachedFeed { _ in
+            exp.fulfill()
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+        expect(sut, toRetrieve: .empty)
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,

From 48bdcc6e00ad00f0f471e536ff2b5932a82174b5 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:04:49 +0200
Subject: [PATCH 089/159] Delete command delviers error on deletion error

---
 .../Feed Cache/CodableFeedStoreTests.swift           | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 2a3e40b..cc69e28 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -186,6 +186,18 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieve: .empty)
     }
     
+    func test_delete_deliversErrorOnDeletionError() {
+        let noDeletePermissionURL = FileManager.default.urls(for: .cachesDirectory, in: .systemDomainMask).first
+        let sut = makeSUT(storeURL: noDeletePermissionURL)
+        let exp = expectation(description: "Wait for deletion")
+        sut.deleteCachedFeed {
+            exp.fulfill()
+            XCTAssertNotNil($0)
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,

From 04c308f31957759473ecd4d442fa5cbe2082d495 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:13:44 +0200
Subject: [PATCH 090/159] Abstract delete cache test logic into a shared
 reusable helper

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 42 ++++++++++---------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index cc69e28..bf26546 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -72,6 +72,10 @@ class CodableFeedStore {
     }
     
     func deleteCachedFeed(completion: @escaping FeedStore.DeletionCompletion) {
+        guard FileManager.default.fileExists(atPath: storeURL.path) else {
+            return completion(nil)
+        }
+        
         do {
             try FileManager.default.removeItem(at: storeURL)
             completion(nil)
@@ -164,38 +168,25 @@ class CodableFeedStoreTests: XCTestCase {
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {
         let sut = makeSUT()
-        let exp = expectation(description: "Wait for cache deletion")
-        sut.deleteCachedFeed { _ in
-            exp.fulfill()
-        }
+        let deletionError = deleteCache(from: sut)
         
-        wait(for: [exp], timeout: 1.0)
+        XCTAssertNil(deletionError, "Expected empty cache deletion to succeed")
         expect(sut, toRetrieve: .empty)
     }
     
     func test_delete_emptiesPreviouslyInsertedCache() {
         let sut = makeSUT()
         insert((uniqueImageFeed().local, Date()), to: sut)
-        
-        let exp = expectation(description: "Wait for cache deletion")
-        sut.deleteCachedFeed { _ in
-            exp.fulfill()
-        }
-        
-        wait(for: [exp], timeout: 1.0)
+        let deletionError = deleteCache(from: sut)
+        XCTAssertNil(deletionError, "Expected non-empty cache deletion to succeed")
         expect(sut, toRetrieve: .empty)
     }
     
     func test_delete_deliversErrorOnDeletionError() {
         let noDeletePermissionURL = FileManager.default.urls(for: .cachesDirectory, in: .systemDomainMask).first
         let sut = makeSUT(storeURL: noDeletePermissionURL)
-        let exp = expectation(description: "Wait for deletion")
-        sut.deleteCachedFeed {
-            exp.fulfill()
-            XCTAssertNotNil($0)
-        }
-        
-        wait(for: [exp], timeout: 1.0)
+        let deletionError = deleteCache(from: sut)
+        XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
     }
     
     // MARK: - Helpers
@@ -222,6 +213,19 @@ class CodableFeedStoreTests: XCTestCase {
         return insertionError
     }
     
+    @discardableResult
+    private func deleteCache(from sut: CodableFeedStore) -> Error? {
+        let exp = expectation(description: "Wait for cache deletion")
+        var receivedError: Error?
+        sut.deleteCachedFeed {
+            exp.fulfill()
+            receivedError = $0
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+        return receivedError
+    }
+    
     private func expect(
         _ sut: CodableFeedStore,
         toRetrieve expectedResult: RetrieveCachedFeedResult,

From 6d36c8fe224f6df390a307123d334fd28d510b03 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:16:05 +0200
Subject: [PATCH 091/159] Move system mask caches directory instantiation into
 a factory method to make code more self documented

---
 .../Feed Cache/CodableFeedStoreTests.swift                  | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index bf26546..03f554f 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -183,7 +183,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     func test_delete_deliversErrorOnDeletionError() {
-        let noDeletePermissionURL = FileManager.default.urls(for: .cachesDirectory, in: .systemDomainMask).first
+        let noDeletePermissionURL = systemMaskCachesDirectory()
         let sut = makeSUT(storeURL: noDeletePermissionURL)
         let deletionError = deleteCache(from: sut)
         XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
@@ -259,6 +259,10 @@ class CodableFeedStoreTests: XCTestCase {
         expect(sut, toRetrieve: expectedResult, file: file, line: line)
     }
     
+    private func systemMaskCachesDirectory() -> URL {
+        FileManager.default.urls(for: .cachesDirectory, in: .systemDomainMask).first!
+    }
+    
     private func testSpecificStoreURL() -> URL {
         FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.appendingPathComponent("\(type(of: self)).store")
     }

From d85553c85e4449af76b4440401cdbda53fae692c Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:17:43 +0200
Subject: [PATCH 092/159] Add spacing in tests to reflect Given-When-Then
 structure

---
 .../EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 03f554f..260ad85 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -177,7 +177,9 @@ class CodableFeedStoreTests: XCTestCase {
     func test_delete_emptiesPreviouslyInsertedCache() {
         let sut = makeSUT()
         insert((uniqueImageFeed().local, Date()), to: sut)
+        
         let deletionError = deleteCache(from: sut)
+        
         XCTAssertNil(deletionError, "Expected non-empty cache deletion to succeed")
         expect(sut, toRetrieve: .empty)
     }
@@ -185,7 +187,9 @@ class CodableFeedStoreTests: XCTestCase {
     func test_delete_deliversErrorOnDeletionError() {
         let noDeletePermissionURL = systemMaskCachesDirectory()
         let sut = makeSUT(storeURL: noDeletePermissionURL)
+        
         let deletionError = deleteCache(from: sut)
+        
         XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
     }
     

From d8a581e36a9851742db2d0bfeeab5d7d12f301be Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:19:14 +0200
Subject: [PATCH 093/159] Make the CodableFeedStore conform to FeedStore

---
 .../Feed Cache/CodableFeedStoreTests.swift                | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 260ad85..eeb36d8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -8,7 +8,7 @@
 import XCTest
 import EssentialFeed
 
-class CodableFeedStore {
+class CodableFeedStore: FeedStore {
     private struct Cache: Codable {
         let feed: [CodableFeedImage]
         let timestamp: Date
@@ -45,7 +45,7 @@ class CodableFeedStore {
         self.storeURL = storeURL
     }
     
-    func retrieve(completion: @escaping FeedStore.RetrievalCompletion) {
+    func retrieve(completion: @escaping RetrievalCompletion) {
         guard let data = try? Data(contentsOf: storeURL) else {
             return completion(.empty)
         }
@@ -59,7 +59,7 @@ class CodableFeedStore {
         }
     }
     
-    func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping FeedStore.InsertionCompletion) {
+    func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
         do {
             let encoder = JSONEncoder()
             let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
@@ -71,7 +71,7 @@ class CodableFeedStore {
         }
     }
     
-    func deleteCachedFeed(completion: @escaping FeedStore.DeletionCompletion) {
+    func deleteCachedFeed(completion: @escaping DeletionCompletion) {
         guard FileManager.default.fileExists(atPath: storeURL.path) else {
             return completion(nil)
         }

From bd54559621abbbbed5229dce844ab15d63ef9593 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:22:29 +0200
Subject: [PATCH 094/159] Replace concrete CodableFeedStore dependency in test
 with the FeedStore protocol to make the tests more docupled from the concrete
 production implementation (also proving we respect the Liskov Sustitution
 Principle)

---
 .../Feed Cache/CodableFeedStoreTests.swift             | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index eeb36d8..5ac62f8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -198,14 +198,14 @@ class CodableFeedStoreTests: XCTestCase {
         storeURL: URL? = nil,
         file: StaticString = #file,
         line: UInt = #line
-    ) -> CodableFeedStore {
+    ) -> FeedStore {
         let sut = CodableFeedStore(storeURL: storeURL ?? testSpecificStoreURL())
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }
     
     @discardableResult
-    private func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: CodableFeedStore) -> Error? {
+    private func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: FeedStore) -> Error? {
         let exp = expectation(description: "Wait for cache insertion")
         var insertionError: Error?
         sut.insert(cache.feed, timestamp: cache.timestamp) { error in
@@ -218,7 +218,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     @discardableResult
-    private func deleteCache(from sut: CodableFeedStore) -> Error? {
+    private func deleteCache(from sut: FeedStore) -> Error? {
         let exp = expectation(description: "Wait for cache deletion")
         var receivedError: Error?
         sut.deleteCachedFeed {
@@ -231,7 +231,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     private func expect(
-        _ sut: CodableFeedStore,
+        _ sut: FeedStore,
         toRetrieve expectedResult: RetrieveCachedFeedResult,
         file: StaticString = #file,
         line: UInt = #line
@@ -254,7 +254,7 @@ class CodableFeedStoreTests: XCTestCase {
     }
     
     private func expect(
-        _ sut: CodableFeedStore,
+        _ sut: FeedStore,
         toRetrieveTwice expectedResult: RetrieveCachedFeedResult,
         file: StaticString = #file,
         line: UInt = #line

From 1df730c4122ef0db7af6fc06084c95466e6bbece Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Fri, 4 Apr 2025 16:24:44 +0200
Subject: [PATCH 095/159] Move CodableFeedStore to its own file in production

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 +
 .../Feed Cache/CodableFeedStore.swift         | 86 +++++++++++++++++++
 .../Feed Cache/CodableFeedStoreTests.swift    | 77 +----------------
 3 files changed, 91 insertions(+), 76 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 06f6c92..a7f353a 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -14,6 +14,7 @@
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
 		407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */; };
+		407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FB02DA022C00070F56E /* CodableFeedStore.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -51,6 +52,7 @@
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
 		407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStoreTests.swift; sourceTree = "<group>"; };
+		407F4FB02DA022C00070F56E /* CodableFeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStore.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -186,6 +188,7 @@
 				407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
 				40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */,
+				407F4FB02DA022C00070F56E /* CodableFeedStore.swift */,
 			);
 			path = "Feed Cache";
 			sourceTree = "<group>";
@@ -353,6 +356,7 @@
 				40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */,
 				407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
+				407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift
new file mode 100644
index 0000000..ca0a30d
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift	
@@ -0,0 +1,86 @@
+//
+//  CodableFeedStore.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
+//
+
+
+import Foundation
+
+public class CodableFeedStore: FeedStore {
+    private struct Cache: Codable {
+        let feed: [CodableFeedImage]
+        let timestamp: Date
+        
+        var localFeed: [LocalFeedImage] {
+            feed.map {
+                LocalFeedImage(
+                    id: $0.id,
+                    description: $0.description,
+                    location: $0.location,
+                    url: $0.url
+                )
+            }
+        }
+    }
+    
+    private struct CodableFeedImage: Codable {
+        fileprivate let id: UUID
+        fileprivate let description: String?
+        fileprivate let location: String?
+        fileprivate let url: URL
+        
+        init(_ image: LocalFeedImage) {
+            id = image.id
+            description = image.description
+            location = image.location
+            url = image.url
+        }
+    }
+    
+    private let storeURL: URL
+    
+    public init(storeURL: URL) {
+        self.storeURL = storeURL
+    }
+    
+    public func retrieve(completion: @escaping RetrievalCompletion) {
+        guard let data = try? Data(contentsOf: storeURL) else {
+            return completion(.empty)
+        }
+        
+        do {
+            let decoder = JSONDecoder()
+            let cache = try decoder.decode(Cache.self, from: data)
+            completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
+        } catch {
+            completion(.failure(error))
+        }
+    }
+    
+    public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+        do {
+            let encoder = JSONEncoder()
+            let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
+            let encoded = try encoder.encode(cache)
+            try encoded.write(to: storeURL)
+            completion(nil)
+        } catch {
+            completion(error)
+        }
+    }
+    
+    public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+        guard FileManager.default.fileExists(atPath: storeURL.path) else {
+            return completion(nil)
+        }
+        
+        do {
+            try FileManager.default.removeItem(at: storeURL)
+            completion(nil)
+        } catch {
+            completion(error)
+        }
+    }
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 5ac62f8..2aac366 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -8,82 +8,7 @@
 import XCTest
 import EssentialFeed
 
-class CodableFeedStore: FeedStore {
-    private struct Cache: Codable {
-        let feed: [CodableFeedImage]
-        let timestamp: Date
-        
-        var localFeed: [LocalFeedImage] {
-            feed.map {
-                LocalFeedImage(
-                    id: $0.id,
-                    description: $0.description,
-                    location: $0.location,
-                    url: $0.url
-                )
-            }
-        }
-    }
-    
-    private struct CodableFeedImage: Codable {
-        fileprivate let id: UUID
-        fileprivate let description: String?
-        fileprivate let location: String?
-        fileprivate let url: URL
-        
-        init(_ image: LocalFeedImage) {
-            id = image.id
-            description = image.description
-            location = image.location
-            url = image.url
-        }
-    }
-    
-    private let storeURL: URL
-    
-    init(storeURL: URL) {
-        self.storeURL = storeURL
-    }
-    
-    func retrieve(completion: @escaping RetrievalCompletion) {
-        guard let data = try? Data(contentsOf: storeURL) else {
-            return completion(.empty)
-        }
-        
-        do {
-            let decoder = JSONDecoder()
-            let cache = try decoder.decode(Cache.self, from: data)
-            completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
-        } catch {
-            completion(.failure(error))
-        }
-    }
-    
-    func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-        do {
-            let encoder = JSONEncoder()
-            let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
-            let encoded = try encoder.encode(cache)
-            try encoded.write(to: storeURL)
-            completion(nil)
-        } catch {
-            completion(error)
-        }
-    }
-    
-    func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        guard FileManager.default.fileExists(atPath: storeURL.path) else {
-            return completion(nil)
-        }
-        
-        do {
-            try FileManager.default.removeItem(at: storeURL)
-            completion(nil)
-        } catch {
-            completion(error)
-        }
-    }
-}
+
 
 class CodableFeedStoreTests: XCTestCase {
     

From 6edb1ca7f52d126ae9653ff17f7e4b01d6886abe Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:23:12 +0200
Subject: [PATCH 096/159] Proved that the `CodableFeedStore` side-effects run
 serially

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 2aac366..da4ecf2 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -118,6 +118,33 @@ class CodableFeedStoreTests: XCTestCase {
         XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
     }
     
+    func test_storeSideEffects_runSerially() {
+        let sut = makeSUT()
+        var completedOperationsInOrder = [XCTestExpectation]()
+        
+        let op1 = expectation(description: "Operation 1")
+        sut.insert(uniqueImageFeed().local, timestamp: Date()) { _ in
+            completedOperationsInOrder.append(op1)
+            op1.fulfill()
+        }
+        
+        let op2 = expectation(description: "Operation 2")
+        sut.deleteCachedFeed { _ in
+            completedOperationsInOrder.append(op2)
+            op2.fulfill()
+        }
+        
+        let op3 = expectation(description: "Operation 3")
+        sut.insert(uniqueImageFeed().local, timestamp: Date()) { _ in
+            completedOperationsInOrder.append(op3)
+            op3.fulfill()
+        }
+        
+        waitForExpectations(timeout: 5.0)
+        
+        XCTAssertEqual(completedOperationsInOrder, [op1,op2,op3], "Expected operations to run serially but operations finished in the wrong order")
+    }
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,

From f09d5a18536f19828545569d0a3a70ba377a95c7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:33:33 +0200
Subject: [PATCH 097/159] Dispatch the `CodableFeedStore` operations in a
 serial background queue to avoid blocking clients

---
 .../Feed Cache/CodableFeedStore.swift         | 64 +++++++++++--------
 1 file changed, 37 insertions(+), 27 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift
index ca0a30d..b5a3fcf 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift	
@@ -40,47 +40,57 @@ public class CodableFeedStore: FeedStore {
     }
     
     private let storeURL: URL
+    private let queue = DispatchQueue(
+        label: "\(CodableFeedStore.self)-queue",
+        qos: .userInitiated
+    )
     
     public init(storeURL: URL) {
         self.storeURL = storeURL
     }
     
     public func retrieve(completion: @escaping RetrievalCompletion) {
-        guard let data = try? Data(contentsOf: storeURL) else {
-            return completion(.empty)
-        }
-        
-        do {
-            let decoder = JSONDecoder()
-            let cache = try decoder.decode(Cache.self, from: data)
-            completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
-        } catch {
-            completion(.failure(error))
+        queue.async { [storeURL] in
+            guard let data = try? Data(contentsOf: storeURL) else {
+                return completion(.empty)
+            }
+            
+            do {
+                let decoder = JSONDecoder()
+                let cache = try decoder.decode(Cache.self, from: data)
+                completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
+            } catch {
+                completion(.failure(error))
+            }
         }
     }
     
     public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-        do {
-            let encoder = JSONEncoder()
-            let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
-            let encoded = try encoder.encode(cache)
-            try encoded.write(to: storeURL)
-            completion(nil)
-        } catch {
-            completion(error)
+        queue.async { [storeURL] in
+            do {
+                let encoder = JSONEncoder()
+                let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
+                let encoded = try encoder.encode(cache)
+                try encoded.write(to: storeURL)
+                completion(nil)
+            } catch {
+                completion(error)
+            }
         }
     }
     
     public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        guard FileManager.default.fileExists(atPath: storeURL.path) else {
-            return completion(nil)
-        }
-        
-        do {
-            try FileManager.default.removeItem(at: storeURL)
-            completion(nil)
-        } catch {
-            completion(error)
+        queue.async { [storeURL] in
+            guard FileManager.default.fileExists(atPath: storeURL.path) else {
+                return completion(nil)
+            }
+            
+            do {
+                try FileManager.default.removeItem(at: storeURL)
+                completion(nil)
+            } catch {
+                completion(error)
+            }
         }
     }
 }

From 278dd4b196e7ec547a63789fd68d6ca60a67eca3 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:37:51 +0200
Subject: [PATCH 098/159] Make the `CodableFeedStore` queue concurrent to allow
 multiple `retrieve` to be processed in parallel (since it has no side-effecs)
 and use `barriers` when performing side-effects to guarantee data consistency
 and avoid race conditions

---
 .../EssentialFeed/Feed Cache/CodableFeedStore.swift        | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift
index b5a3fcf..d939603 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift	
@@ -42,7 +42,8 @@ public class CodableFeedStore: FeedStore {
     private let storeURL: URL
     private let queue = DispatchQueue(
         label: "\(CodableFeedStore.self)-queue",
-        qos: .userInitiated
+        qos: .userInitiated,
+        attributes: .concurrent
     )
     
     public init(storeURL: URL) {
@@ -66,7 +67,7 @@ public class CodableFeedStore: FeedStore {
     }
     
     public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-        queue.async { [storeURL] in
+        queue.async(flags: .barrier) { [storeURL] in
             do {
                 let encoder = JSONEncoder()
                 let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
@@ -80,7 +81,7 @@ public class CodableFeedStore: FeedStore {
     }
     
     public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        queue.async { [storeURL] in
+        queue.async(flags: .barrier) { [storeURL] in
             guard FileManager.default.fileExists(atPath: storeURL.path) else {
                 return completion(nil)
             }

From f08fc5a7b141faabf85fa65436bf57d0f1dfe424 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:41:00 +0200
Subject: [PATCH 099/159] Add comments to document that completion handlers in
 any `FeedStore` implementation can be invoked in any thread. Clients are
 responsbile to dispatch to appropiate threads, if needed

---
 EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 8810996..26b34a8 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -18,8 +18,16 @@ public protocol FeedStore {
     typealias InsertionCompletion = (Error?) -> Void
     typealias RetrievalCompletion = (RetrieveCachedFeedResult) -> Void
     
+    /// The completion handler can be invoked in any thread.
+    /// Clients are responsible to dispatch to appropiate threads, if needed.
     func deleteCachedFeed(completion: @escaping DeletionCompletion)
+    
+    /// The completion handler can be invoked in any thread.
+    /// Clients are responsible to dispatch to appropiate threads, if needed.
     func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion)
+    
+    /// The completion handler can be invoked in any thread.
+    /// Clients are responsible to dispatch to appropiate threads, if needed.
     func retrieve(completion: @escaping RetrievalCompletion)
 }
 

From 2238e1a2100131f2c228ffcd2358a970470bfee0 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:42:08 +0200
Subject: [PATCH 100/159] Add comment to document that the completion handler
 in any `HTTPClient` implementation can be invoked in any thread. Clients are
 responsible to dispatch to appropiate threads, if needed.

---
 EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift b/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift
index dc7f988..aa292c8 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift
@@ -12,5 +12,8 @@ public enum HTTPClientResult {
 }
 
 public protocol HTTPClient {
+    
+    /// The completion handler can be invoked in any thread.
+    /// Clients are responsible to dispatch to appropiate threads, if needed.
     func get(from url: URL, completion: @escaping (HTTPClientResult) -> Void)
 }

From 15a0438a146ad38ac6fbfa55bff1e5d15b730606 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:53:40 +0200
Subject: [PATCH 101/159] Break down `CodableFeedStore`tests to guarantee
 there's only one assertion per test. The goal is clarify the behavior under
 test in small units, so we can extract the behaviour tests into reusable
 specs.

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 47 ++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index da4ecf2..e458fd8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -8,7 +8,34 @@
 import XCTest
 import EssentialFeed
 
+protocol FeedStoreSpecs {
+    func test_retrieve_deliversEmptyOnEmptyCache()
+    func test_retrieve_hasNoSideEffectsOnEmptyCache()
+    func test_retrieve_deliversFoundValuesOnNonEmptyCache()
+    func test_retrieve_hasNoSideEffectsOnNonEmptyCache()
+    
+    func test_insert_overridesPreviouslyInsertedCacheValues()
+    
+    func test_delete_hasNoSideEffectsOnEmptyCache()
+    func test_delete_emptiesPreviouslyInsertedCache()
+    
+    func test_storeSideEffects_runSerially()
+}
+
+protocol FailableRetrieveFeedStoreSpecs {
+    func test_retrieve_deliversFailureOnRetrievalError()
+    func test_retrieve_hasNoSideEffectsOnFailure()
+}
 
+protocol FailableInsertFeedStoreSpecs {
+    func test_insert_deliversErrorOnInsertionError()
+    func test_insert_hasNoSideEffectsOnInsertionError()
+}
+
+protocol FailableDeleteFeedStoreSpecs {
+    func test_delete_deliversErrorOnDeletionError()
+    func test_delete_hasNoSideEffectsOnDeletionError()
+}
 
 class CodableFeedStoreTests: XCTestCase {
     
@@ -88,7 +115,17 @@ class CodableFeedStoreTests: XCTestCase {
         let feed = uniqueImageFeed().local
         let timestamp = Date()
         let insertionError = insert((feed, timestamp), to: sut)
-        XCTAssertNotNil(insertionError, "Expected cache insertion to fail ith an error")
+        XCTAssertNotNil(insertionError, "Expected cache insertion to fail with an error")
+    }
+    
+    func test_insert_hasNoSideEffectsOnInsertionError() {
+        let invalidStoreURL = URL(string: "invalid://store-url")
+        let sut = makeSUT(storeURL: invalidStoreURL)
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        
+        insert((feed, timestamp), to: sut)
+        expect(sut, toRetrieve: .empty)
     }
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {
@@ -118,6 +155,14 @@ class CodableFeedStoreTests: XCTestCase {
         XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
     }
     
+    func test_delete_hasNoSideEffectsOnDeletionError() {
+        let noDeletePermissionURL = systemMaskCachesDirectory()
+        let sut = makeSUT(storeURL: noDeletePermissionURL)
+        
+        deleteCache(from: sut)
+        expect(sut, toRetrieve: .empty)
+    }
+    
     func test_storeSideEffects_runSerially() {
         let sut = makeSUT()
         var completedOperationsInOrder = [XCTestExpectation]()

From 4ab67376303aac73a3063c1b3366caaeb216d988 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:56:36 +0200
Subject: [PATCH 102/159] Create `FeedStoreSpecs`that must be implemented by
 any `FeedStore`test implementation to guarantee it meets spec.

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 ++
 .../Feed Cache/CodableFeedStoreTests.swift    | 31 +---------------
 .../Feed Cache/FeedStoreSpecs.swift           | 37 +++++++++++++++++++
 3 files changed, 42 insertions(+), 30 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index a7f353a..e27d48a 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -15,6 +15,7 @@
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
 		407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */; };
 		407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FB02DA022C00070F56E /* CodableFeedStore.swift */; };
+		407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -53,6 +54,7 @@
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
 		407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStoreTests.swift; sourceTree = "<group>"; };
 		407F4FB02DA022C00070F56E /* CodableFeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStore.swift; sourceTree = "<group>"; };
+		407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpecs.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -173,6 +175,7 @@
 			isa = PBXGroup;
 			children = (
 				407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */,
+				407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */,
 				40B9754C2D9EC147009652B5 /* Helpers */,
 				40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */,
 				40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */,
@@ -370,6 +373,7 @@
 				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
 				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
+				407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */,
 				407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index e458fd8..c032b4c 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -8,36 +8,7 @@
 import XCTest
 import EssentialFeed
 
-protocol FeedStoreSpecs {
-    func test_retrieve_deliversEmptyOnEmptyCache()
-    func test_retrieve_hasNoSideEffectsOnEmptyCache()
-    func test_retrieve_deliversFoundValuesOnNonEmptyCache()
-    func test_retrieve_hasNoSideEffectsOnNonEmptyCache()
-    
-    func test_insert_overridesPreviouslyInsertedCacheValues()
-    
-    func test_delete_hasNoSideEffectsOnEmptyCache()
-    func test_delete_emptiesPreviouslyInsertedCache()
-    
-    func test_storeSideEffects_runSerially()
-}
-
-protocol FailableRetrieveFeedStoreSpecs {
-    func test_retrieve_deliversFailureOnRetrievalError()
-    func test_retrieve_hasNoSideEffectsOnFailure()
-}
-
-protocol FailableInsertFeedStoreSpecs {
-    func test_insert_deliversErrorOnInsertionError()
-    func test_insert_hasNoSideEffectsOnInsertionError()
-}
-
-protocol FailableDeleteFeedStoreSpecs {
-    func test_delete_deliversErrorOnDeletionError()
-    func test_delete_hasNoSideEffectsOnDeletionError()
-}
-
-class CodableFeedStoreTests: XCTestCase {
+class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
     
     override func setUp() {
         super.setUp()
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift
new file mode 100644
index 0000000..57d2192
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
@@ -0,0 +1,37 @@
+//
+//  FeedStoreSpecs.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 7/4/25.
+//
+
+protocol FeedStoreSpecs {
+    func test_retrieve_deliversEmptyOnEmptyCache()
+    func test_retrieve_hasNoSideEffectsOnEmptyCache()
+    func test_retrieve_deliversFoundValuesOnNonEmptyCache()
+    func test_retrieve_hasNoSideEffectsOnNonEmptyCache()
+    
+    func test_insert_overridesPreviouslyInsertedCacheValues()
+    
+    func test_delete_hasNoSideEffectsOnEmptyCache()
+    func test_delete_emptiesPreviouslyInsertedCache()
+    
+    func test_storeSideEffects_runSerially()
+}
+
+protocol FailableRetrieveFeedStoreSpecs: FeedStoreSpecs {
+    func test_retrieve_deliversFailureOnRetrievalError()
+    func test_retrieve_hasNoSideEffectsOnFailure()
+}
+
+protocol FailableInsertFeedStoreSpecs: FeedStoreSpecs {
+    func test_insert_deliversErrorOnInsertionError()
+    func test_insert_hasNoSideEffectsOnInsertionError()
+}
+
+protocol FailableDeleteFeedStoreSpecs: FeedStoreSpecs {
+    func test_delete_deliversErrorOnDeletionError()
+    func test_delete_hasNoSideEffectsOnDeletionError()
+}
+
+typealias FailableFeedStoreSpecs = FailableRetrieveFeedStoreSpecs & FailableInsertFeedStoreSpecs & FailableDeleteFeedStoreSpecs

From 3ae4780009c871c9489362abc634092ee1f7e377 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Mon, 7 Apr 2025 14:59:38 +0200
Subject: [PATCH 103/159] Extract reusable `FeedStoreSpecs`helper methods into
 a shared scope so it can be used by any other `FeedStore` implementation
 tests

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 ++
 .../Feed Cache/CodableFeedStoreTests.swift    | 59 ----------------
 .../XCTestCase+FeedStoreSpecs.swift           | 69 +++++++++++++++++++
 3 files changed, 73 insertions(+), 59 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index e27d48a..fbad37f 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -16,6 +16,7 @@
 		407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */; };
 		407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FB02DA022C00070F56E /* CodableFeedStore.swift */; };
 		407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */; };
+		407F4FCC2DA403330070F56E /* XCTestCase+FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -55,6 +56,7 @@
 		407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStoreTests.swift; sourceTree = "<group>"; };
 		407F4FB02DA022C00070F56E /* CodableFeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStore.swift; sourceTree = "<group>"; };
 		407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpecs.swift; sourceTree = "<group>"; };
+		407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "XCTestCase+FeedStoreSpecs.swift"; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -175,6 +177,7 @@
 			isa = PBXGroup;
 			children = (
 				407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */,
+				407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */,
 				407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */,
 				40B9754C2D9EC147009652B5 /* Helpers */,
 				40B9754A2D9EC05C009652B5 /* LoadFeedFromCacheUseCaseTests.swift */,
@@ -375,6 +378,7 @@
 				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
 				407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */,
 				407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */,
+				407F4FCC2DA403330070F56E /* XCTestCase+FeedStoreSpecs.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index c032b4c..35ae017 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -172,65 +172,6 @@ class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
         return sut
     }
     
-    @discardableResult
-    private func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: FeedStore) -> Error? {
-        let exp = expectation(description: "Wait for cache insertion")
-        var insertionError: Error?
-        sut.insert(cache.feed, timestamp: cache.timestamp) { error in
-            insertionError = error
-            exp.fulfill()
-        }
-        
-        wait(for: [exp], timeout: 1.0)
-        return insertionError
-    }
-    
-    @discardableResult
-    private func deleteCache(from sut: FeedStore) -> Error? {
-        let exp = expectation(description: "Wait for cache deletion")
-        var receivedError: Error?
-        sut.deleteCachedFeed {
-            exp.fulfill()
-            receivedError = $0
-        }
-        
-        wait(for: [exp], timeout: 1.0)
-        return receivedError
-    }
-    
-    private func expect(
-        _ sut: FeedStore,
-        toRetrieve expectedResult: RetrieveCachedFeedResult,
-        file: StaticString = #file,
-        line: UInt = #line
-    ) {
-        let exp = expectation(description: "Wait for cache retrieval")
-        
-        sut.retrieve { retrievedResult in
-            exp.fulfill()
-            switch (expectedResult, retrievedResult) {
-            case (.empty, .empty), (.failure, .failure):
-                break
-            case let (.found(expectedFeed, expectedTimestmap), .found(retrievedFeed, retrievedTimestamp)):
-                XCTAssertEqual(expectedFeed, retrievedFeed, file: file, line: line)
-                XCTAssertEqual(expectedTimestmap, retrievedTimestamp, file: file, line: line)
-            default:
-                XCTFail("Expected to retrieve \(expectedResult), but got \(retrievedResult)", file: file, line: line)
-            }
-        }
-        wait(for: [exp], timeout: 1.0)
-    }
-    
-    private func expect(
-        _ sut: FeedStore,
-        toRetrieveTwice expectedResult: RetrieveCachedFeedResult,
-        file: StaticString = #file,
-        line: UInt = #line
-    ) {
-        expect(sut, toRetrieve: expectedResult, file: file, line: line)
-        expect(sut, toRetrieve: expectedResult, file: file, line: line)
-    }
-    
     private func systemMaskCachesDirectory() -> URL {
         FileManager.default.urls(for: .cachesDirectory, in: .systemDomainMask).first!
     }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
new file mode 100644
index 0000000..8eb802b
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -0,0 +1,69 @@
+//
+//  XCTestCase+FeedStoreSpecs.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 7/4/25.
+//
+import XCTest
+import EssentialFeed
+
+extension FeedStoreSpecs where Self: XCTestCase {
+    @discardableResult
+    func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: FeedStore) -> Error? {
+        let exp = expectation(description: "Wait for cache insertion")
+        var insertionError: Error?
+        sut.insert(cache.feed, timestamp: cache.timestamp) { error in
+            insertionError = error
+            exp.fulfill()
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+        return insertionError
+    }
+    
+    @discardableResult
+    func deleteCache(from sut: FeedStore) -> Error? {
+        let exp = expectation(description: "Wait for cache deletion")
+        var receivedError: Error?
+        sut.deleteCachedFeed {
+            exp.fulfill()
+            receivedError = $0
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+        return receivedError
+    }
+    
+    func expect(
+        _ sut: FeedStore,
+        toRetrieve expectedResult: RetrieveCachedFeedResult,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let exp = expectation(description: "Wait for cache retrieval")
+        
+        sut.retrieve { retrievedResult in
+            exp.fulfill()
+            switch (expectedResult, retrievedResult) {
+            case (.empty, .empty), (.failure, .failure):
+                break
+            case let (.found(expectedFeed, expectedTimestmap), .found(retrievedFeed, retrievedTimestamp)):
+                XCTAssertEqual(expectedFeed, retrievedFeed, file: file, line: line)
+                XCTAssertEqual(expectedTimestmap, retrievedTimestamp, file: file, line: line)
+            default:
+                XCTFail("Expected to retrieve \(expectedResult), but got \(retrievedResult)", file: file, line: line)
+            }
+        }
+        wait(for: [exp], timeout: 1.0)
+    }
+    
+    func expect(
+        _ sut: FeedStore,
+        toRetrieveTwice expectedResult: RetrieveCachedFeedResult,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        expect(sut, toRetrieve: expectedResult, file: file, line: line)
+        expect(sut, toRetrieve: expectedResult, file: file, line: line)
+    }
+}

From 1f29743fe0a25488e8271efbc68d7a208f2aed0b Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Tue, 8 Apr 2025 10:27:00 +0200
Subject: [PATCH 104/159] Move failable protocol methods to their own extension
 to have a better view of which method belongs to which protocol

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 117 ++++++++++--------
 .../Feed Cache/FeedStoreSpecs.swift           |   2 -
 2 files changed, 62 insertions(+), 57 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 35ae017..0d88ec9 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -8,7 +8,7 @@
 import XCTest
 import EssentialFeed
 
-class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
+class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
     
     override func setUp() {
         super.setUp()
@@ -48,24 +48,6 @@ class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
         expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
     }
     
-    func test_retrieve_deliversFailureOnRetrievalError() {
-        let storeURL = testSpecificStoreURL()
-        let sut = makeSUT(storeURL: storeURL)
-        
-        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
-        
-        expect(sut, toRetrieve: .failure(anyNSError()))
-    }
-    
-    func test_retrieve_hasNoSideEffectsOnFailure() {
-        let storeURL = testSpecificStoreURL()
-        let sut = makeSUT(storeURL: storeURL)
-        
-        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
-        
-        expect(sut, toRetrieveTwice: .failure(anyNSError()))
-    }
-    
     func test_insert_overridesPreviouslyInsertedCacheValues() {
         let sut = makeSUT()
         
@@ -80,25 +62,6 @@ class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
         expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
     }
     
-    func test_insert_deliversErrorOnInsertionError() {
-        let invalidStoreURL = URL(string: "invalid://store-url")
-        let sut = makeSUT(storeURL: invalidStoreURL)
-        let feed = uniqueImageFeed().local
-        let timestamp = Date()
-        let insertionError = insert((feed, timestamp), to: sut)
-        XCTAssertNotNil(insertionError, "Expected cache insertion to fail with an error")
-    }
-    
-    func test_insert_hasNoSideEffectsOnInsertionError() {
-        let invalidStoreURL = URL(string: "invalid://store-url")
-        let sut = makeSUT(storeURL: invalidStoreURL)
-        let feed = uniqueImageFeed().local
-        let timestamp = Date()
-        
-        insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieve: .empty)
-    }
-    
     func test_delete_hasNoSideEffectsOnEmptyCache() {
         let sut = makeSUT()
         let deletionError = deleteCache(from: sut)
@@ -117,23 +80,6 @@ class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
         expect(sut, toRetrieve: .empty)
     }
     
-    func test_delete_deliversErrorOnDeletionError() {
-        let noDeletePermissionURL = systemMaskCachesDirectory()
-        let sut = makeSUT(storeURL: noDeletePermissionURL)
-        
-        let deletionError = deleteCache(from: sut)
-        
-        XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
-    }
-    
-    func test_delete_hasNoSideEffectsOnDeletionError() {
-        let noDeletePermissionURL = systemMaskCachesDirectory()
-        let sut = makeSUT(storeURL: noDeletePermissionURL)
-        
-        deleteCache(from: sut)
-        expect(sut, toRetrieve: .empty)
-    }
-    
     func test_storeSideEffects_runSerially() {
         let sut = makeSUT()
         var completedOperationsInOrder = [XCTestExpectation]()
@@ -192,3 +138,64 @@ class CodableFeedStoreTests: XCTestCase, FailableFeedStoreSpecs {
         try? FileManager.default.removeItem(at: testSpecificStoreURL())
     }
 }
+
+extension CodableFeedStoreTests: FailableRetrieveFeedStoreSpecs {
+    func test_retrieve_deliversFailureOnRetrievalError() {
+        let storeURL = testSpecificStoreURL()
+        let sut = makeSUT(storeURL: storeURL)
+        
+        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
+        
+        expect(sut, toRetrieve: .failure(anyNSError()))
+    }
+    
+    func test_retrieve_hasNoSideEffectsOnFailure() {
+        let storeURL = testSpecificStoreURL()
+        let sut = makeSUT(storeURL: storeURL)
+        
+        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
+        
+        expect(sut, toRetrieveTwice: .failure(anyNSError()))
+    }
+}
+
+extension CodableFeedStoreTests: FailableInsertFeedStoreSpecs {
+    func test_insert_deliversErrorOnInsertionError() {
+        let invalidStoreURL = URL(string: "invalid://store-url")
+        let sut = makeSUT(storeURL: invalidStoreURL)
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        let insertionError = insert((feed, timestamp), to: sut)
+        XCTAssertNotNil(insertionError, "Expected cache insertion to fail with an error")
+    }
+    
+    func test_insert_hasNoSideEffectsOnInsertionError() {
+        let invalidStoreURL = URL(string: "invalid://store-url")
+        let sut = makeSUT(storeURL: invalidStoreURL)
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        
+        insert((feed, timestamp), to: sut)
+        expect(sut, toRetrieve: .empty)
+    }
+}
+
+
+extension CodableFeedStoreTests: FailableDeleteFeedStoreSpecs {
+    func test_delete_deliversErrorOnDeletionError() {
+        let noDeletePermissionURL = systemMaskCachesDirectory()
+        let sut = makeSUT(storeURL: noDeletePermissionURL)
+        
+        let deletionError = deleteCache(from: sut)
+        
+        XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
+    }
+    
+    func test_delete_hasNoSideEffectsOnDeletionError() {
+        let noDeletePermissionURL = systemMaskCachesDirectory()
+        let sut = makeSUT(storeURL: noDeletePermissionURL)
+        
+        deleteCache(from: sut)
+        expect(sut, toRetrieve: .empty)
+    }
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift
index 57d2192..78cea96 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
@@ -33,5 +33,3 @@ protocol FailableDeleteFeedStoreSpecs: FeedStoreSpecs {
     func test_delete_deliversErrorOnDeletionError()
     func test_delete_hasNoSideEffectsOnDeletionError()
 }
-
-typealias FailableFeedStoreSpecs = FailableRetrieveFeedStoreSpecs & FailableInsertFeedStoreSpecs & FailableDeleteFeedStoreSpecs

From 2a76201b87887618480defa1fed80756a922081f Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Tue, 8 Apr 2025 10:30:11 +0200
Subject: [PATCH 105/159] Extract common specs into asserts so we can reuse
 implementation when testing differents persistency solutions (frameworks)

---
 .../Feed Cache/CodableFeedStoreTests.swift    |  62 ++--------
 .../XCTestCase+FeedStoreSpecs.swift           | 110 ++++++++++++++++++
 2 files changed, 118 insertions(+), 54 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 0d88ec9..d9188d1 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -22,89 +22,43 @@ class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
     
     func test_retrieve_deliversEmptyOnEmptyCache() {
         let sut = makeSUT()
-        expect(sut, toRetrieve: .empty)
+        assertThatStoreSideEffectsRunSerially(on: sut)
     }
     
     func test_retrieve_hasNoSideEffectsOnEmptyCache() {
         let sut = makeSUT()
-        expect(sut, toRetrieveTwice: .empty)
+        assertThatRetrieveHasNoSideEffectsOnEmptyCache(on: sut)
     }
     
     func test_retrieve_deliversFoundValuesOnNonEmptyCache() {
         let sut = makeSUT()
-        let feed = uniqueImageFeed().local
-        let timestamp = Date()
-        
-        insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieve: .found(feed: feed, timestamp: timestamp))
+        assertThatRetrieveDeliversFoundValuesOnNonEmptyCache(on: sut)
     }
     
     func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {
         let sut = makeSUT()
-        let feed = uniqueImageFeed().local
-        let timestamp = Date()
-        
-        insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
+        assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(on: sut)
     }
     
     func test_insert_overridesPreviouslyInsertedCacheValues() {
         let sut = makeSUT()
         
-        let firstInsertionError = insert((uniqueImageFeed().local, Date()), to: sut)
-        XCTAssertNil(firstInsertionError, "Expected to insert cache succesfully")
-        
-        let latestFeed = uniqueImageFeed().local
-        let latesTimestamp = Date()
-        let latestInsertionError = insert((latestFeed, latesTimestamp), to: sut)
-        
-        XCTAssertNil(latestInsertionError, "Expected to override cache succesfully")
-        expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
+        assertThatInsertOverridesPreviouslyInsertedCacheValues(on: sut)
     }
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {
         let sut = makeSUT()
-        let deletionError = deleteCache(from: sut)
-        
-        XCTAssertNil(deletionError, "Expected empty cache deletion to succeed")
-        expect(sut, toRetrieve: .empty)
+        assertThatDeleteHasNoSideEffectOnEmptyCache(on: sut)
     }
     
     func test_delete_emptiesPreviouslyInsertedCache() {
         let sut = makeSUT()
-        insert((uniqueImageFeed().local, Date()), to: sut)
-        
-        let deletionError = deleteCache(from: sut)
-        
-        XCTAssertNil(deletionError, "Expected non-empty cache deletion to succeed")
-        expect(sut, toRetrieve: .empty)
+        assertThatDeleteEmptiesPreviouslyInsertedCache(on: sut)
     }
     
     func test_storeSideEffects_runSerially() {
         let sut = makeSUT()
-        var completedOperationsInOrder = [XCTestExpectation]()
-        
-        let op1 = expectation(description: "Operation 1")
-        sut.insert(uniqueImageFeed().local, timestamp: Date()) { _ in
-            completedOperationsInOrder.append(op1)
-            op1.fulfill()
-        }
-        
-        let op2 = expectation(description: "Operation 2")
-        sut.deleteCachedFeed { _ in
-            completedOperationsInOrder.append(op2)
-            op2.fulfill()
-        }
-        
-        let op3 = expectation(description: "Operation 3")
-        sut.insert(uniqueImageFeed().local, timestamp: Date()) { _ in
-            completedOperationsInOrder.append(op3)
-            op3.fulfill()
-        }
-        
-        waitForExpectations(timeout: 5.0)
-        
-        XCTAssertEqual(completedOperationsInOrder, [op1,op2,op3], "Expected operations to run serially but operations finished in the wrong order")
+        assertThatStoreSideEffectsRunSerially(on: sut)
     }
     
     // MARK: - Helpers
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index 8eb802b..e5fa8c9 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -66,4 +66,114 @@ extension FeedStoreSpecs where Self: XCTestCase {
         expect(sut, toRetrieve: expectedResult, file: file, line: line)
         expect(sut, toRetrieve: expectedResult, file: file, line: line)
     }
+    
+    func assertThatRetrieveDeliversEmptyOnEmptyCache(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        expect(sut, toRetrieve: .empty)
+    }
+    
+    func assertThatRetrieveHasNoSideEffectsOnEmptyCache(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        expect(sut, toRetrieveTwice: .empty)
+    }
+    
+    func assertThatRetrieveDeliversFoundValuesOnNonEmptyCache(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        
+        insert((feed, timestamp), to: sut)
+        expect(sut, toRetrieve: .found(feed: feed, timestamp: timestamp))
+    }
+    
+    func assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let feed = uniqueImageFeed().local
+        let timestamp = Date()
+        
+        insert((feed, timestamp), to: sut)
+        expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
+    }
+    
+    func assertThatInsertOverridesPreviouslyInsertedCacheValues(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let firstInsertionError = insert((uniqueImageFeed().local, Date()), to: sut)
+        XCTAssertNil(firstInsertionError, "Expected to insert cache succesfully")
+        
+        let latestFeed = uniqueImageFeed().local
+        let latesTimestamp = Date()
+        let latestInsertionError = insert((latestFeed, latesTimestamp), to: sut)
+        
+        XCTAssertNil(latestInsertionError, "Expected to override cache succesfully")
+        expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
+    }
+    
+    func assertThatDeleteHasNoSideEffectOnEmptyCache(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let deletionError = deleteCache(from: sut)
+        
+        XCTAssertNil(deletionError, "Expected empty cache deletion to succeed")
+        expect(sut, toRetrieve: .empty)
+    }
+    
+    func assertThatDeleteEmptiesPreviouslyInsertedCache(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        insert((uniqueImageFeed().local, Date()), to: sut)
+        
+        let deletionError = deleteCache(from: sut)
+        
+        XCTAssertNil(deletionError, "Expected non-empty cache deletion to succeed")
+        expect(sut, toRetrieve: .empty)
+    }
+    
+    func assertThatStoreSideEffectsRunSerially(
+        on sut: FeedStore,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        var completedOperationsInOrder = [XCTestExpectation]()
+        
+        let op1 = expectation(description: "Operation 1")
+        sut.insert(uniqueImageFeed().local, timestamp: Date()) { _ in
+            completedOperationsInOrder.append(op1)
+            op1.fulfill()
+        }
+        
+        let op2 = expectation(description: "Operation 2")
+        sut.deleteCachedFeed { _ in
+            completedOperationsInOrder.append(op2)
+            op2.fulfill()
+        }
+        
+        let op3 = expectation(description: "Operation 3")
+        sut.insert(uniqueImageFeed().local, timestamp: Date()) { _ in
+            completedOperationsInOrder.append(op3)
+            op3.fulfill()
+        }
+        
+        waitForExpectations(timeout: 5.0)
+        
+        XCTAssertEqual(completedOperationsInOrder, [op1,op2,op3], "Expected operations to run serially but operations finished in the wrong order")
+    }
 }

From 8c0ac1a8101b54df96a6ae476f323c27208d7e47 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Tue, 8 Apr 2025 12:24:02 +0200
Subject: [PATCH 106/159] Add empty core data feed store specs

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 +++
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   | 34 +++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index fbad37f..ef856a5 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -17,6 +17,7 @@
 		407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FB02DA022C00070F56E /* CodableFeedStore.swift */; };
 		407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */; };
 		407F4FCC2DA403330070F56E /* XCTestCase+FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */; };
+		407F4FD12DA530810070F56E /* CoreDataFeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -57,6 +58,7 @@
 		407F4FB02DA022C00070F56E /* CodableFeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStore.swift; sourceTree = "<group>"; };
 		407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpecs.swift; sourceTree = "<group>"; };
 		407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "XCTestCase+FeedStoreSpecs.swift"; sourceTree = "<group>"; };
+		407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataFeedStoreSpecs.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -177,6 +179,7 @@
 			isa = PBXGroup;
 			children = (
 				407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */,
+				407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */,
 				407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */,
 				407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */,
 				40B9754C2D9EC147009652B5 /* Helpers */,
@@ -374,6 +377,7 @@
 				407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */,
 				407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */,
 				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
+				407F4FD12DA530810070F56E /* CoreDataFeedStoreSpecs.swift in Sources */,
 				40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */,
 				40B9754B2D9EC061009652B5 /* LoadFeedFromCacheUseCaseTests.swift in Sources */,
 				407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */,
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
new file mode 100644
index 0000000..87a66a6
--- /dev/null
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -0,0 +1,34 @@
+//
+//  CoreDataFeedStoreSpecs.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 8/4/25.
+//
+
+import XCTest
+
+class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
+    func test_retrieve_deliversEmptyOnEmptyCache() {
+    }
+    
+    func test_retrieve_hasNoSideEffectsOnEmptyCache() {
+    }
+    
+    func test_retrieve_deliversFoundValuesOnNonEmptyCache() {
+    }
+    
+    func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {
+    }
+    
+    func test_insert_overridesPreviouslyInsertedCacheValues() {
+    }
+    
+    func test_delete_hasNoSideEffectsOnEmptyCache() {
+    }
+    
+    func test_delete_emptiesPreviouslyInsertedCache() {
+    }
+    
+    func test_storeSideEffects_runSerially() {
+    }
+}

From 870e879434bc6fb617f1dfc48fce5af93edae79d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Tue, 8 Apr 2025 12:30:14 +0200
Subject: [PATCH 107/159] Retrieve command delivers empty on empty cache

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 +++
 .../Feed Cache/CoreDataStore.swift            | 26 +++++++++++++++++++
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   | 10 +++++++
 3 files changed, 40 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index ef856a5..b91a947 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -18,6 +18,7 @@
 		407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */; };
 		407F4FCC2DA403330070F56E /* XCTestCase+FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */; };
 		407F4FD12DA530810070F56E /* CoreDataFeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */; };
+		407F4FD32DA531050070F56E /* CoreDataStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD22DA530FF0070F56E /* CoreDataStore.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -59,6 +60,7 @@
 		407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpecs.swift; sourceTree = "<group>"; };
 		407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "XCTestCase+FeedStoreSpecs.swift"; sourceTree = "<group>"; };
 		407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataFeedStoreSpecs.swift; sourceTree = "<group>"; };
+		407F4FD22DA530FF0070F56E /* CoreDataStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataStore.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -193,6 +195,7 @@
 		40B975412D9E9FB7009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
+				407F4FD22DA530FF0070F56E /* CoreDataStore.swift */,
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
 				407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
@@ -366,6 +369,7 @@
 				407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */,
+				407F4FD32DA531050070F56E /* CoreDataStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
new file mode 100644
index 0000000..5530f2f
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -0,0 +1,26 @@
+//
+//  CoreDataStore.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 8/4/25.
+//
+
+import Foundation
+
+public final class CoreDataStore: FeedStore {
+    
+    public init() {}
+    
+    public func retrieve(completion: @escaping RetrievalCompletion) {
+        completion(.empty)
+    }
+
+    public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+        
+    }
+    
+    
+    public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+        
+    }
+}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 87a66a6..c874f8a 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -6,9 +6,12 @@
 //
 
 import XCTest
+import EssentialFeed
 
 class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     func test_retrieve_deliversEmptyOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatRetrieveDeliversEmptyOnEmptyCache(on: sut)
     }
     
     func test_retrieve_hasNoSideEffectsOnEmptyCache() {
@@ -31,4 +34,11 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     
     func test_storeSideEffects_runSerially() {
     }
+    
+    // MARK: - Helpers
+    private func makeSUT(file: StaticString = #file, line: UInt = #line) -> CoreDataStore {
+        let sut = CoreDataStore()
+        trackForMemoryLeaks(sut, file: file, line: line)
+        return sut
+    }
 }

From 56fa809399d6d8c753c173a175b9dccae5409193 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Tue, 8 Apr 2025 12:30:58 +0200
Subject: [PATCH 108/159] Retrieve command has no side effects on empty cache

---
 .../EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift  | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index c874f8a..6480e45 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -15,6 +15,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_retrieve_hasNoSideEffectsOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatRetrieveHasNoSideEffectsOnEmptyCache(on: sut)
     }
     
     func test_retrieve_deliversFoundValuesOnNonEmptyCache() {

From dbd48706417c6f9e0de2a43e2b657ad0a7121cbf Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 09:24:05 +0200
Subject: [PATCH 109/159] Add CoreDataFeedStoer data model

---
 .../EssentialFeed.xcodeproj/project.pbxproj     | 17 +++++++++++++++++
 .../FeedStore.xcdatamodel/contents              | 14 ++++++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index b91a947..c8d9865 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -10,6 +10,7 @@
 		080EDEFB21B6DA7E00813479 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedImage.swift */; };
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
+		40412A172DA65403004677C4 /* FeedStore.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
@@ -52,6 +53,7 @@
 		080EDF0121B6DA7E00813479 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		080EDF0B21B6DAE800813479 /* FeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedImage.swift; sourceTree = "<group>"; };
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
+		40412A162DA65403004677C4 /* FeedStore.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = FeedStore.xcdatamodel; sourceTree = "<group>"; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
@@ -196,6 +198,7 @@
 			isa = PBXGroup;
 			children = (
 				407F4FD22DA530FF0070F56E /* CoreDataStore.swift */,
+				40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */,
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
 				407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
@@ -363,6 +366,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				40412A172DA65403004677C4 /* FeedStore.xcdatamodeld in Sources */,
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
 				080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */,
 				40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */,
@@ -727,6 +731,19 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCVersionGroup section */
+		40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */ = {
+			isa = XCVersionGroup;
+			children = (
+				40412A162DA65403004677C4 /* FeedStore.xcdatamodel */,
+			);
+			currentVersion = 40412A162DA65403004677C4 /* FeedStore.xcdatamodel */;
+			path = FeedStore.xcdatamodeld;
+			sourceTree = "<group>";
+			versionGroupType = wrapper.xcdatamodel;
+		};
+/* End XCVersionGroup section */
 	};
 	rootObject = 080EDEE821B6DA7E00813479 /* Project object */;
 }
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents
new file mode 100644
index 0000000..7182245
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents	
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="23605" systemVersion="24A335" minimumToolsVersion="Automatic" sourceLanguage="Swift" userDefinedModelVersionIdentifier="">
+    <entity name="ManagedCache" representedClassName="ManagedCache" syncable="YES">
+        <attribute name="timestamp" attributeType="Date" usesScalarValueType="NO"/>
+        <relationship name="feed" toMany="YES" deletionRule="Cascade" ordered="YES" destinationEntity="ManagedFeedImage" inverseName="cache" inverseEntity="ManagedFeedImage"/>
+    </entity>
+    <entity name="ManagedFeedImage" representedClassName="ManagedFeedImage" syncable="YES">
+        <attribute name="id" attributeType="UUID" usesScalarValueType="NO"/>
+        <attribute name="imageDescription" optional="YES" attributeType="String"/>
+        <attribute name="location" optional="YES" attributeType="String"/>
+        <attribute name="url" attributeType="URI"/>
+        <relationship name="cache" maxCount="1" deletionRule="Nullify" destinationEntity="ManagedCache" inverseName="feed" inverseEntity="ManagedCache"/>
+    </entity>
+</model>
\ No newline at end of file

From d065ca97759c67e957cc51ebfd4b0d9761b57c20 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 09:26:25 +0200
Subject: [PATCH 110/159] Add `ManagedCache` and `ManagedFeedImage` model
 representations

---
 .../EssentialFeed/Feed Cache/CoreDataStore.swift  | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index 5530f2f..257ff18 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -5,7 +5,7 @@
 //  Created by Cristian Felipe Patiño Rojas on 8/4/25.
 //
 
-import Foundation
+import CoreData
 
 public final class CoreDataStore: FeedStore {
     
@@ -24,3 +24,16 @@ public final class CoreDataStore: FeedStore {
         
     }
 }
+
+private class ManagedCache: NSManagedObject {
+    @NSManaged var timestamp: Date
+    @NSManaged var feed: NSOrderedSet
+}
+
+private class ManagedFeedImage: NSManagedObject {
+    @NSManaged var id: UUID
+    @NSManaged var imageDescription: String?
+    @NSManaged var location: String?
+    @NSManaged var url: URL
+    @NSManaged var cache: ManagedCache
+}

From 345dbf7b56e3e8beb515711e195856914d9f4b4b Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 09:34:05 +0200
Subject: [PATCH 111/159] Load persistent container upon `CoreDataFeedStoer`
 initialization

---
 .../Feed Cache/CoreDataStore.swift            | 36 ++++++++++++++++++-
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   |  3 +-
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index 257ff18..93480a7 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -9,7 +9,10 @@ import CoreData
 
 public final class CoreDataStore: FeedStore {
     
-    public init() {}
+    let container: NSPersistentContainer
+    public init(bundle: Bundle = .main) throws {
+        container = try NSPersistentContainer.load(modelName: "FeedStore", in: bundle)
+    }
     
     public func retrieve(completion: @escaping RetrievalCompletion) {
         completion(.empty)
@@ -25,6 +28,37 @@ public final class CoreDataStore: FeedStore {
     }
 }
 
+private extension NSPersistentContainer {
+    enum LoadingError: Error {
+        case modelNotFound
+        case failedToPersistentStores(Error)
+    }
+    
+    static func load(modelName name: String, in bundle: Bundle) throws -> NSPersistentContainer {
+        guard let model = NSManagedObjectModel.with(name: name, in: bundle) else { throw LoadingError.modelNotFound }
+        let container = NSPersistentContainer(name: name, managedObjectModel: model)
+        var loadError: Error?
+        container.loadPersistentStores {
+            loadError = $1
+        }
+        
+        try loadError.map {
+            throw LoadingError.failedToPersistentStores($0)
+        }
+        
+        return container
+    }
+}
+
+private extension NSManagedObjectModel {
+    static func with(name: String, in bundle: Bundle) -> NSManagedObjectModel? {
+        return bundle.url(forResource: name, withExtension: "momd")
+            .flatMap {
+                NSManagedObjectModel(contentsOf: $0)
+            }
+    }
+}
+
 private class ManagedCache: NSManagedObject {
     @NSManaged var timestamp: Date
     @NSManaged var feed: NSOrderedSet
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 6480e45..14a02e5 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -39,7 +39,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     
     // MARK: - Helpers
     private func makeSUT(file: StaticString = #file, line: UInt = #line) -> CoreDataStore {
-        let sut = CoreDataStore()
+        let storeBundle = Bundle(for: CoreDataStore.self)
+        let sut = try! CoreDataStore(bundle: storeBundle)
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }

From e9ce2b0f1ad449c0f8a2e855e44931b5554405ce Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 09:35:00 +0200
Subject: [PATCH 112/159] Add private background context to perform store
 operations

---
 EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index 93480a7..e3b0891 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -10,8 +10,10 @@ import CoreData
 public final class CoreDataStore: FeedStore {
     
     let container: NSPersistentContainer
+    private let context: NSManagedObjectContext
     public init(bundle: Bundle = .main) throws {
         container = try NSPersistentContainer.load(modelName: "FeedStore", in: bundle)
+        context = container.newBackgroundContext()
     }
     
     public func retrieve(completion: @escaping RetrievalCompletion) {

From 49e62b38dca4b3d23a6ebd92dbee928819c3e4b9 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 09:38:29 +0200
Subject: [PATCH 113/159] Mke `storeURL` an explicit dependency so we can
 inject test-specific URLs (such as `/dev/null`) to avoid sharing state with
 production (and other tests!)

---
 .../Feed Cache/CoreDataStore.swift            | 19 ++++++++++++++++---
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   |  6 +++++-
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index e3b0891..ccfa252 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -11,8 +11,12 @@ public final class CoreDataStore: FeedStore {
     
     let container: NSPersistentContainer
     private let context: NSManagedObjectContext
-    public init(bundle: Bundle = .main) throws {
-        container = try NSPersistentContainer.load(modelName: "FeedStore", in: bundle)
+    public init(storeURL: URL, bundle: Bundle = .main) throws {
+        container = try NSPersistentContainer.load(
+            modelName: "FeedStore",
+            url: storeURL,
+            in: bundle
+        )
         context = container.newBackgroundContext()
     }
     
@@ -36,9 +40,18 @@ private extension NSPersistentContainer {
         case failedToPersistentStores(Error)
     }
     
-    static func load(modelName name: String, in bundle: Bundle) throws -> NSPersistentContainer {
+    static func load(
+        modelName name: String,
+        url: URL,
+        in bundle: Bundle
+    ) throws -> NSPersistentContainer {
         guard let model = NSManagedObjectModel.with(name: name, in: bundle) else { throw LoadingError.modelNotFound }
         let container = NSPersistentContainer(name: name, managedObjectModel: model)
+        
+        container.persistentStoreDescriptions = [
+            NSPersistentStoreDescription(url: url)
+        ]
+        
         var loadError: Error?
         container.loadPersistentStores {
             loadError = $1
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 14a02e5..0d057e5 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -40,7 +40,11 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     // MARK: - Helpers
     private func makeSUT(file: StaticString = #file, line: UInt = #line) -> CoreDataStore {
         let storeBundle = Bundle(for: CoreDataStore.self)
-        let sut = try! CoreDataStore(bundle: storeBundle)
+        let storeURL = URL(fileURLWithPath: "/dev/null")
+        let sut = try! CoreDataStore(
+            storeURL: storeURL,
+            bundle: storeBundle
+        )
         trackForMemoryLeaks(sut, file: file, line: line)
         return sut
     }

From c0a87d6b3f48c113c536f3c9921ea63ee8115747 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 09:59:13 +0200
Subject: [PATCH 114/159] `CoreDataFeedStore.retrieve()` delivers found values
 on non-empty cache

---
 .../Feed Cache/CoreDataStore.swift            | 48 ++++++++++++++++++-
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   |  2 +
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index ccfa252..faeaded 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -21,10 +21,54 @@ public final class CoreDataStore: FeedStore {
     }
     
     public func retrieve(completion: @escaping RetrievalCompletion) {
-        completion(.empty)
+        context.perform { [context] in
+            
+            do {
+                let request = NSFetchRequest<ManagedCache>(entityName: ManagedCache.entity().name!)
+                request.returnsObjectsAsFaults = false
+                if let cache = try context.fetch(request).first {
+                    let feed = cache.feed
+                        .compactMap { ($0 as? ManagedFeedImage) }
+                        .map {
+                            LocalFeedImage(
+                                id: $0.id,
+                                description: $0.imageDescription,
+                                location: $0.location,
+                                url: $0.url
+                            )
+                        }
+                
+                    completion(.found(feed: feed, timestamp: cache.timestamp))
+                } else {
+                    completion(.empty)
+                }
+            } catch {
+                completion(.failure(error))
+            }
+        }
     }
 
     public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+        context.perform { [context] in
+            do {
+                let managedCache = ManagedCache(context: context)
+                managedCache.timestamp = timestamp
+                let managedFeed = feed.map {
+                    let managedFeedImage = ManagedFeedImage(context: context)
+                    managedFeedImage.id = $0.id
+                    managedFeedImage.imageDescription = $0.description
+                    managedFeedImage.location = $0.location
+                    managedFeedImage.url = $0.url
+                    return managedFeedImage
+                }
+                
+                managedCache.feed = NSOrderedSet(array: managedFeed)
+                try context.save()
+                completion(nil)
+            } catch {
+                completion(error)
+            }
+        }
         
     }
     
@@ -74,11 +118,13 @@ private extension NSManagedObjectModel {
     }
 }
 
+@objc(ManagedCache)
 private class ManagedCache: NSManagedObject {
     @NSManaged var timestamp: Date
     @NSManaged var feed: NSOrderedSet
 }
 
+@objc(ManagedFeedImage)
 private class ManagedFeedImage: NSManagedObject {
     @NSManaged var id: UUID
     @NSManaged var imageDescription: String?
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 0d057e5..6aa2de4 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -20,6 +20,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_retrieve_deliversFoundValuesOnNonEmptyCache() {
+        let sut = makeSUT()
+        assertThatRetrieveDeliversFoundValuesOnNonEmptyCache(on: sut)
     }
     
     func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {

From 677ec7d353277ce4c55d75c8ed8097a4dd334ad9 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:05:42 +0200
Subject: [PATCH 115/159] Extract model translations into helper methods within
 the managed models

---
 .../Feed Cache/CoreDataStore.swift            | 52 +++++++++++--------
 1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index faeaded..ff09841 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -27,18 +27,7 @@ public final class CoreDataStore: FeedStore {
                 let request = NSFetchRequest<ManagedCache>(entityName: ManagedCache.entity().name!)
                 request.returnsObjectsAsFaults = false
                 if let cache = try context.fetch(request).first {
-                    let feed = cache.feed
-                        .compactMap { ($0 as? ManagedFeedImage) }
-                        .map {
-                            LocalFeedImage(
-                                id: $0.id,
-                                description: $0.imageDescription,
-                                location: $0.location,
-                                url: $0.url
-                            )
-                        }
-                
-                    completion(.found(feed: feed, timestamp: cache.timestamp))
+                    completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
                 } else {
                     completion(.empty)
                 }
@@ -53,16 +42,10 @@ public final class CoreDataStore: FeedStore {
             do {
                 let managedCache = ManagedCache(context: context)
                 managedCache.timestamp = timestamp
-                let managedFeed = feed.map {
-                    let managedFeedImage = ManagedFeedImage(context: context)
-                    managedFeedImage.id = $0.id
-                    managedFeedImage.imageDescription = $0.description
-                    managedFeedImage.location = $0.location
-                    managedFeedImage.url = $0.url
-                    return managedFeedImage
-                }
-                
-                managedCache.feed = NSOrderedSet(array: managedFeed)
+                managedCache.feed = ManagedFeedImage.images(
+                    from: feed,
+                    in: context
+                )
                 try context.save()
                 completion(nil)
             } catch {
@@ -122,6 +105,10 @@ private extension NSManagedObjectModel {
 private class ManagedCache: NSManagedObject {
     @NSManaged var timestamp: Date
     @NSManaged var feed: NSOrderedSet
+    
+    var localFeed: [LocalFeedImage] {
+        return feed.compactMap { ($0 as? ManagedFeedImage)?.local }
+    }
 }
 
 @objc(ManagedFeedImage)
@@ -131,4 +118,25 @@ private class ManagedFeedImage: NSManagedObject {
     @NSManaged var location: String?
     @NSManaged var url: URL
     @NSManaged var cache: ManagedCache
+    
+    static func images(from localFeed: [LocalFeedImage], in context: NSManagedObjectContext) -> NSOrderedSet {
+        let managedFeedImages = localFeed.map {
+            let managedFeedImage = ManagedFeedImage(context: context)
+            managedFeedImage.id = $0.id
+            managedFeedImage.imageDescription = $0.description
+            managedFeedImage.location = $0.location
+            managedFeedImage.url = $0.url
+            return managedFeedImage
+        }
+        return NSOrderedSet(array: managedFeedImages)
+    }
+    
+    var local: LocalFeedImage {
+        LocalFeedImage(
+            id: id,
+            description: imageDescription,
+            location: location,
+            url: url
+        )
+    }
 }

From 94a41b3c4c908900b1f3643c311d88c8cf38af6a Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:08:39 +0200
Subject: [PATCH 116/159] Extract `ManagedCache` fetch request logic into a
 helper method within the managed model class

---
 .../EssentialFeed/Feed Cache/CoreDataStore.swift       | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index ff09841..80c9e07 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -24,9 +24,7 @@ public final class CoreDataStore: FeedStore {
         context.perform { [context] in
             
             do {
-                let request = NSFetchRequest<ManagedCache>(entityName: ManagedCache.entity().name!)
-                request.returnsObjectsAsFaults = false
-                if let cache = try context.fetch(request).first {
+                if let cache = try ManagedCache.find(in: context) {
                     completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
                 } else {
                     completion(.empty)
@@ -109,6 +107,12 @@ private class ManagedCache: NSManagedObject {
     var localFeed: [LocalFeedImage] {
         return feed.compactMap { ($0 as? ManagedFeedImage)?.local }
     }
+    
+    static func find(in context: NSManagedObjectContext) throws -> ManagedCache? {
+        let request = NSFetchRequest<ManagedCache>(entityName: entity().name!)
+        request.returnsObjectsAsFaults = false
+        return try context.fetch(request).first
+    }
 }
 
 @objc(ManagedFeedImage)

From 0fa69a82c9bd1e2d05d702057c734dd2aaa36cd8 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:09:26 +0200
Subject: [PATCH 117/159] `CorerDataFeedStore.retrieve()` has no side-effects
 on non-empty cache

---
 .../EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift  | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 6aa2de4..a5bdab8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -25,6 +25,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {
+        let sut = makeSUT()
+        assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(on: sut)
     }
     
     func test_insert_overridesPreviouslyInsertedCacheValues() {

From d3a9500852f0b50f15a2f580dd5133c2bb19acbe Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:17:27 +0200
Subject: [PATCH 118/159] Add missing inert methods in spec and implement
 testing in CodableStore

---
 .../Feed Cache/CodableFeedStoreTests.swift    | 10 ++++++++
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   |  3 +++
 .../Feed Cache/FeedStoreSpecs.swift           |  2 ++
 .../XCTestCase+FeedStoreSpecs.swift           | 23 ++++++++++++++++++-
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index d9188d1..92f62d1 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -40,6 +40,16 @@ class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
         assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(on: sut)
     }
     
+    func test_insert_deliversNoErrorOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatInsertDeliversNoErrorOnEmptyCache(on: sut)
+    }
+    
+    func test_insert_deliversNoErrorOnNonEmptyCache() {
+        let sut = makeSUT()
+        assertThatInsertDeliversNoErrorOnNonEmptyCache(on: sut)
+    }
+    
     func test_insert_overridesPreviouslyInsertedCacheValues() {
         let sut = makeSUT()
         
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index a5bdab8..ce4ce74 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -29,6 +29,9 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
         assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(on: sut)
     }
     
+    func test_insert_deliversNoErrorOnEmptyCache() {}
+    func test_insert_deliversNoErrorOnNonEmptyCache() {}
+    
     func test_insert_overridesPreviouslyInsertedCacheValues() {
     }
     
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift
index 78cea96..f3ca41b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
@@ -11,6 +11,8 @@ protocol FeedStoreSpecs {
     func test_retrieve_deliversFoundValuesOnNonEmptyCache()
     func test_retrieve_hasNoSideEffectsOnNonEmptyCache()
     
+    func test_insert_deliversNoErrorOnEmptyCache()
+    func test_insert_deliversNoErrorOnNonEmptyCache()
     func test_insert_overridesPreviouslyInsertedCacheValues()
     
     func test_delete_hasNoSideEffectsOnEmptyCache()
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index e5fa8c9..e70a6db 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -66,7 +66,9 @@ extension FeedStoreSpecs where Self: XCTestCase {
         expect(sut, toRetrieve: expectedResult, file: file, line: line)
         expect(sut, toRetrieve: expectedResult, file: file, line: line)
     }
-    
+}
+
+extension FeedStoreSpecs where Self: XCTestCase {
     func assertThatRetrieveDeliversEmptyOnEmptyCache(
         on sut: FeedStore,
         file: StaticString = #file,
@@ -106,6 +108,22 @@ extension FeedStoreSpecs where Self: XCTestCase {
         insert((feed, timestamp), to: sut)
         expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
     }
+}
+
+extension FeedStoreSpecs where Self: XCTestCase {
+    func assertThatInsertDeliversNoErrorOnEmptyCache(on sut: FeedStore, file: StaticString = #file, line: UInt = #line) {
+        let insertionError = insert((uniqueImageFeed().local, Date()), to: sut)
+        
+        XCTAssertNil(insertionError, "Expected to insert cache successfully", file: file, line: line)
+    }
+    
+    func assertThatInsertDeliversNoErrorOnNonEmptyCache(on sut: FeedStore, file: StaticString = #file, line: UInt = #line) {
+        insert((uniqueImageFeed().local, Date()), to: sut)
+        
+        let insertionError = insert((uniqueImageFeed().local, Date()), to: sut)
+        
+        XCTAssertNil(insertionError, "Expected to override cache successfully", file: file, line: line)
+    }
     
     func assertThatInsertOverridesPreviouslyInsertedCacheValues(
         on sut: FeedStore,
@@ -122,6 +140,9 @@ extension FeedStoreSpecs where Self: XCTestCase {
         XCTAssertNil(latestInsertionError, "Expected to override cache succesfully")
         expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
     }
+}
+
+extension FeedStoreSpecs where Self: XCTestCase {
     
     func assertThatDeleteHasNoSideEffectOnEmptyCache(
         on sut: FeedStore,

From a01b3f2eec529d85c8e4b94788d536504cdcf2e4 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:18:18 +0200
Subject: [PATCH 119/159] `CoreDataStore.insert()` delivers no error on empty
 cache

---
 .../Feed Cache/CoreDataFeedStoreSpecs.swift                 | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index ce4ce74..eead62b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -29,7 +29,11 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
         assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(on: sut)
     }
     
-    func test_insert_deliversNoErrorOnEmptyCache() {}
+    func test_insert_deliversNoErrorOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatInsertDeliversNoErrorOnEmptyCache(on: sut)
+    }
+    
     func test_insert_deliversNoErrorOnNonEmptyCache() {}
     
     func test_insert_overridesPreviouslyInsertedCacheValues() {

From a93d785450e4c0469d8173c6681eacda64d3ca88 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:19:04 +0200
Subject: [PATCH 120/159] `CoreDataFeedStore.insert()` delivers no error on no
 empty cache

---
 .../Feed Cache/CoreDataFeedStoreSpecs.swift                  | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index eead62b..1d3e9a3 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -34,7 +34,10 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
         assertThatInsertDeliversNoErrorOnEmptyCache(on: sut)
     }
     
-    func test_insert_deliversNoErrorOnNonEmptyCache() {}
+    func test_insert_deliversNoErrorOnNonEmptyCache() {
+        let sut = makeSUT()
+        assertThatInsertDeliversNoErrorOnNonEmptyCache(on: sut)
+    }
     
     func test_insert_overridesPreviouslyInsertedCacheValues() {
     }

From 0da5da4bfe39ac69bfa8cb91f1256984d7a00177 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:23:44 +0200
Subject: [PATCH 121/159] `CoreDataFeedStore.insert()` overrides previously
 inserted cache values

---
 EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift | 7 ++++++-
 .../Feed Cache/CoreDataFeedStoreSpecs.swift                | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index 80c9e07..07eb144 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -38,7 +38,7 @@ public final class CoreDataStore: FeedStore {
     public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
         context.perform { [context] in
             do {
-                let managedCache = ManagedCache(context: context)
+                let managedCache = try ManagedCache.newUniqueInstance(in: context)
                 managedCache.timestamp = timestamp
                 managedCache.feed = ManagedFeedImage.images(
                     from: feed,
@@ -113,6 +113,11 @@ private class ManagedCache: NSManagedObject {
         request.returnsObjectsAsFaults = false
         return try context.fetch(request).first
     }
+    
+    static func newUniqueInstance(in context: NSManagedObjectContext) throws -> ManagedCache {
+        try find(in: context).map(context.delete)
+        return ManagedCache(context: context)
+    }
 }
 
 @objc(ManagedFeedImage)
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 1d3e9a3..19b874e 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -40,6 +40,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_insert_overridesPreviouslyInsertedCacheValues() {
+        let sut = makeSUT()
+        assertThatInsertOverridesPreviouslyInsertedCacheValues(on: sut)
     }
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {

From 4da9ab99d8baf8c7665713d3f23c5f059ad93ff7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:25:23 +0200
Subject: [PATCH 122/159] Add missing delete specs to FeedStoreSpecs

---
 .../EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift  | 3 +++
 .../EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift | 3 +++
 .../EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift         | 2 ++
 3 files changed, 8 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 92f62d1..8c06102 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -71,6 +71,9 @@ class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
         assertThatStoreSideEffectsRunSerially(on: sut)
     }
     
+    func test_delete_deliversNoErrorOnEmptyCache() {}
+    func test_delete_deliversNoErrorOnNonEmptyCache() {}
+    
     // MARK: - Helpers
     private func makeSUT(
         storeURL: URL? = nil,
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 19b874e..d2ccc14 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -44,6 +44,9 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
         assertThatInsertOverridesPreviouslyInsertedCacheValues(on: sut)
     }
     
+    func test_delete_deliversNoErrorOnEmptyCache() {}
+    func test_delete_deliversNoErrorOnNonEmptyCache() {}
+    
     func test_delete_hasNoSideEffectsOnEmptyCache() {
     }
     
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift
index f3ca41b..625a31a 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/FeedStoreSpecs.swift	
@@ -15,6 +15,8 @@ protocol FeedStoreSpecs {
     func test_insert_deliversNoErrorOnNonEmptyCache()
     func test_insert_overridesPreviouslyInsertedCacheValues()
     
+    func test_delete_deliversNoErrorOnEmptyCache()
+    func test_delete_deliversNoErrorOnNonEmptyCache()
     func test_delete_hasNoSideEffectsOnEmptyCache()
     func test_delete_emptiesPreviouslyInsertedCache()
     

From 2eba6fadcea4150c38fcc0cf2ed3f1ef6f80ea05 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:27:32 +0200
Subject: [PATCH 123/159] `CodableFeedStore.delete()` does not deliver errors
 on empty cache

---
 .../Feed Cache/CodableFeedStoreTests.swift             | 10 ++++++++--
 .../Feed Cache/XCTestCase+FeedStoreSpecs.swift         |  6 ++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index 8c06102..a9fec36 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -71,8 +71,14 @@ class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
         assertThatStoreSideEffectsRunSerially(on: sut)
     }
     
-    func test_delete_deliversNoErrorOnEmptyCache() {}
-    func test_delete_deliversNoErrorOnNonEmptyCache() {}
+    func test_delete_deliversNoErrorOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatDeleteDeliversNoErrorOnEmptyCache(on: sut)
+        
+    }
+    
+    func test_delete_deliversNoErrorOnNonEmptyCache() {
+    }
     
     // MARK: - Helpers
     private func makeSUT(
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index e70a6db..b613e7b 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -144,6 +144,12 @@ extension FeedStoreSpecs where Self: XCTestCase {
 
 extension FeedStoreSpecs where Self: XCTestCase {
     
+    func assertThatDeleteDeliversNoErrorOnEmptyCache(on sut: FeedStore, file: StaticString = #file, line: UInt = #line) {
+        let deletionError = deleteCache(from: sut)
+        
+        XCTAssertNil(deletionError, "Expected empty cache deletion to succeed", file: file, line: line)
+    }
+    
     func assertThatDeleteHasNoSideEffectOnEmptyCache(
         on sut: FeedStore,
         file: StaticString = #file,

From 76090075464a30425a3b8a9ac1fcd622a9c72209 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:30:30 +0200
Subject: [PATCH 124/159] `CodableFeedStore.delete()` delivers no error on non
 empty cache

---
 .../Feed Cache/CodableFeedStoreTests.swift                  | 2 ++
 .../Feed Cache/XCTestCase+FeedStoreSpecs.swift              | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
index a9fec36..dc4237e 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
@@ -78,6 +78,8 @@ class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
     }
     
     func test_delete_deliversNoErrorOnNonEmptyCache() {
+        let sut = makeSUT()
+        assertThatDeleteDeliversNoErrorOnNonEmptyCache(on: sut)
     }
     
     // MARK: - Helpers
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index b613e7b..ca96c0f 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -150,6 +150,12 @@ extension FeedStoreSpecs where Self: XCTestCase {
         XCTAssertNil(deletionError, "Expected empty cache deletion to succeed", file: file, line: line)
     }
     
+    func assertThatDeleteDeliversNoErrorOnNonEmptyCache(on sut: FeedStore, file: StaticString = #file, line: UInt = #line) {
+        insert((uniqueImageFeed().local, Date()), to: sut)
+        let deletionError = deleteCache(from: sut)
+        XCTAssertNil(deletionError, "Expected empty cache deletion to succeed", file: file, line: line)
+    }
+    
     func assertThatDeleteHasNoSideEffectOnEmptyCache(
         on sut: FeedStore,
         file: StaticString = #file,

From 9614c9b4b55dde8f6366225ebd5356abd75b3693 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:32:22 +0200
Subject: [PATCH 125/159] `CoreDataStore.delete()` delivers no error on empty
 cache

---
 EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift  | 2 +-
 .../Feed Cache/CoreDataFeedStoreSpecs.swift                 | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index 07eb144..c6e1a63 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -55,7 +55,7 @@ public final class CoreDataStore: FeedStore {
     
     
     public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        
+       completion(nil)
     }
 }
 
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index d2ccc14..7ea59c7 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -44,7 +44,11 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
         assertThatInsertOverridesPreviouslyInsertedCacheValues(on: sut)
     }
     
-    func test_delete_deliversNoErrorOnEmptyCache() {}
+    func test_delete_deliversNoErrorOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatDeleteDeliversNoErrorOnEmptyCache(on: sut)
+    }
+    
     func test_delete_deliversNoErrorOnNonEmptyCache() {}
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {

From 3ccd197516c3bceb963e1c646924de4c67f0de9c Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:33:03 +0200
Subject: [PATCH 126/159] `CoreDataStore.delete()` delivers no error on non
 empty cache

---
 .../Feed Cache/CoreDataFeedStoreSpecs.swift                  | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 7ea59c7..62a48a2 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -49,7 +49,10 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
         assertThatDeleteDeliversNoErrorOnEmptyCache(on: sut)
     }
     
-    func test_delete_deliversNoErrorOnNonEmptyCache() {}
+    func test_delete_deliversNoErrorOnNonEmptyCache() {
+        let sut = makeSUT()
+        assertThatDeleteDeliversNoErrorOnNonEmptyCache(on: sut)
+    }
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {
     }

From e708ae78621625fa5427b116ab3d537145a9ce3d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:34:11 +0200
Subject: [PATCH 127/159] Rename `CoreDataStore` to `CoreDataFeedStore` thus
 adding pertinent domain term that better reflects the specificity of the
 object

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |   8 +-
 .../Feed Cache/CoreDataFeedStore.swift        | 151 ++++++++++++++++++
 .../Feed Cache/CoreDataStore.swift            |   2 +-
 .../Feed Cache/CoreDataFeedStoreSpecs.swift   |   6 +-
 4 files changed, 159 insertions(+), 8 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index c8d9865..308f82e 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -19,7 +19,7 @@
 		407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */; };
 		407F4FCC2DA403330070F56E /* XCTestCase+FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */; };
 		407F4FD12DA530810070F56E /* CoreDataFeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */; };
-		407F4FD32DA531050070F56E /* CoreDataStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD22DA530FF0070F56E /* CoreDataStore.swift */; };
+		407F4FD32DA531050070F56E /* CoreDataFeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */; };
 		40B002492CF9E9DB0058D3E0 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		40B9753B2D9E7AE2009652B5 /* CacheFeedUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */; };
 		40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */; };
@@ -62,7 +62,7 @@
 		407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpecs.swift; sourceTree = "<group>"; };
 		407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "XCTestCase+FeedStoreSpecs.swift"; sourceTree = "<group>"; };
 		407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataFeedStoreSpecs.swift; sourceTree = "<group>"; };
-		407F4FD22DA530FF0070F56E /* CoreDataStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataStore.swift; sourceTree = "<group>"; };
+		407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataFeedStore.swift; sourceTree = "<group>"; };
 		40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedAPIEndToEndTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		40B9753A2D9E7ADB009652B5 /* CacheFeedUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CacheFeedUseCaseTests.swift; sourceTree = "<group>"; };
 		40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalFeedLoader.swift; sourceTree = "<group>"; };
@@ -197,7 +197,7 @@
 		40B975412D9E9FB7009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
-				407F4FD22DA530FF0070F56E /* CoreDataStore.swift */,
+				407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */,
 				40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */,
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
 				407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */,
@@ -373,7 +373,7 @@
 				407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */,
-				407F4FD32DA531050070F56E /* CoreDataStore.swift in Sources */,
+				407F4FD32DA531050070F56E /* CoreDataFeedStore.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift
new file mode 100644
index 0000000..8df61fb
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift	
@@ -0,0 +1,151 @@
+//
+//  CoreDataStore.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 8/4/25.
+//
+
+import CoreData
+
+public final class CoreDataFeedStore: FeedStore {
+    
+    let container: NSPersistentContainer
+    private let context: NSManagedObjectContext
+    public init(storeURL: URL, bundle: Bundle = .main) throws {
+        container = try NSPersistentContainer.load(
+            modelName: "FeedStore",
+            url: storeURL,
+            in: bundle
+        )
+        context = container.newBackgroundContext()
+    }
+    
+    public func retrieve(completion: @escaping RetrievalCompletion) {
+        context.perform { [context] in
+            
+            do {
+                if let cache = try ManagedCache.find(in: context) {
+                    completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
+                } else {
+                    completion(.empty)
+                }
+            } catch {
+                completion(.failure(error))
+            }
+        }
+    }
+
+    public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
+        context.perform { [context] in
+            do {
+                let managedCache = try ManagedCache.newUniqueInstance(in: context)
+                managedCache.timestamp = timestamp
+                managedCache.feed = ManagedFeedImage.images(
+                    from: feed,
+                    in: context
+                )
+                try context.save()
+                completion(nil)
+            } catch {
+                completion(error)
+            }
+        }
+        
+    }
+    
+    
+    public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
+       completion(nil)
+    }
+}
+
+private extension NSPersistentContainer {
+    enum LoadingError: Error {
+        case modelNotFound
+        case failedToPersistentStores(Error)
+    }
+    
+    static func load(
+        modelName name: String,
+        url: URL,
+        in bundle: Bundle
+    ) throws -> NSPersistentContainer {
+        guard let model = NSManagedObjectModel.with(name: name, in: bundle) else { throw LoadingError.modelNotFound }
+        let container = NSPersistentContainer(name: name, managedObjectModel: model)
+        
+        container.persistentStoreDescriptions = [
+            NSPersistentStoreDescription(url: url)
+        ]
+        
+        var loadError: Error?
+        container.loadPersistentStores {
+            loadError = $1
+        }
+        
+        try loadError.map {
+            throw LoadingError.failedToPersistentStores($0)
+        }
+        
+        return container
+    }
+}
+
+private extension NSManagedObjectModel {
+    static func with(name: String, in bundle: Bundle) -> NSManagedObjectModel? {
+        return bundle.url(forResource: name, withExtension: "momd")
+            .flatMap {
+                NSManagedObjectModel(contentsOf: $0)
+            }
+    }
+}
+
+@objc(ManagedCache)
+private class ManagedCache: NSManagedObject {
+    @NSManaged var timestamp: Date
+    @NSManaged var feed: NSOrderedSet
+    
+    var localFeed: [LocalFeedImage] {
+        return feed.compactMap { ($0 as? ManagedFeedImage)?.local }
+    }
+    
+    static func find(in context: NSManagedObjectContext) throws -> ManagedCache? {
+        let request = NSFetchRequest<ManagedCache>(entityName: entity().name!)
+        request.returnsObjectsAsFaults = false
+        return try context.fetch(request).first
+    }
+    
+    static func newUniqueInstance(in context: NSManagedObjectContext) throws -> ManagedCache {
+        try find(in: context).map(context.delete)
+        return ManagedCache(context: context)
+    }
+}
+
+@objc(ManagedFeedImage)
+private class ManagedFeedImage: NSManagedObject {
+    @NSManaged var id: UUID
+    @NSManaged var imageDescription: String?
+    @NSManaged var location: String?
+    @NSManaged var url: URL
+    @NSManaged var cache: ManagedCache
+    
+    static func images(from localFeed: [LocalFeedImage], in context: NSManagedObjectContext) -> NSOrderedSet {
+        let managedFeedImages = localFeed.map {
+            let managedFeedImage = ManagedFeedImage(context: context)
+            managedFeedImage.id = $0.id
+            managedFeedImage.imageDescription = $0.description
+            managedFeedImage.location = $0.location
+            managedFeedImage.url = $0.url
+            return managedFeedImage
+        }
+        return NSOrderedSet(array: managedFeedImages)
+    }
+    
+    var local: LocalFeedImage {
+        LocalFeedImage(
+            id: id,
+            description: imageDescription,
+            location: location,
+            url: url
+        )
+    }
+}
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift
index c6e1a63..8df61fb 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataStore.swift	
@@ -7,7 +7,7 @@
 
 import CoreData
 
-public final class CoreDataStore: FeedStore {
+public final class CoreDataFeedStore: FeedStore {
     
     let container: NSPersistentContainer
     private let context: NSManagedObjectContext
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 62a48a2..5574e1f 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -64,10 +64,10 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     // MARK: - Helpers
-    private func makeSUT(file: StaticString = #file, line: UInt = #line) -> CoreDataStore {
-        let storeBundle = Bundle(for: CoreDataStore.self)
+    private func makeSUT(file: StaticString = #file, line: UInt = #line) -> CoreDataFeedStore {
+        let storeBundle = Bundle(for: CoreDataFeedStore.self)
         let storeURL = URL(fileURLWithPath: "/dev/null")
-        let sut = try! CoreDataStore(
+        let sut = try! CoreDataFeedStore(
             storeURL: storeURL,
             bundle: storeBundle
         )

From b66e6065da46d173076a9a96e6a0bcfc2629f155 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:34:52 +0200
Subject: [PATCH 128/159] `CoreDataFeedStore.delete()` has no side effects on
 empty cache

---
 .../EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift  | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 5574e1f..5652931 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -55,6 +55,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_delete_hasNoSideEffectsOnEmptyCache() {
+        let sut = makeSUT()
+        assertThatDeleteHasNoSideEffectOnEmptyCache(on: sut)
     }
     
     func test_delete_emptiesPreviouslyInsertedCache() {

From cf574bc7159115379aebd4127b80fae5b571728c Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:37:52 +0200
Subject: [PATCH 129/159] `CoreDataFeedStore.delete()` empties previously
 inserted cache

---
 .../EssentialFeed/Feed Cache/CoreDataFeedStore.swift  | 11 ++++++++++-
 .../Feed Cache/CoreDataFeedStoreSpecs.swift           |  2 ++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift
index 8df61fb..b8d2fd3 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift	
@@ -55,7 +55,16 @@ public final class CoreDataFeedStore: FeedStore {
     
     
     public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-       completion(nil)
+        context.perform { [context] in
+            do {
+                try ManagedCache.find(in: context)
+                    .map(context.delete)
+                    .map(context.save)
+                completion(nil)
+            } catch {
+                completion(error)
+            }
+        }
     }
 }
 
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index 5652931..fbffc38 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -60,6 +60,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_delete_emptiesPreviouslyInsertedCache() {
+        let sut = makeSUT()
+        assertThatDeleteEmptiesPreviouslyInsertedCache(on: sut)
     }
     
     func test_storeSideEffects_runSerially() {

From a3cec19c3313c687b7b6e5a2c87611e4f24c6a5f Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 10:39:05 +0200
Subject: [PATCH 130/159] Proved that `CoreDataFeedStore` side-effects run
 serially

---
 .../EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift  | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift
index fbffc38..7f7ac9e 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CoreDataFeedStoreSpecs.swift	
@@ -65,6 +65,8 @@ class CoreDataFeedStoreSpecs: XCTestCase, FeedStoreSpecs {
     }
     
     func test_storeSideEffects_runSerially() {
+        let sut = makeSUT()
+        assertThatStoreSideEffectsRunSerially(on: sut)
     }
     
     // MARK: - Helpers

From c6fe8a19f5918901b93f13adbdbbf8efc1e6e646 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:10:25 +0200
Subject: [PATCH 131/159] Extract duplicate code into reusable helper method

---
 .../EssentialFeed/Feed Cache/CoreDataFeedStore.swift | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift
index b8d2fd3..c218b4f 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift	
@@ -21,7 +21,7 @@ public final class CoreDataFeedStore: FeedStore {
     }
     
     public func retrieve(completion: @escaping RetrievalCompletion) {
-        context.perform { [context] in
+        perform { context in
             
             do {
                 if let cache = try ManagedCache.find(in: context) {
@@ -36,7 +36,7 @@ public final class CoreDataFeedStore: FeedStore {
     }
 
     public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-        context.perform { [context] in
+        perform { context in
             do {
                 let managedCache = try ManagedCache.newUniqueInstance(in: context)
                 managedCache.timestamp = timestamp
@@ -55,7 +55,7 @@ public final class CoreDataFeedStore: FeedStore {
     
     
     public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        context.perform { [context] in
+        perform { context in
             do {
                 try ManagedCache.find(in: context)
                     .map(context.delete)
@@ -66,6 +66,12 @@ public final class CoreDataFeedStore: FeedStore {
             }
         }
     }
+    
+    private func perform(_ action: @escaping (NSManagedObjectContext) -> Void) {
+        context.perform { [context] in
+            action(context)
+        }
+    }
 }
 
 private extension NSPersistentContainer {

From 64ac31f81ca7ed7c98855636156a3e84a5a34b31 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:12:04 +0200
Subject: [PATCH 132/159] Move `CoreDataFeedStore` and `CodableFeedStore` files
 to the new infrastructure folder

---
 .../EssentialFeed.xcodeproj/project.pbxproj   | 22 ++++++++++++++++---
 .../CodableFeedStore.swift                    |  0
 .../CoreData}/CoreDataFeedStore.swift         |  0
 .../FeedStore.xcdatamodel/contents            |  0
 4 files changed, 19 insertions(+), 3 deletions(-)
 rename EssentialFeed/EssentialFeed/Feed Cache/{ => Infrastructure}/CodableFeedStore.swift (100%)
 rename EssentialFeed/EssentialFeed/Feed Cache/{ => Infrastructure/CoreData}/CoreDataFeedStore.swift (100%)
 rename EssentialFeed/EssentialFeed/Feed Cache/{ => Infrastructure/CoreData}/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents (100%)

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 308f82e..5efc976 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -179,6 +179,24 @@
 			path = "Feed Feature";
 			sourceTree = "<group>";
 		};
+		40412A1A2DA67130004677C4 /* Infrastructure */ = {
+			isa = PBXGroup;
+			children = (
+				40412A1B2DA67135004677C4 /* CoreData */,
+				407F4FB02DA022C00070F56E /* CodableFeedStore.swift */,
+			);
+			path = Infrastructure;
+			sourceTree = "<group>";
+		};
+		40412A1B2DA67135004677C4 /* CoreData */ = {
+			isa = PBXGroup;
+			children = (
+				407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */,
+				40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */,
+			);
+			path = CoreData;
+			sourceTree = "<group>";
+		};
 		40B975392D9E7AD3009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
@@ -197,13 +215,11 @@
 		40B975412D9E9FB7009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
-				407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */,
-				40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */,
+				40412A1A2DA67130004677C4 /* Infrastructure */,
 				40B975422D9E9FC4009652B5 /* LocalFeedLoader.swift */,
 				407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */,
 				40B975442D9EA01D009652B5 /* FeedStore.swift */,
 				40B975482D9EA7A2009652B5 /* LocalFeedImage.swift */,
-				407F4FB02DA022C00070F56E /* CodableFeedStore.swift */,
 			);
 			path = "Feed Cache";
 			sourceTree = "<group>";
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CodableFeedStore.swift
similarity index 100%
rename from EssentialFeed/EssentialFeed/Feed Cache/CodableFeedStore.swift
rename to EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CodableFeedStore.swift
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
similarity index 100%
rename from EssentialFeed/EssentialFeed/Feed Cache/CoreDataFeedStore.swift
rename to EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents
similarity index 100%
rename from EssentialFeed/EssentialFeed/Feed Cache/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents
rename to EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/FeedStore.xcdatamodeld/FeedStore.xcdatamodel/contents

From 84ed2039dd50882454836644cf0aa27bc755b698 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:13:38 +0200
Subject: [PATCH 133/159] Extract reusable CoreData heleprs into a separate
 file

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  4 ++
 .../CoreData/CoreDataFeedStore.swift          | 40 ----------------
 .../CoreData/CoreDataHelpers.swift            | 48 +++++++++++++++++++
 3 files changed, 52 insertions(+), 40 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataHelpers.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 5efc976..85dd983 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -11,6 +11,7 @@
 		080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0B21B6DAE800813479 /* FeedImage.swift */; };
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		40412A172DA65403004677C4 /* FeedStore.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */; };
+		40412A1D2DA6719E004677C4 /* CoreDataHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
@@ -54,6 +55,7 @@
 		080EDF0B21B6DAE800813479 /* FeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedImage.swift; sourceTree = "<group>"; };
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		40412A162DA65403004677C4 /* FeedStore.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = FeedStore.xcdatamodel; sourceTree = "<group>"; };
+		40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataHelpers.swift; sourceTree = "<group>"; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
@@ -191,6 +193,7 @@
 		40412A1B2DA67135004677C4 /* CoreData */ = {
 			isa = PBXGroup;
 			children = (
+				40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */,
 				407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */,
 				40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */,
 			);
@@ -382,6 +385,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				40412A1D2DA6719E004677C4 /* CoreDataHelpers.swift in Sources */,
 				40412A172DA65403004677C4 /* FeedStore.xcdatamodeld in Sources */,
 				080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */,
 				080EDF0C21B6DAE800813479 /* FeedImage.swift in Sources */,
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
index c218b4f..c8a8943 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
@@ -74,46 +74,6 @@ public final class CoreDataFeedStore: FeedStore {
     }
 }
 
-private extension NSPersistentContainer {
-    enum LoadingError: Error {
-        case modelNotFound
-        case failedToPersistentStores(Error)
-    }
-    
-    static func load(
-        modelName name: String,
-        url: URL,
-        in bundle: Bundle
-    ) throws -> NSPersistentContainer {
-        guard let model = NSManagedObjectModel.with(name: name, in: bundle) else { throw LoadingError.modelNotFound }
-        let container = NSPersistentContainer(name: name, managedObjectModel: model)
-        
-        container.persistentStoreDescriptions = [
-            NSPersistentStoreDescription(url: url)
-        ]
-        
-        var loadError: Error?
-        container.loadPersistentStores {
-            loadError = $1
-        }
-        
-        try loadError.map {
-            throw LoadingError.failedToPersistentStores($0)
-        }
-        
-        return container
-    }
-}
-
-private extension NSManagedObjectModel {
-    static func with(name: String, in bundle: Bundle) -> NSManagedObjectModel? {
-        return bundle.url(forResource: name, withExtension: "momd")
-            .flatMap {
-                NSManagedObjectModel(contentsOf: $0)
-            }
-    }
-}
-
 @objc(ManagedCache)
 private class ManagedCache: NSManagedObject {
     @NSManaged var timestamp: Date
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataHelpers.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataHelpers.swift
new file mode 100644
index 0000000..9f6053f
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataHelpers.swift	
@@ -0,0 +1,48 @@
+//
+//  CoreDataHelpers.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 9/4/25.
+//
+
+import CoreData
+
+extension NSPersistentContainer {
+    enum LoadingError: Error {
+        case modelNotFound
+        case failedToPersistentStores(Error)
+    }
+    
+    static func load(
+        modelName name: String,
+        url: URL,
+        in bundle: Bundle
+    ) throws -> NSPersistentContainer {
+        guard let model = NSManagedObjectModel.with(name: name, in: bundle) else { throw LoadingError.modelNotFound }
+        let container = NSPersistentContainer(name: name, managedObjectModel: model)
+        
+        container.persistentStoreDescriptions = [
+            NSPersistentStoreDescription(url: url)
+        ]
+        
+        var loadError: Error?
+        container.loadPersistentStores {
+            loadError = $1
+        }
+        
+        try loadError.map {
+            throw LoadingError.failedToPersistentStores($0)
+        }
+        
+        return container
+    }
+}
+
+private extension NSManagedObjectModel {
+    static func with(name: String, in bundle: Bundle) -> NSManagedObjectModel? {
+        return bundle.url(forResource: name, withExtension: "momd")
+            .flatMap {
+                NSManagedObjectModel(contentsOf: $0)
+            }
+    }
+}

From 945032d044309838f20e379c82877fc3071a33b5 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:16:21 +0200
Subject: [PATCH 134/159] Extract CoreData managed classes into separate files

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  8 +++
 .../CoreData/CoreDataFeedStore.swift          | 51 -------------------
 .../CoreData/ManagedCache.swift               | 29 +++++++++++
 .../CoreData/ManagedFeedImage.swift           | 38 ++++++++++++++
 4 files changed, 75 insertions(+), 51 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift
 create mode 100644 EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 85dd983..25d1447 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -12,6 +12,8 @@
 		080EDF0E21B6DCB600813479 /* FeedLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 080EDF0D21B6DCB600813479 /* FeedLoader.swift */; };
 		40412A172DA65403004677C4 /* FeedStore.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */; };
 		40412A1D2DA6719E004677C4 /* CoreDataHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */; };
+		40412A1F2DA67227004677C4 /* ManagedCache.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A1E2DA67223004677C4 /* ManagedCache.swift */; };
+		40412A212DA67241004677C4 /* ManagedFeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A202DA6723E004677C4 /* ManagedFeedImage.swift */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
@@ -56,6 +58,8 @@
 		080EDF0D21B6DCB600813479 /* FeedLoader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedLoader.swift; sourceTree = "<group>"; };
 		40412A162DA65403004677C4 /* FeedStore.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = FeedStore.xcdatamodel; sourceTree = "<group>"; };
 		40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataHelpers.swift; sourceTree = "<group>"; };
+		40412A1E2DA67223004677C4 /* ManagedCache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ManagedCache.swift; sourceTree = "<group>"; };
+		40412A202DA6723E004677C4 /* ManagedFeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ManagedFeedImage.swift; sourceTree = "<group>"; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
@@ -193,6 +197,8 @@
 		40412A1B2DA67135004677C4 /* CoreData */ = {
 			isa = PBXGroup;
 			children = (
+				40412A202DA6723E004677C4 /* ManagedFeedImage.swift */,
+				40412A1E2DA67223004677C4 /* ManagedCache.swift */,
 				40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */,
 				407F4FD22DA530FF0070F56E /* CoreDataFeedStore.swift */,
 				40412A152DA65403004677C4 /* FeedStore.xcdatamodeld */,
@@ -394,7 +400,9 @@
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
 				407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */,
 				407F4FD32DA531050070F56E /* CoreDataFeedStore.swift in Sources */,
+				40412A1F2DA67227004677C4 /* ManagedCache.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
+				40412A212DA67241004677C4 /* ManagedFeedImage.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
index c8a8943..0a73608 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
@@ -73,54 +73,3 @@ public final class CoreDataFeedStore: FeedStore {
         }
     }
 }
-
-@objc(ManagedCache)
-private class ManagedCache: NSManagedObject {
-    @NSManaged var timestamp: Date
-    @NSManaged var feed: NSOrderedSet
-    
-    var localFeed: [LocalFeedImage] {
-        return feed.compactMap { ($0 as? ManagedFeedImage)?.local }
-    }
-    
-    static func find(in context: NSManagedObjectContext) throws -> ManagedCache? {
-        let request = NSFetchRequest<ManagedCache>(entityName: entity().name!)
-        request.returnsObjectsAsFaults = false
-        return try context.fetch(request).first
-    }
-    
-    static func newUniqueInstance(in context: NSManagedObjectContext) throws -> ManagedCache {
-        try find(in: context).map(context.delete)
-        return ManagedCache(context: context)
-    }
-}
-
-@objc(ManagedFeedImage)
-private class ManagedFeedImage: NSManagedObject {
-    @NSManaged var id: UUID
-    @NSManaged var imageDescription: String?
-    @NSManaged var location: String?
-    @NSManaged var url: URL
-    @NSManaged var cache: ManagedCache
-    
-    static func images(from localFeed: [LocalFeedImage], in context: NSManagedObjectContext) -> NSOrderedSet {
-        let managedFeedImages = localFeed.map {
-            let managedFeedImage = ManagedFeedImage(context: context)
-            managedFeedImage.id = $0.id
-            managedFeedImage.imageDescription = $0.description
-            managedFeedImage.location = $0.location
-            managedFeedImage.url = $0.url
-            return managedFeedImage
-        }
-        return NSOrderedSet(array: managedFeedImages)
-    }
-    
-    var local: LocalFeedImage {
-        LocalFeedImage(
-            id: id,
-            description: imageDescription,
-            location: location,
-            url: url
-        )
-    }
-}
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift
new file mode 100644
index 0000000..5791986
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift	
@@ -0,0 +1,29 @@
+//
+//  ManagedCache.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 9/4/25.
+//
+
+import CoreData
+
+@objc(ManagedCache)
+class ManagedCache: NSManagedObject {
+    @NSManaged var timestamp: Date
+    @NSManaged var feed: NSOrderedSet
+    
+    var localFeed: [LocalFeedImage] {
+        return feed.compactMap { ($0 as? ManagedFeedImage)?.local }
+    }
+    
+    static func find(in context: NSManagedObjectContext) throws -> ManagedCache? {
+        let request = NSFetchRequest<ManagedCache>(entityName: entity().name!)
+        request.returnsObjectsAsFaults = false
+        return try context.fetch(request).first
+    }
+    
+    static func newUniqueInstance(in context: NSManagedObjectContext) throws -> ManagedCache {
+        try find(in: context).map(context.delete)
+        return ManagedCache(context: context)
+    }
+}
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift
new file mode 100644
index 0000000..c86f016
--- /dev/null
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift	
@@ -0,0 +1,38 @@
+//
+//  ManagedFeedImage.swift
+//  EssentialFeed
+//
+//  Created by Cristian Felipe Patiño Rojas on 9/4/25.
+//
+
+import CoreData
+
+@objc(ManagedFeedImage)
+class ManagedFeedImage: NSManagedObject {
+    @NSManaged var id: UUID
+    @NSManaged var imageDescription: String?
+    @NSManaged var location: String?
+    @NSManaged var url: URL
+    @NSManaged var cache: ManagedCache
+    
+    static func images(from localFeed: [LocalFeedImage], in context: NSManagedObjectContext) -> NSOrderedSet {
+        let managedFeedImages = localFeed.map {
+            let managedFeedImage = ManagedFeedImage(context: context)
+            managedFeedImage.id = $0.id
+            managedFeedImage.imageDescription = $0.description
+            managedFeedImage.location = $0.location
+            managedFeedImage.url = $0.url
+            return managedFeedImage
+        }
+        return NSOrderedSet(array: managedFeedImages)
+    }
+    
+    var local: LocalFeedImage {
+        LocalFeedImage(
+            id: id,
+            description: imageDescription,
+            location: location,
+            url: url
+        )
+    }
+}

From 6095f8b3ad2df7369e12a91186899d65ef591625 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:17:29 +0200
Subject: [PATCH 135/159] Separate CoreData managed model classes data from
 helpers with extensions

---
 .../Feed Cache/Infrastructure/CoreData/ManagedCache.swift     | 4 +++-
 .../Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift | 3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift
index 5791986..d712a19 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedCache.swift	
@@ -11,7 +11,9 @@ import CoreData
 class ManagedCache: NSManagedObject {
     @NSManaged var timestamp: Date
     @NSManaged var feed: NSOrderedSet
-    
+}
+
+extension ManagedCache {
     var localFeed: [LocalFeedImage] {
         return feed.compactMap { ($0 as? ManagedFeedImage)?.local }
     }
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift
index c86f016..03bda54 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/ManagedFeedImage.swift	
@@ -14,6 +14,9 @@ class ManagedFeedImage: NSManagedObject {
     @NSManaged var location: String?
     @NSManaged var url: URL
     @NSManaged var cache: ManagedCache
+}
+
+extension ManagedFeedImage {
     
     static func images(from localFeed: [LocalFeedImage], in context: NSManagedObjectContext) -> NSOrderedSet {
         let managedFeedImages = localFeed.map {

From cd5df45038ba6dfccbe8807b10a62a651da147e5 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:26:19 +0200
Subject: [PATCH 136/159] Add cache integration test test target

---
 .../EssentialFeed.xcodeproj/project.pbxproj   | 116 +++++++++++++++++-
 ...ssentialFeedCacheIntegrationTests.xcscheme |  55 +++++++++
 .../EssentialFeedCacheIntegrationTests.swift  |  12 ++
 3 files changed, 182 insertions(+), 1 deletion(-)
 create mode 100644 EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme
 create mode 100644 EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 25d1447..2467766 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -14,6 +14,7 @@
 		40412A1D2DA6719E004677C4 /* CoreDataHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */; };
 		40412A1F2DA67227004677C4 /* ManagedCache.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A1E2DA67223004677C4 /* ManagedCache.swift */; };
 		40412A212DA67241004677C4 /* ManagedFeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A202DA6723E004677C4 /* ManagedFeedImage.swift */; };
+		40412A4E2DA67465004677C4 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
@@ -40,6 +41,13 @@
 			remoteGlobalIDString = 080EDEF021B6DA7E00813479;
 			remoteInfo = EssentialFeed;
 		};
+		40412A4F2DA67465004677C4 /* PBXContainerItemProxy */ = {
+			isa = PBXContainerItemProxy;
+			containerPortal = 080EDEE821B6DA7E00813479 /* Project object */;
+			proxyType = 1;
+			remoteGlobalIDString = 080EDEF021B6DA7E00813479;
+			remoteInfo = EssentialFeed;
+		};
 		40B0024A2CF9E9DB0058D3E0 /* PBXContainerItemProxy */ = {
 			isa = PBXContainerItemProxy;
 			containerPortal = 080EDEE821B6DA7E00813479 /* Project object */;
@@ -60,6 +68,7 @@
 		40412A1C2DA6719B004677C4 /* CoreDataHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataHelpers.swift; sourceTree = "<group>"; };
 		40412A1E2DA67223004677C4 /* ManagedCache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ManagedCache.swift; sourceTree = "<group>"; };
 		40412A202DA6723E004677C4 /* ManagedFeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ManagedFeedImage.swift; sourceTree = "<group>"; };
+		40412A4A2DA67465004677C4 /* EssentialFeedCacheIntegrationTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedCacheIntegrationTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
@@ -102,6 +111,7 @@
 
 /* Begin PBXFileSystemSynchronizedRootGroup section */
 		40124C322CF8BDD5008BBDB6 /* Feed Api */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = "Feed Api"; sourceTree = "<group>"; };
+		40412A4B2DA67465004677C4 /* EssentialFeedCacheIntegrationTests */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = EssentialFeedCacheIntegrationTests; sourceTree = "<group>"; };
 		40B002462CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = EssentialFeedAPIEndToEndTests; sourceTree = "<group>"; };
 		40B9753D2D9E7CB2009652B5 /* Helpers */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = Helpers; sourceTree = "<group>"; };
 		40C57D7A2CF7C16E00518522 /* FeedApi */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40C57D7D2CF7C19100518522 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = FeedApi; sourceTree = "<group>"; };
@@ -123,6 +133,14 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		40412A472DA67465004677C4 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				40412A4E2DA67465004677C4 /* EssentialFeed.framework in Frameworks */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		40B002422CF9E9DB0058D3E0 /* Frameworks */ = {
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
@@ -140,6 +158,7 @@
 				080EDEF321B6DA7E00813479 /* EssentialFeed */,
 				080EDEFE21B6DA7E00813479 /* EssentialFeedTests */,
 				40B002462CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */,
+				40412A4B2DA67465004677C4 /* EssentialFeedCacheIntegrationTests */,
 				080EDEF221B6DA7E00813479 /* Products */,
 			);
 			sourceTree = "<group>";
@@ -150,6 +169,7 @@
 				080EDEF121B6DA7E00813479 /* EssentialFeed.framework */,
 				080EDEFA21B6DA7E00813479 /* EssentialFeedTests.xctest */,
 				40B002452CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests.xctest */,
+				40412A4A2DA67465004677C4 /* EssentialFeedCacheIntegrationTests.xctest */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -295,6 +315,29 @@
 			productReference = 080EDEFA21B6DA7E00813479 /* EssentialFeedTests.xctest */;
 			productType = "com.apple.product-type.bundle.unit-test";
 		};
+		40412A492DA67465004677C4 /* EssentialFeedCacheIntegrationTests */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 40412A532DA67465004677C4 /* Build configuration list for PBXNativeTarget "EssentialFeedCacheIntegrationTests" */;
+			buildPhases = (
+				40412A462DA67465004677C4 /* Sources */,
+				40412A472DA67465004677C4 /* Frameworks */,
+				40412A482DA67465004677C4 /* Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+				40412A502DA67465004677C4 /* PBXTargetDependency */,
+			);
+			fileSystemSynchronizedGroups = (
+				40412A4B2DA67465004677C4 /* EssentialFeedCacheIntegrationTests */,
+			);
+			name = EssentialFeedCacheIntegrationTests;
+			packageProductDependencies = (
+			);
+			productName = EssentialFeedCacheIntegrationTests;
+			productReference = 40412A4A2DA67465004677C4 /* EssentialFeedCacheIntegrationTests.xctest */;
+			productType = "com.apple.product-type.bundle.unit-test";
+		};
 		40B002442CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */ = {
 			isa = PBXNativeTarget;
 			buildConfigurationList = 40B0024C2CF9E9DB0058D3E0 /* Build configuration list for PBXNativeTarget "EssentialFeedAPIEndToEndTests" */;
@@ -325,7 +368,7 @@
 			isa = PBXProject;
 			attributes = {
 				BuildIndependentTargetsInParallel = YES;
-				LastSwiftUpdateCheck = 1600;
+				LastSwiftUpdateCheck = 1620;
 				LastUpgradeCheck = 1600;
 				ORGANIZATIONNAME = "";
 				TargetAttributes = {
@@ -337,6 +380,9 @@
 						CreatedOnToolsVersion = 10.1;
 						LastSwiftMigration = 1540;
 					};
+					40412A492DA67465004677C4 = {
+						CreatedOnToolsVersion = 16.2;
+					};
 					40B002442CF9E9DB0058D3E0 = {
 						CreatedOnToolsVersion = 16.0;
 					};
@@ -358,6 +404,7 @@
 				080EDEF021B6DA7E00813479 /* EssentialFeed */,
 				080EDEF921B6DA7E00813479 /* EssentialFeedTests */,
 				40B002442CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */,
+				40412A492DA67465004677C4 /* EssentialFeedCacheIntegrationTests */,
 			);
 		};
 /* End PBXProject section */
@@ -377,6 +424,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		40412A482DA67465004677C4 /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		40B002432CF9E9DB0058D3E0 /* Resources */ = {
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -422,6 +476,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		40412A462DA67465004677C4 /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		40B002412CF9E9DB0058D3E0 /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -437,6 +498,11 @@
 			target = 080EDEF021B6DA7E00813479 /* EssentialFeed */;
 			targetProxy = 080EDEFC21B6DA7E00813479 /* PBXContainerItemProxy */;
 		};
+		40412A502DA67465004677C4 /* PBXTargetDependency */ = {
+			isa = PBXTargetDependency;
+			target = 080EDEF021B6DA7E00813479 /* EssentialFeed */;
+			targetProxy = 40412A4F2DA67465004677C4 /* PBXContainerItemProxy */;
+		};
 		40B0024B2CF9E9DB0058D3E0 /* PBXTargetDependency */ = {
 			isa = PBXTargetDependency;
 			target = 080EDEF021B6DA7E00813479 /* EssentialFeed */;
@@ -680,6 +746,45 @@
 			};
 			name = Release;
 		};
+		40412A512DA67465004677C4 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_TEAM = V73WZ9Y4HH;
+				GCC_C_LANGUAGE_STANDARD = gnu17;
+				GENERATE_INFOPLIST_FILE = YES;
+				LOCALIZATION_PREFERS_STRING_CATALOGS = YES;
+				MACOSX_DEPLOYMENT_TARGET = 15.0;
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = me.crisfe.EssentialFeedCacheIntegrationTests;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_ACTIVE_COMPILATION_CONDITIONS = "DEBUG $(inherited)";
+				SWIFT_EMIT_LOC_STRINGS = NO;
+				SWIFT_VERSION = 5.0;
+			};
+			name = Debug;
+		};
+		40412A522DA67465004677C4 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_TEAM = V73WZ9Y4HH;
+				GCC_C_LANGUAGE_STANDARD = gnu17;
+				GENERATE_INFOPLIST_FILE = YES;
+				LOCALIZATION_PREFERS_STRING_CATALOGS = YES;
+				MACOSX_DEPLOYMENT_TARGET = 15.0;
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = me.crisfe.EssentialFeedCacheIntegrationTests;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_EMIT_LOC_STRINGS = NO;
+				SWIFT_VERSION = 5.0;
+			};
+			name = Release;
+		};
 		40B0024D2CF9E9DB0058D3E0 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
@@ -749,6 +854,15 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		40412A532DA67465004677C4 /* Build configuration list for PBXNativeTarget "EssentialFeedCacheIntegrationTests" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				40412A512DA67465004677C4 /* Debug */,
+				40412A522DA67465004677C4 /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 		40B0024C2CF9E9DB0058D3E0 /* Build configuration list for PBXNativeTarget "EssentialFeedAPIEndToEndTests" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
diff --git a/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme b/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme
new file mode 100644
index 0000000..2dba0a7
--- /dev/null
+++ b/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme
@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1620"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO"
+            parallelizable = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "40412A492DA67465004677C4"
+               BuildableName = "EssentialFeedCacheIntegrationTests.xctest"
+               BlueprintName = "EssentialFeedCacheIntegrationTests"
+               ReferencedContainer = "container:EssentialFeed.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
new file mode 100644
index 0000000..0833fb0
--- /dev/null
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -0,0 +1,12 @@
+//
+//  EssentialFeedCacheIntegrationTests.swift
+//  EssentialFeedCacheIntegrationTests
+//
+//  Created by Cristian Felipe Patiño Rojas on 9/4/25.
+//
+
+import XCTest
+
+final class EssentialFeedCacheIntegrationTests: XCTestCase {
+    
+}

From f3e49d7ac5dc210188bafd0eaa2995498c8c44c2 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:28:30 +0200
Subject: [PATCH 137/159] Randomize test exectuion order on cache integration
 tests

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  2 ++
 ...ssentialFeedCacheIntegrationTests.xcscheme |  9 +++++--
 ...entialFeedCacheIntegrationTests.xctestplan | 25 +++++++++++++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 2467766..7e1f208 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -69,6 +69,7 @@
 		40412A1E2DA67223004677C4 /* ManagedCache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ManagedCache.swift; sourceTree = "<group>"; };
 		40412A202DA6723E004677C4 /* ManagedFeedImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ManagedFeedImage.swift; sourceTree = "<group>"; };
 		40412A4A2DA67465004677C4 /* EssentialFeedCacheIntegrationTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = EssentialFeedCacheIntegrationTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
+		40412A542DA6750C004677C4 /* EssentialFeedCacheIntegrationTests.xctestplan */ = {isa = PBXFileReference; lastKnownFileType = text; path = EssentialFeedCacheIntegrationTests.xctestplan; sourceTree = "<group>"; };
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
@@ -155,6 +156,7 @@
 		080EDEE721B6DA7E00813479 = {
 			isa = PBXGroup;
 			children = (
+				40412A542DA6750C004677C4 /* EssentialFeedCacheIntegrationTests.xctestplan */,
 				080EDEF321B6DA7E00813479 /* EssentialFeed */,
 				080EDEFE21B6DA7E00813479 /* EssentialFeedTests */,
 				40B002462CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */,
diff --git a/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme b/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme
index 2dba0a7..e950f52 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme
+++ b/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/EssentialFeedCacheIntegrationTests.xcscheme
@@ -11,8 +11,13 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      shouldUseLaunchSchemeArgsEnv = "YES"
-      shouldAutocreateTestPlan = "YES">
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <TestPlans>
+         <TestPlanReference
+            reference = "container:EssentialFeedCacheIntegrationTests.xctestplan"
+            default = "YES">
+         </TestPlanReference>
+      </TestPlans>
       <Testables>
          <TestableReference
             skipped = "NO"
diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan b/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan
new file mode 100644
index 0000000..8774989
--- /dev/null
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan
@@ -0,0 +1,25 @@
+{
+  "configurations" : [
+    {
+      "id" : "278ED14E-66BA-4B7E-8D9C-11AD8033655C",
+      "name" : "Test Scheme Action",
+      "options" : {
+
+      }
+    }
+  ],
+  "defaultOptions" : {
+    "testExecutionOrdering" : "random"
+  },
+  "testTargets" : [
+    {
+      "parallelizable" : true,
+      "target" : {
+        "containerPath" : "container:EssentialFeed.xcodeproj",
+        "identifier" : "40412A492DA67465004677C4",
+        "name" : "EssentialFeedCacheIntegrationTests"
+      }
+    }
+  ],
+  "version" : 1
+}

From 67ce5bc12d2571fc17ef2951de95f98aee975d80 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:29:59 +0200
Subject: [PATCH 138/159] Gather coverage on cache integration tests for the
 EssentialFeed target

---
 .../EssentialFeedCacheIntegrationTests.xctestplan        | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan b/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan
index 8774989..3016214 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests.xctestplan
@@ -9,6 +9,15 @@
     }
   ],
   "defaultOptions" : {
+    "codeCoverage" : {
+      "targets" : [
+        {
+          "containerPath" : "container:EssentialFeed.xcodeproj",
+          "identifier" : "080EDEF021B6DA7E00813479",
+          "name" : "EssentialFeed"
+        }
+      ]
+    },
     "testExecutionOrdering" : "random"
   },
   "testTargets" : [

From b8e181e9932d756eb71bdd35b8dd03b3a7796b9f Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:46:10 +0200
Subject: [PATCH 139/159] Include memory leak tracking helper in the cache
 integration test targets

---
 EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 7e1f208..00423ed 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -89,6 +89,13 @@
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
+		40412A562DA678BE004677C4 /* PBXFileSystemSynchronizedBuildFileExceptionSet */ = {
+			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
+			membershipExceptions = (
+				"XCTestCase+MemoryLeakTrackingHelper.swift",
+			);
+			target = 40412A492DA67465004677C4 /* EssentialFeedCacheIntegrationTests */;
+		};
 		40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */ = {
 			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
 			membershipExceptions = (

From b41456b3742971dd9761119110318f8997e2b23b Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:46:46 +0200
Subject: [PATCH 140/159] `LocalFeedLoader` in integration with the
 `CoreDataFeedStore` delivers no items on empty cache

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |  2 +-
 .../EssentialFeedCacheIntegrationTests.swift  | 43 +++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 00423ed..dafc120 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -121,7 +121,7 @@
 		40124C322CF8BDD5008BBDB6 /* Feed Api */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = "Feed Api"; sourceTree = "<group>"; };
 		40412A4B2DA67465004677C4 /* EssentialFeedCacheIntegrationTests */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = EssentialFeedCacheIntegrationTests; sourceTree = "<group>"; };
 		40B002462CF9E9DB0058D3E0 /* EssentialFeedAPIEndToEndTests */ = {isa = PBXFileSystemSynchronizedRootGroup; explicitFileTypes = {}; explicitFolders = (); path = EssentialFeedAPIEndToEndTests; sourceTree = "<group>"; };
-		40B9753D2D9E7CB2009652B5 /* Helpers */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = Helpers; sourceTree = "<group>"; };
+		40B9753D2D9E7CB2009652B5 /* Helpers */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40B975402D9E7CB2009652B5 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, 40412A562DA678BE004677C4 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = Helpers; sourceTree = "<group>"; };
 		40C57D7A2CF7C16E00518522 /* FeedApi */ = {isa = PBXFileSystemSynchronizedRootGroup; exceptions = (40C57D7D2CF7C19100518522 /* PBXFileSystemSynchronizedBuildFileExceptionSet */, ); explicitFileTypes = {}; explicitFolders = (); path = FeedApi; sourceTree = "<group>"; };
 /* End PBXFileSystemSynchronizedRootGroup section */
 
diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index 0833fb0..3cd556c 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -6,7 +6,50 @@
 //
 
 import XCTest
+import EssentialFeed
 
 final class EssentialFeedCacheIntegrationTests: XCTestCase {
+   
+    func test_load_deliversNoItemsOnEmptyCache() {
+        let sut = makeSUT()
+        
+        let exp = expectation(description: "Wait for load completion")
+        sut.load { result in
+            exp.fulfill()
+            switch result {
+            case let .success(imageFeed):
+                XCTAssertEqual(imageFeed, [], "Expected empty feed")
+            case let .failure(error):
+                XCTFail("Expected successful feed result, got \(error) instead")
+            }
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
     
+    // MARK: - Helpers
+    
+    private func makeSUT(file: StaticString = #file, line: UInt = #line) -> LocalFeedLoader {
+        let storeBundle = Bundle(for: CoreDataFeedStore.self)
+        let storeURL = testSpecificStoreURL()
+        let store = try! CoreDataFeedStore(
+            storeURL: storeURL,
+            bundle: storeBundle
+        )
+        let sut = LocalFeedLoader(
+            store: store,
+            currentDate: Date.init
+        )
+        trackForMemoryLeaks(sut, file: file, line: line)
+        trackForMemoryLeaks(store, file: file, line: line)
+        return sut
+    }
+    
+    private func testSpecificStoreURL() -> URL {
+        return cachesDirectory().appendingPathComponent("\(type(of: self)).store")
+    }
+    
+    private func cachesDirectory() -> URL {
+        return FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!
+    }
 }

From 1caa8e6a999a266b47b11e575fe1cb8ee8b6649a Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:55:14 +0200
Subject: [PATCH 141/159] Include cache test helpers in the cache integration
 tests target

---
 EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index dafc120..90edca3 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -15,6 +15,7 @@
 		40412A1F2DA67227004677C4 /* ManagedCache.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A1E2DA67223004677C4 /* ManagedCache.swift */; };
 		40412A212DA67241004677C4 /* ManagedFeedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40412A202DA6723E004677C4 /* ManagedFeedImage.swift */; };
 		40412A4E2DA67465004677C4 /* EssentialFeed.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 080EDEF121B6DA7E00813479 /* EssentialFeed.framework */; };
+		40412A572DA67A9F004677C4 /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
@@ -92,6 +93,7 @@
 		40412A562DA678BE004677C4 /* PBXFileSystemSynchronizedBuildFileExceptionSet */ = {
 			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
 			membershipExceptions = (
+				SharedTestHelpers.swift,
 				"XCTestCase+MemoryLeakTrackingHelper.swift",
 			);
 			target = 40412A492DA67465004677C4 /* EssentialFeedCacheIntegrationTests */;
@@ -489,6 +491,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				40412A572DA67A9F004677C4 /* FeedCacheTestHelpers.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

From f33c3ca27a633bce1774352279d7d54848444130 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 11:59:10 +0200
Subject: [PATCH 142/159] Clean up & undo all cache side-effects on `setUp` and
 `tearDown` to avoid sharing state between  tests

---
 .../EssentialFeedCacheIntegrationTests.swift  | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index 3cd556c..027fc4d 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -9,6 +9,16 @@ import XCTest
 import EssentialFeed
 
 final class EssentialFeedCacheIntegrationTests: XCTestCase {
+    
+    override func setUp() {
+        super.setUp()
+        setupEmptyStoreState()
+    }
+    
+    override func tearDown() {
+        super.tearDown()
+        undoStoreSideEffects()
+    }
    
     func test_load_deliversNoItemsOnEmptyCache() {
         let sut = makeSUT()
@@ -52,4 +62,16 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
     private func cachesDirectory() -> URL {
         return FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!
     }
+    
+    private func setupEmptyStoreState() {
+        deleteStoreArtifacts()
+    }
+    
+    private func undoStoreSideEffects() {
+        deleteStoreArtifacts()
+    }
+    
+    private func deleteStoreArtifacts() {
+        try? FileManager.default.removeItem(at: testSpecificStoreURL())
+    }
 }

From 5b7eca9ac5d2bba019e2f717511f0a27b6f91747 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:00:10 +0200
Subject: [PATCH 143/159] `LocalFeedLoader` in integration with
 `CoreDataFeedStore`delivers items saved on separated instances proving we
 correctly persist the data models to disk

---
 .../EssentialFeedCacheIntegrationTests.swift  | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index 027fc4d..0d94428 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -37,6 +37,31 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         wait(for: [exp], timeout: 1.0)
     }
     
+    func test_load_deliversItemsSavedOnASeparatedInstance() {
+        let sutToPerformSave = makeSUT()
+        let sutToPerformLoad = makeSUT()
+        let feed = uniqueImageFeed().models
+        
+        let saveExp = expectation(description: "Wait for save completion")
+        sutToPerformSave.save(feed) { saveError in
+            XCTAssertNil(saveError, "Expected to save feed succesfully")
+            saveExp.fulfill()
+        }
+        wait(for: [saveExp], timeout: 1.0)
+        
+        let loadExp = expectation(description: "Wait for load completion")
+        sutToPerformLoad.load { result in
+            loadExp.fulfill()
+            switch result {
+            case let .success(imageFeed):
+                XCTAssertEqual(imageFeed, feed, "Expected saved feed")
+            case let .failure(error):
+                XCTFail("Expected successful feed result, got \(error) instead")
+            }
+        }
+        wait(for: [loadExp], timeout: 1.0)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(file: StaticString = #file, line: UInt = #line) -> LocalFeedLoader {

From 225e17791af41281176f03bf386ab86a7bf1fc9f Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:05:09 +0200
Subject: [PATCH 144/159] Extract duplicate cache load expectations into a
 shared helper method

---
 .../EssentialFeedCacheIntegrationTests.swift  | 56 +++++++++++--------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index 0d94428..f4a3d83 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -22,19 +22,7 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
    
     func test_load_deliversNoItemsOnEmptyCache() {
         let sut = makeSUT()
-        
-        let exp = expectation(description: "Wait for load completion")
-        sut.load { result in
-            exp.fulfill()
-            switch result {
-            case let .success(imageFeed):
-                XCTAssertEqual(imageFeed, [], "Expected empty feed")
-            case let .failure(error):
-                XCTFail("Expected successful feed result, got \(error) instead")
-            }
-        }
-        
-        wait(for: [exp], timeout: 1.0)
+        expect(sut, toLoad: [])
     }
     
     func test_load_deliversItemsSavedOnASeparatedInstance() {
@@ -49,17 +37,7 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         }
         wait(for: [saveExp], timeout: 1.0)
         
-        let loadExp = expectation(description: "Wait for load completion")
-        sutToPerformLoad.load { result in
-            loadExp.fulfill()
-            switch result {
-            case let .success(imageFeed):
-                XCTAssertEqual(imageFeed, feed, "Expected saved feed")
-            case let .failure(error):
-                XCTFail("Expected successful feed result, got \(error) instead")
-            }
-        }
-        wait(for: [loadExp], timeout: 1.0)
+        expect(sutToPerformLoad, toLoad: feed)
     }
     
     // MARK: - Helpers
@@ -80,6 +58,36 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         return sut
     }
     
+    private func expect(
+        _ sut: LocalFeedLoader,
+        toLoad expectedImageFeed: [FeedImage],
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let exp = expectation(description: "Wait for load completion")
+        sut.load { result in
+            exp.fulfill()
+            switch result {
+            case let .success(imageFeed):
+                XCTAssertEqual(
+                    imageFeed,
+                    expectedImageFeed,
+                    "Expected empty feed",
+                    file: file,
+                    line: line
+                )
+            case let .failure(error):
+                XCTFail(
+                    "Expected successful feed result, got \(error) instead",
+                    file: file,
+                    line: line
+                )
+            }
+        }
+        
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     private func testSpecificStoreURL() -> URL {
         return cachesDirectory().appendingPathComponent("\(type(of: self)).store")
     }

From ce790532cbc6a4b9b97e8390662a49fb85461b1a Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:10:41 +0200
Subject: [PATCH 145/159] `LocalFeedLoader` in integration with the
 `CoreDataFeedStore` overrides items saved by separated instances, proving we
 correctly manage the data models on disk;

---
 .../EssentialFeedCacheIntegrationTests.swift  | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index f4a3d83..9cdca4b 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -40,6 +40,30 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         expect(sutToPerformLoad, toLoad: feed)
     }
     
+    func test_save_overridesItemsSavedOnASeparatedInstance() {
+        let sutToPerformFirstSave = makeSUT()
+        let sutToPerformLastSave = makeSUT()
+        let sutToPerformLoad = makeSUT()
+        let firstFeed = uniqueImageFeed().models
+        let latestFeed = uniqueImageFeed().models
+        
+        let saveExp1 = expectation(description: "Wait for save completion")
+        sutToPerformFirstSave.save(firstFeed) { saveError in
+            XCTAssertNil(saveError, "Expected to save feed succesfully")
+            saveExp1.fulfill()
+        }
+        wait(for: [saveExp1], timeout: 1.0)
+        
+        let saveExp2 = expectation(description: "Wait for save completion")
+        sutToPerformLastSave.save(latestFeed) { saveError in
+            XCTAssertNil(saveError, "Expected to save feed successfully")
+            saveExp2.fulfill()
+        }
+        wait(for: [saveExp2], timeout: 1.0)
+        
+        expect(sutToPerformLoad, toLoad: latestFeed)
+    }
+    
     // MARK: - Helpers
     
     private func makeSUT(file: StaticString = #file, line: UInt = #line) -> LocalFeedLoader {

From 0eefecc53db604b50bd80ccc4c2ca13290367d49 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:15:10 +0200
Subject: [PATCH 146/159] Extract duplicated save operation into a shared
 helper method

---
 .../EssentialFeedCacheIntegrationTests.swift  | 37 +++++++++----------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index 9cdca4b..18e2f2c 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -30,12 +30,7 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         let sutToPerformLoad = makeSUT()
         let feed = uniqueImageFeed().models
         
-        let saveExp = expectation(description: "Wait for save completion")
-        sutToPerformSave.save(feed) { saveError in
-            XCTAssertNil(saveError, "Expected to save feed succesfully")
-            saveExp.fulfill()
-        }
-        wait(for: [saveExp], timeout: 1.0)
+        save(feed, with: sutToPerformSave)
         
         expect(sutToPerformLoad, toLoad: feed)
     }
@@ -47,19 +42,8 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         let firstFeed = uniqueImageFeed().models
         let latestFeed = uniqueImageFeed().models
         
-        let saveExp1 = expectation(description: "Wait for save completion")
-        sutToPerformFirstSave.save(firstFeed) { saveError in
-            XCTAssertNil(saveError, "Expected to save feed succesfully")
-            saveExp1.fulfill()
-        }
-        wait(for: [saveExp1], timeout: 1.0)
-        
-        let saveExp2 = expectation(description: "Wait for save completion")
-        sutToPerformLastSave.save(latestFeed) { saveError in
-            XCTAssertNil(saveError, "Expected to save feed successfully")
-            saveExp2.fulfill()
-        }
-        wait(for: [saveExp2], timeout: 1.0)
+        save(firstFeed, with: sutToPerformFirstSave)
+        save(latestFeed, with: sutToPerformLastSave)
         
         expect(sutToPerformLoad, toLoad: latestFeed)
     }
@@ -112,6 +96,21 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         wait(for: [exp], timeout: 1.0)
     }
     
+    
+    private func save(
+        _ feed: [FeedImage],
+        with sut: LocalFeedLoader,
+        file: StaticString = #file,
+        line: UInt = #line
+    ) {
+        let exp = expectation(description: "Wait for save completion")
+        sut.save(feed) { error in
+                XCTAssertNil(error, "Unexpected error: \(String(describing: error))", file: file, line: line)
+            exp.fulfill()
+        }
+        wait(for: [exp], timeout: 1.0)
+    }
+    
     private func testSpecificStoreURL() -> URL {
         return cachesDirectory().appendingPathComponent("\(type(of: self)).store")
     }

From 11c5c47a95d0540b54c552077f5d3347e8bacfb7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:21:23 +0200
Subject: [PATCH 147/159] Delete the `CodableFeedStore` in favor of the
 `CoreDataFeedStore`(we just need one in this project). If needed, of course,
 we can revert this commit and restore the `Codable` implementation

---
 .../EssentialFeed.xcodeproj/project.pbxproj   |   8 -
 .../Infrastructure/CodableFeedStore.swift     |  97 ----------
 .../Feed Cache/CodableFeedStoreTests.swift    | 176 ------------------
 3 files changed, 281 deletions(-)
 delete mode 100644 EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CodableFeedStore.swift
 delete mode 100644 EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift

diff --git a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
index 90edca3..0be8578 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
+++ b/EssentialFeed/EssentialFeed.xcodeproj/project.pbxproj
@@ -19,8 +19,6 @@
 		407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */; };
 		407F4FA72D9FDB810070F56E /* FeedCacheTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */; };
 		407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */; };
-		407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */; };
-		407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FB02DA022C00070F56E /* CodableFeedStore.swift */; };
 		407F4FCA2DA402D80070F56E /* FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */; };
 		407F4FCC2DA403330070F56E /* XCTestCase+FeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */; };
 		407F4FD12DA530810070F56E /* CoreDataFeedStoreSpecs.swift in Sources */ = {isa = PBXBuildFile; fileRef = 407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */; };
@@ -74,8 +72,6 @@
 		407F4FA42D9FD7EF0070F56E /* ValidateFeedCacheUseCaseTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ValidateFeedCacheUseCaseTests.swift; sourceTree = "<group>"; };
 		407F4FA62D9FDB780070F56E /* FeedCacheTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCacheTestHelpers.swift; sourceTree = "<group>"; };
 		407F4FAC2D9FEBC50070F56E /* FeedCachePolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedCachePolicy.swift; sourceTree = "<group>"; };
-		407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStoreTests.swift; sourceTree = "<group>"; };
-		407F4FB02DA022C00070F56E /* CodableFeedStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodableFeedStore.swift; sourceTree = "<group>"; };
 		407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedStoreSpecs.swift; sourceTree = "<group>"; };
 		407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "XCTestCase+FeedStoreSpecs.swift"; sourceTree = "<group>"; };
 		407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreDataFeedStoreSpecs.swift; sourceTree = "<group>"; };
@@ -220,7 +216,6 @@
 			isa = PBXGroup;
 			children = (
 				40412A1B2DA67135004677C4 /* CoreData */,
-				407F4FB02DA022C00070F56E /* CodableFeedStore.swift */,
 			);
 			path = Infrastructure;
 			sourceTree = "<group>";
@@ -240,7 +235,6 @@
 		40B975392D9E7AD3009652B5 /* Feed Cache */ = {
 			isa = PBXGroup;
 			children = (
-				407F4FAE2D9FFF640070F56E /* CodableFeedStoreTests.swift */,
 				407F4FD02DA5307B0070F56E /* CoreDataFeedStoreSpecs.swift */,
 				407F4FCB2DA403260070F56E /* XCTestCase+FeedStoreSpecs.swift */,
 				407F4FC92DA402D30070F56E /* FeedStoreSpecs.swift */,
@@ -463,7 +457,6 @@
 				40B975492D9EA7A2009652B5 /* LocalFeedImage.swift in Sources */,
 				407F4FAD2D9FEBC50070F56E /* FeedCachePolicy.swift in Sources */,
 				40B975452D9EA01D009652B5 /* FeedStore.swift in Sources */,
-				407F4FB22DA022FF0070F56E /* CodableFeedStore.swift in Sources */,
 				407F4FD32DA531050070F56E /* CoreDataFeedStore.swift in Sources */,
 				40412A1F2DA67227004677C4 /* ManagedCache.swift in Sources */,
 				40B975432D9E9FC4009652B5 /* LocalFeedLoader.swift in Sources */,
@@ -475,7 +468,6 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				407F4FAF2D9FFF680070F56E /* CodableFeedStoreTests.swift in Sources */,
 				407F4FA52D9FD7F90070F56E /* ValidateFeedCacheUseCaseTests.swift in Sources */,
 				40B9754E2D9EC15A009652B5 /* FeedStoreSpy.swift in Sources */,
 				407F4FD12DA530810070F56E /* CoreDataFeedStoreSpecs.swift in Sources */,
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CodableFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CodableFeedStore.swift
deleted file mode 100644
index d939603..0000000
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CodableFeedStore.swift	
+++ /dev/null
@@ -1,97 +0,0 @@
-//
-//  CodableFeedStore.swift
-//  EssentialFeed
-//
-//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
-//
-
-
-import Foundation
-
-public class CodableFeedStore: FeedStore {
-    private struct Cache: Codable {
-        let feed: [CodableFeedImage]
-        let timestamp: Date
-        
-        var localFeed: [LocalFeedImage] {
-            feed.map {
-                LocalFeedImage(
-                    id: $0.id,
-                    description: $0.description,
-                    location: $0.location,
-                    url: $0.url
-                )
-            }
-        }
-    }
-    
-    private struct CodableFeedImage: Codable {
-        fileprivate let id: UUID
-        fileprivate let description: String?
-        fileprivate let location: String?
-        fileprivate let url: URL
-        
-        init(_ image: LocalFeedImage) {
-            id = image.id
-            description = image.description
-            location = image.location
-            url = image.url
-        }
-    }
-    
-    private let storeURL: URL
-    private let queue = DispatchQueue(
-        label: "\(CodableFeedStore.self)-queue",
-        qos: .userInitiated,
-        attributes: .concurrent
-    )
-    
-    public init(storeURL: URL) {
-        self.storeURL = storeURL
-    }
-    
-    public func retrieve(completion: @escaping RetrievalCompletion) {
-        queue.async { [storeURL] in
-            guard let data = try? Data(contentsOf: storeURL) else {
-                return completion(.empty)
-            }
-            
-            do {
-                let decoder = JSONDecoder()
-                let cache = try decoder.decode(Cache.self, from: data)
-                completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
-            } catch {
-                completion(.failure(error))
-            }
-        }
-    }
-    
-    public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
-        queue.async(flags: .barrier) { [storeURL] in
-            do {
-                let encoder = JSONEncoder()
-                let cache = Cache(feed: feed.map(CodableFeedImage.init), timestamp: timestamp)
-                let encoded = try encoder.encode(cache)
-                try encoded.write(to: storeURL)
-                completion(nil)
-            } catch {
-                completion(error)
-            }
-        }
-    }
-    
-    public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
-        queue.async(flags: .barrier) { [storeURL] in
-            guard FileManager.default.fileExists(atPath: storeURL.path) else {
-                return completion(nil)
-            }
-            
-            do {
-                try FileManager.default.removeItem(at: storeURL)
-                completion(nil)
-            } catch {
-                completion(error)
-            }
-        }
-    }
-}
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift
deleted file mode 100644
index dc4237e..0000000
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CodableFeedStoreTests.swift	
+++ /dev/null
@@ -1,176 +0,0 @@
-//
-//  CodableFeedStoreTests.swift
-//  EssentialFeed
-//
-//  Created by Cristian Felipe Patiño Rojas on 4/4/25.
-//
-
-import XCTest
-import EssentialFeed
-
-class CodableFeedStoreTests: XCTestCase, FeedStoreSpecs {
-    
-    override func setUp() {
-        super.setUp()
-        setupEmptyStoreState()
-    }
-    
-    override func tearDown() {
-        super.setUp()
-        undoStoreSideEfects()
-    }
-    
-    func test_retrieve_deliversEmptyOnEmptyCache() {
-        let sut = makeSUT()
-        assertThatStoreSideEffectsRunSerially(on: sut)
-    }
-    
-    func test_retrieve_hasNoSideEffectsOnEmptyCache() {
-        let sut = makeSUT()
-        assertThatRetrieveHasNoSideEffectsOnEmptyCache(on: sut)
-    }
-    
-    func test_retrieve_deliversFoundValuesOnNonEmptyCache() {
-        let sut = makeSUT()
-        assertThatRetrieveDeliversFoundValuesOnNonEmptyCache(on: sut)
-    }
-    
-    func test_retrieve_hasNoSideEffectsOnNonEmptyCache() {
-        let sut = makeSUT()
-        assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(on: sut)
-    }
-    
-    func test_insert_deliversNoErrorOnEmptyCache() {
-        let sut = makeSUT()
-        assertThatInsertDeliversNoErrorOnEmptyCache(on: sut)
-    }
-    
-    func test_insert_deliversNoErrorOnNonEmptyCache() {
-        let sut = makeSUT()
-        assertThatInsertDeliversNoErrorOnNonEmptyCache(on: sut)
-    }
-    
-    func test_insert_overridesPreviouslyInsertedCacheValues() {
-        let sut = makeSUT()
-        
-        assertThatInsertOverridesPreviouslyInsertedCacheValues(on: sut)
-    }
-    
-    func test_delete_hasNoSideEffectsOnEmptyCache() {
-        let sut = makeSUT()
-        assertThatDeleteHasNoSideEffectOnEmptyCache(on: sut)
-    }
-    
-    func test_delete_emptiesPreviouslyInsertedCache() {
-        let sut = makeSUT()
-        assertThatDeleteEmptiesPreviouslyInsertedCache(on: sut)
-    }
-    
-    func test_storeSideEffects_runSerially() {
-        let sut = makeSUT()
-        assertThatStoreSideEffectsRunSerially(on: sut)
-    }
-    
-    func test_delete_deliversNoErrorOnEmptyCache() {
-        let sut = makeSUT()
-        assertThatDeleteDeliversNoErrorOnEmptyCache(on: sut)
-        
-    }
-    
-    func test_delete_deliversNoErrorOnNonEmptyCache() {
-        let sut = makeSUT()
-        assertThatDeleteDeliversNoErrorOnNonEmptyCache(on: sut)
-    }
-    
-    // MARK: - Helpers
-    private func makeSUT(
-        storeURL: URL? = nil,
-        file: StaticString = #file,
-        line: UInt = #line
-    ) -> FeedStore {
-        let sut = CodableFeedStore(storeURL: storeURL ?? testSpecificStoreURL())
-        trackForMemoryLeaks(sut, file: file, line: line)
-        return sut
-    }
-    
-    private func systemMaskCachesDirectory() -> URL {
-        FileManager.default.urls(for: .cachesDirectory, in: .systemDomainMask).first!
-    }
-    
-    private func testSpecificStoreURL() -> URL {
-        FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.appendingPathComponent("\(type(of: self)).store")
-    }
-    
-    private func setupEmptyStoreState() {
-        deleteStoreArtifacts()
-    }
-    
-    private func undoStoreSideEfects() {
-        deleteStoreArtifacts()
-    }
-    
-    private func  deleteStoreArtifacts() {
-        try? FileManager.default.removeItem(at: testSpecificStoreURL())
-    }
-}
-
-extension CodableFeedStoreTests: FailableRetrieveFeedStoreSpecs {
-    func test_retrieve_deliversFailureOnRetrievalError() {
-        let storeURL = testSpecificStoreURL()
-        let sut = makeSUT(storeURL: storeURL)
-        
-        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
-        
-        expect(sut, toRetrieve: .failure(anyNSError()))
-    }
-    
-    func test_retrieve_hasNoSideEffectsOnFailure() {
-        let storeURL = testSpecificStoreURL()
-        let sut = makeSUT(storeURL: storeURL)
-        
-        try! "invalid data".write(to: storeURL, atomically: false, encoding: .utf8)
-        
-        expect(sut, toRetrieveTwice: .failure(anyNSError()))
-    }
-}
-
-extension CodableFeedStoreTests: FailableInsertFeedStoreSpecs {
-    func test_insert_deliversErrorOnInsertionError() {
-        let invalidStoreURL = URL(string: "invalid://store-url")
-        let sut = makeSUT(storeURL: invalidStoreURL)
-        let feed = uniqueImageFeed().local
-        let timestamp = Date()
-        let insertionError = insert((feed, timestamp), to: sut)
-        XCTAssertNotNil(insertionError, "Expected cache insertion to fail with an error")
-    }
-    
-    func test_insert_hasNoSideEffectsOnInsertionError() {
-        let invalidStoreURL = URL(string: "invalid://store-url")
-        let sut = makeSUT(storeURL: invalidStoreURL)
-        let feed = uniqueImageFeed().local
-        let timestamp = Date()
-        
-        insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieve: .empty)
-    }
-}
-
-
-extension CodableFeedStoreTests: FailableDeleteFeedStoreSpecs {
-    func test_delete_deliversErrorOnDeletionError() {
-        let noDeletePermissionURL = systemMaskCachesDirectory()
-        let sut = makeSUT(storeURL: noDeletePermissionURL)
-        
-        let deletionError = deleteCache(from: sut)
-        
-        XCTAssertNotNil(deletionError, "Expect cache deletion to fail")
-    }
-    
-    func test_delete_hasNoSideEffectsOnDeletionError() {
-        let noDeletePermissionURL = systemMaskCachesDirectory()
-        let sut = makeSUT(storeURL: noDeletePermissionURL)
-        
-        deleteCache(from: sut)
-        expect(sut, toRetrieve: .empty)
-    }
-}

From c11b385da268e56b7b08028ddb984051f5070ce6 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:25:30 +0200
Subject: [PATCH 148/159] Include `EssentialFeedCacheIntegrationTests`test
 target in the CI scheme to guarantee we build and run all cahce integration
 tests as part of the continuos integration pipeline.

---
 EssentialFeed/CI.xctestplan                   | 38 +++++++++++++++++++
 .../xcshareddata/xcschemes/CI.xcscheme        |  9 ++++-
 2 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 EssentialFeed/CI.xctestplan

diff --git a/EssentialFeed/CI.xctestplan b/EssentialFeed/CI.xctestplan
new file mode 100644
index 0000000..a769de9
--- /dev/null
+++ b/EssentialFeed/CI.xctestplan
@@ -0,0 +1,38 @@
+{
+  "configurations" : [
+    {
+      "id" : "FB6DC599-8749-4C8A-B598-7DA402070AD5",
+      "name" : "Test Scheme Action",
+      "options" : {
+
+      }
+    }
+  ],
+  "defaultOptions" : {
+    "testExecutionOrdering" : "random"
+  },
+  "testTargets" : [
+    {
+      "target" : {
+        "containerPath" : "container:EssentialFeed.xcodeproj",
+        "identifier" : "080EDEF921B6DA7E00813479",
+        "name" : "EssentialFeedTests"
+      }
+    },
+    {
+      "target" : {
+        "containerPath" : "container:EssentialFeed.xcodeproj",
+        "identifier" : "40B002442CF9E9DB0058D3E0",
+        "name" : "EssentialFeedAPIEndToEndTests"
+      }
+    },
+    {
+      "target" : {
+        "containerPath" : "container:EssentialFeed.xcodeproj",
+        "identifier" : "40412A492DA67465004677C4",
+        "name" : "EssentialFeedCacheIntegrationTests"
+      }
+    }
+  ],
+  "version" : 1
+}
diff --git a/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/CI.xcscheme b/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/CI.xcscheme
index 2f55a46..5e69754 100644
--- a/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/CI.xcscheme
+++ b/EssentialFeed/EssentialFeed.xcodeproj/xcshareddata/xcschemes/CI.xcscheme
@@ -27,8 +27,13 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      shouldUseLaunchSchemeArgsEnv = "YES"
-      shouldAutocreateTestPlan = "YES">
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <TestPlans>
+         <TestPlanReference
+            reference = "container:CI.xctestplan"
+            default = "YES">
+         </TestPlanReference>
+      </TestPlans>
       <Testables>
          <TestableReference
             skipped = "NO">

From 9b6a4af5e4dabde7d99bf6072503f748ac608a84 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:32:06 +0200
Subject: [PATCH 149/159] Remove redunant `internal` access control
 declarations

---
 .../EssentialFeed/Feed Cache/FeedCachePolicy.swift     |  2 +-
 .../EssentialFeed/FeedApi/FeedItemsMapper.swift        |  4 ++--
 .../EssentialFeed/FeedApi/RemoteFeedItem.swift         | 10 +++++-----
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift
index 4b5450e..73dd51d 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedCachePolicy.swift	
@@ -7,7 +7,7 @@
 
 import Foundation
 
-internal final class FeedCachePolicy {
+final class FeedCachePolicy {
     private static let calendar = Calendar(identifier: .gregorian)
     private static var maxCacheAgeInDays: Int { return 7 }
     private init() {}
diff --git a/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift b/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
index 71a6644..5ddec9c 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/FeedItemsMapper.swift
@@ -8,7 +8,7 @@ import Foundation
 
 
 
-internal enum FeedItemsMapper {
+enum FeedItemsMapper {
     
     struct Root: Decodable {
         let items: [RemoteFeedItem]
@@ -17,7 +17,7 @@ internal enum FeedItemsMapper {
     private static let jsonDecoder = JSONDecoder()
     private static let OK_200 = 200
     
-    internal static func map(_ data: Data, from response: HTTPURLResponse) throws -> [RemoteFeedItem] {
+    static func map(_ data: Data, from response: HTTPURLResponse) throws -> [RemoteFeedItem] {
         guard
             response.statusCode == OK_200,
             let root = try? jsonDecoder.decode(Root.self, from: data) else {
diff --git a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift
index fff12ee..6589a30 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedItem.swift
@@ -6,9 +6,9 @@
 //
 import Foundation
 
-internal struct RemoteFeedItem: Decodable {
-    internal let id: UUID
-    internal let description: String?
-    internal let location: String?
-    internal let image: URL
+struct RemoteFeedItem: Decodable {
+    let id: UUID
+    let description: String?
+    let location: String?
+    let image: URL
 }

From e12c8acb4bc68c014a327c65807fb2abb2aecb59 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:35:16 +0200
Subject: [PATCH 150/159] Replace custom `LoadFeedResult` enum with standard
 swift result type

---
 EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift
index acd3d92..861aa06 100644
--- a/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift	
@@ -4,10 +4,7 @@
 
 import Foundation
 
-public enum LoadFeedResult {
-	case success([FeedImage])
-	case failure(Error)
-}
+public typealias LoadFeedResult = Result<[FeedImage], Error>
 
 public protocol FeedLoader {
 	func load(completion: @escaping (LoadFeedResult) -> Void)

From b384d3e6a4c4f42ab46f3c7083327324005749f4 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:37:33 +0200
Subject: [PATCH 151/159] Nest `LocalFeedResult` into the `FeedLoader` protocol
 as `FeedLoader.Result`sinte they're closely related

---
 EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift  | 2 +-
 EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift     | 4 ++--
 EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift    | 2 +-
 .../EssentialFeedAPIEndToEndTests.swift                       | 4 ++--
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 191acf1..8739b19 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -18,7 +18,7 @@ public final class LocalFeedLoader: FeedLoader {
 }
    
 extension LocalFeedLoader {
-    public typealias LoadResult = LoadFeedResult
+    public typealias LoadResult = FeedLoader.Result
     public func load(completion: @escaping (LoadResult) -> Void) {
         store.retrieve { [weak self] result in
             guard let self else { return }
diff --git a/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift
index 861aa06..c447b7e 100644
--- a/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Feature/FeedLoader.swift	
@@ -4,8 +4,8 @@
 
 import Foundation
 
-public typealias LoadFeedResult = Result<[FeedImage], Error>
 
 public protocol FeedLoader {
-	func load(completion: @escaping (LoadFeedResult) -> Void)
+    typealias Result = Swift.Result<[FeedImage], Error>
+	func load(completion: @escaping (Result) -> Void)
 }
diff --git a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
index 5f2c838..2242520 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
@@ -16,7 +16,7 @@ public final class RemoteFeedLoader: FeedLoader {
         case invalidData
     }
    
-    public typealias Result = LoadFeedResult
+    public typealias Result = FeedLoader.Result
     
     public init(url: URL, client: HTTPClient) {
         self.url = url
diff --git a/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift b/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift
index be50db2..7d0402a 100644
--- a/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift
+++ b/EssentialFeed/EssentialFeedAPIEndToEndTests/EssentialFeedAPIEndToEndTests.swift
@@ -32,7 +32,7 @@ final class EssentialFeedAPIEndToEndTests: XCTestCase {
     func getFeedResult(
         file: StaticString = #file,
         line: UInt = #line
-    ) -> LoadFeedResult? {
+    ) -> FeedLoader.Result? {
         let testServerURL = URL(string: "https://essentialdeveloper.com/feed-case-study/test-api/feed")!
         let client = URLSessionHTTPClient()
         let loader = RemoteFeedLoader(
@@ -44,7 +44,7 @@ final class EssentialFeedAPIEndToEndTests: XCTestCase {
         
         let exp = expectation(description: "Wait for load completion")
         
-        var receivedResult: LoadFeedResult?
+        var receivedResult: FeedLoader.Result?
         
         loader.load { result in
             receivedResult = result

From 840aea89abcc22f94983fda8ec2ad4ff68772e97 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:41:35 +0200
Subject: [PATCH 152/159] Replace custom `HTTPClientResult` enum with a
 typealias over the standard `Swift.Result`

---
 EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift       | 7 ++-----
 EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift | 2 +-
 .../EssentialFeed/FeedApi/URLSessionHTTPClient.swift       | 4 ++--
 .../Feed Api/LoadFeedFromRemoteUseCaseTests.swift          | 6 +++---
 .../Feed Api/URLSessionHTTPClientTests.swift               | 6 +++---
 5 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift b/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift
index aa292c8..068e1c3 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/HTTPClient.swift
@@ -6,14 +6,11 @@
 //
 import Foundation
 
-public enum HTTPClientResult {
-    case success(Data, HTTPURLResponse)
-    case failure(Error)
-}
 
 public protocol HTTPClient {
     
+    typealias Result = Swift.Result<(Data, HTTPURLResponse), Error>
     /// The completion handler can be invoked in any thread.
     /// Clients are responsible to dispatch to appropiate threads, if needed.
-    func get(from url: URL, completion: @escaping (HTTPClientResult) -> Void)
+    func get(from url: URL, completion: @escaping (Result) -> Void)
 }
diff --git a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
index 2242520..b198fa6 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/RemoteFeedLoader.swift
@@ -27,7 +27,7 @@ public final class RemoteFeedLoader: FeedLoader {
         client.get(from: url) { [weak self] result in
             guard self != nil else { return }
             switch result {
-            case let .success(data, response):
+            case let .success((data, response)):
                 completion(Self.map(data, from: response))
             case .failure:
                 completion(.failure(Error.connectivity))
diff --git a/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift b/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift
index a8b0f85..e97d481 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift
@@ -15,12 +15,12 @@ public class URLSessionHTTPClient: HTTPClient {
     
     struct UnexpectedValuesRepresentation: Error {}
     
-    public func get(from url: URL, completion: @escaping (HTTPClientResult) -> Void) {
+    public func get(from url: URL, completion: @escaping (HTTPClient.Result) -> Void) {
         session.dataTask(with: url)  { data, response, error in
             if let error {
                 completion(.failure(error))
             } else if let data, let response = response as? HTTPURLResponse {
-                completion(.success(data, response))
+                completion(.success((data, response)))
             } else {
                 completion(.failure(UnexpectedValuesRepresentation()))
             }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift
index 03fa678..5cc37d1 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Api/LoadFeedFromRemoteUseCaseTests.swift	
@@ -174,9 +174,9 @@ class LoadFeedFromRemoteUseCaseTests: XCTestCase {
             messages.map(\.url)
         }
         
-        private var messages = [(url: URL, completion: (HTTPClientResult) -> Void)]()
+        private var messages = [(url: URL, completion: (HTTPClient.Result) -> Void)]()
         
-        func get(from url: URL, completion: @escaping (HTTPClientResult) -> Void) {
+        func get(from url: URL, completion: @escaping (HTTPClient.Result) -> Void) {
             messages.append((url, completion))
         }
         
@@ -192,7 +192,7 @@ class LoadFeedFromRemoteUseCaseTests: XCTestCase {
                 headerFields: nil
             )!
             
-            messages[index].completion(.success(data, response))
+            messages[index].completion(.success((data, response)))
         }
     }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift b/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift
index 6e36dba..f0c73ec 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Api/URLSessionHTTPClientTests.swift	
@@ -118,7 +118,7 @@ class URLSessionHTTPClientTests: XCTestCase {
         
         
         switch result {
-        case let .success(data, response):
+        case let .success((data, response)):
             return (data: data, response: response)
         default:
             XCTFail(
@@ -136,7 +136,7 @@ class URLSessionHTTPClientTests: XCTestCase {
         error: Error?,
         file: StaticString = #file,
         line: UInt = #line
-    ) -> HTTPClientResult {
+    ) -> HTTPClient.Result {
         let url = anyURL()
         let sut = makeSUT(file: file, line: line)
         URLProtocolStub.stub(
@@ -146,7 +146,7 @@ class URLSessionHTTPClientTests: XCTestCase {
         
         let exp = expectation(description: "Wait for completion")
         
-        var receivedResult: HTTPClientResult!
+        var receivedResult: HTTPClient.Result!
         
         sut.get(from: url) { result in
             receivedResult = result

From 45a738e673ce44a72455a4ee0b260ad7c7d16ac1 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:50:40 +0200
Subject: [PATCH 153/159] Replace custom `RetrieveCacheFeedResult`enum with a
 nest typealais over the standard `Swift.Result`(`FeedStore.RetrievalResult`)

---
 .../EssentialFeed/Feed Cache/FeedStore.swift  |  9 +++++---
 .../CoreData/CoreDataFeedStore.swift          |  4 ++--
 .../Feed Cache/LocalFeedLoader.swift          |  8 +++----
 .../Feed Cache/Helpers/FeedStoreSpy.swift     |  4 ++--
 .../XCTestCase+FeedStoreSpecs.swift           | 22 +++++++++----------
 5 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 26b34a8..03b80a3 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -7,16 +7,19 @@
 
 import Foundation
 
-public enum RetrieveCachedFeedResult {
+
+public enum CacheFeed {
     case empty
     case found(feed: [LocalFeedImage], timestamp: Date)
-    case failure(Error)
 }
 
 public protocol FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     typealias InsertionCompletion = (Error?) -> Void
-    typealias RetrievalCompletion = (RetrieveCachedFeedResult) -> Void
+    
+    
+    typealias RetrievalResult = Result<CacheFeed, Error>
+    typealias RetrievalCompletion = (RetrievalResult) -> Void
     
     /// The completion handler can be invoked in any thread.
     /// Clients are responsible to dispatch to appropiate threads, if needed.
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
index 0a73608..e2f080d 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
@@ -25,9 +25,9 @@ public final class CoreDataFeedStore: FeedStore {
             
             do {
                 if let cache = try ManagedCache.find(in: context) {
-                    completion(.found(feed: cache.localFeed, timestamp: cache.timestamp))
+                    completion(.success(.found(feed: cache.localFeed, timestamp: cache.timestamp)))
                 } else {
-                    completion(.empty)
+                    completion(.success(.empty))
                 }
             } catch {
                 completion(.failure(error))
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 8739b19..2a1c387 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -26,9 +26,9 @@ extension LocalFeedLoader {
             case let .failure(error):
                 completion(.failure(error))
                 
-            case let .found(feed, timestamp) where FeedCachePolicy.validate(timestamp, against: currentDate()):
+            case let .success(.found(feed, timestamp)) where FeedCachePolicy.validate(timestamp, against: currentDate()):
                 completion(.success(feed.toModels()))
-            case .found, .empty:
+            case .success:
                 completion(.success([]))
             }
         }
@@ -40,11 +40,11 @@ extension LocalFeedLoader {
         store.retrieve { [weak self] result in
             guard let self else { return }
             switch result {
-            case let .found(_, timestamp) where !FeedCachePolicy.validate(timestamp, against: currentDate()):
+            case let .success(.found(_, timestamp)) where !FeedCachePolicy.validate(timestamp, against: currentDate()):
                 self.store.deleteCachedFeed { _ in }
             case .failure:
                 self.store.deleteCachedFeed { _ in }
-            case .empty, .found: break
+            case .success: break
             }
         }
     }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index d142bce..f916ccc 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -59,10 +59,10 @@ class FeedStoreSpy: FeedStore {
     }
     
     func completeRetrievalWithEmptyCache(at index: Int = 0) {
-        retrievalCompletions[index](.empty)
+        retrievalCompletions[index](.success(.empty))
     }
     
     func completeRetrieval(with feed: [LocalFeedImage], timestamp: Date, at index: Int = 0) {
-        retrievalCompletions[index](.found(feed: feed, timestamp: timestamp))
+        retrievalCompletions[index](.success(.found(feed: feed, timestamp: timestamp)))
     }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index ca96c0f..f714ea8 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -36,7 +36,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
     
     func expect(
         _ sut: FeedStore,
-        toRetrieve expectedResult: RetrieveCachedFeedResult,
+        toRetrieve expectedResult: FeedStore.RetrievalResult,
         file: StaticString = #file,
         line: UInt = #line
     ) {
@@ -45,9 +45,9 @@ extension FeedStoreSpecs where Self: XCTestCase {
         sut.retrieve { retrievedResult in
             exp.fulfill()
             switch (expectedResult, retrievedResult) {
-            case (.empty, .empty), (.failure, .failure):
+            case (.success(.empty), .success(.empty)), (.failure, .failure):
                 break
-            case let (.found(expectedFeed, expectedTimestmap), .found(retrievedFeed, retrievedTimestamp)):
+            case let (.success(.found(expectedFeed, expectedTimestmap)), .success(.found(retrievedFeed, retrievedTimestamp))):
                 XCTAssertEqual(expectedFeed, retrievedFeed, file: file, line: line)
                 XCTAssertEqual(expectedTimestmap, retrievedTimestamp, file: file, line: line)
             default:
@@ -59,7 +59,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
     
     func expect(
         _ sut: FeedStore,
-        toRetrieveTwice expectedResult: RetrieveCachedFeedResult,
+        toRetrieveTwice expectedResult: FeedStore.RetrievalResult,
         file: StaticString = #file,
         line: UInt = #line
     ) {
@@ -74,7 +74,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         file: StaticString = #file,
         line: UInt = #line
     ) {
-        expect(sut, toRetrieve: .empty)
+        expect(sut, toRetrieve: .success(.empty))
     }
     
     func assertThatRetrieveHasNoSideEffectsOnEmptyCache(
@@ -82,7 +82,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         file: StaticString = #file,
         line: UInt = #line
     ) {
-        expect(sut, toRetrieveTwice: .empty)
+        expect(sut, toRetrieveTwice: .success(.empty))
     }
     
     func assertThatRetrieveDeliversFoundValuesOnNonEmptyCache(
@@ -94,7 +94,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let timestamp = Date()
         
         insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieve: .found(feed: feed, timestamp: timestamp))
+        expect(sut, toRetrieve: .success(.found(feed: feed, timestamp: timestamp)))
     }
     
     func assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(
@@ -106,7 +106,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let timestamp = Date()
         
         insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieveTwice: .found(feed: feed, timestamp: timestamp))
+        expect(sut, toRetrieveTwice: .success(.found(feed: feed, timestamp: timestamp)))
     }
 }
 
@@ -138,7 +138,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let latestInsertionError = insert((latestFeed, latesTimestamp), to: sut)
         
         XCTAssertNil(latestInsertionError, "Expected to override cache succesfully")
-        expect(sut, toRetrieve: .found(feed: latestFeed, timestamp: latesTimestamp))
+        expect(sut, toRetrieve: .success(.found(feed: latestFeed, timestamp: latesTimestamp)))
     }
 }
 
@@ -164,7 +164,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let deletionError = deleteCache(from: sut)
         
         XCTAssertNil(deletionError, "Expected empty cache deletion to succeed")
-        expect(sut, toRetrieve: .empty)
+        expect(sut, toRetrieve: .success(.empty))
     }
     
     func assertThatDeleteEmptiesPreviouslyInsertedCache(
@@ -177,7 +177,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let deletionError = deleteCache(from: sut)
         
         XCTAssertNil(deletionError, "Expected non-empty cache deletion to succeed")
-        expect(sut, toRetrieve: .empty)
+        expect(sut, toRetrieve: .success(.empty))
     }
     
     func assertThatStoreSideEffectsRunSerially(

From b0fe572274f1b96c8f9f41796a62401fb305c4e7 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 12:58:40 +0200
Subject: [PATCH 154/159] Refactor `CacheFeed`type from `enum` to `tuple` since
 we can represent the absence of a value wiht an `Optional`

---
 .../EssentialFeed/Feed Cache/FeedStore.swift  |  7 ++----
 .../CoreData/CoreDataFeedStore.swift          |  4 ++--
 .../Feed Cache/LocalFeedLoader.swift          |  6 ++---
 .../Feed Cache/Helpers/FeedStoreSpy.swift     |  4 ++--
 .../XCTestCase+FeedStoreSpecs.swift           | 22 +++++++++----------
 5 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index 03b80a3..cea0c3e 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -8,17 +8,14 @@
 import Foundation
 
 
-public enum CacheFeed {
-    case empty
-    case found(feed: [LocalFeedImage], timestamp: Date)
-}
+public typealias CacheFeed = (feed: [LocalFeedImage], timestamp: Date)
 
 public protocol FeedStore {
     typealias DeletionCompletion = (Error?) -> Void
     typealias InsertionCompletion = (Error?) -> Void
     
     
-    typealias RetrievalResult = Result<CacheFeed, Error>
+    typealias RetrievalResult = Result<CacheFeed?, Error>
     typealias RetrievalCompletion = (RetrievalResult) -> Void
     
     /// The completion handler can be invoked in any thread.
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
index e2f080d..577cc22 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
@@ -25,9 +25,9 @@ public final class CoreDataFeedStore: FeedStore {
             
             do {
                 if let cache = try ManagedCache.find(in: context) {
-                    completion(.success(.found(feed: cache.localFeed, timestamp: cache.timestamp)))
+                    completion(.success(CacheFeed(feed: cache.localFeed, timestamp: cache.timestamp)))
                 } else {
-                    completion(.success(.empty))
+                    completion(.success(.none))
                 }
             } catch {
                 completion(.failure(error))
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index 2a1c387..efb9f57 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -26,8 +26,8 @@ extension LocalFeedLoader {
             case let .failure(error):
                 completion(.failure(error))
                 
-            case let .success(.found(feed, timestamp)) where FeedCachePolicy.validate(timestamp, against: currentDate()):
-                completion(.success(feed.toModels()))
+            case let .success(.some(cache)) where FeedCachePolicy.validate(cache.timestamp, against: currentDate()):
+                completion(.success(cache.feed.toModels()))
             case .success:
                 completion(.success([]))
             }
@@ -40,7 +40,7 @@ extension LocalFeedLoader {
         store.retrieve { [weak self] result in
             guard let self else { return }
             switch result {
-            case let .success(.found(_, timestamp)) where !FeedCachePolicy.validate(timestamp, against: currentDate()):
+            case let .success(.some(cache)) where !FeedCachePolicy.validate(cache.timestamp, against: currentDate()):
                 self.store.deleteCachedFeed { _ in }
             case .failure:
                 self.store.deleteCachedFeed { _ in }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index f916ccc..f602923 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -59,10 +59,10 @@ class FeedStoreSpy: FeedStore {
     }
     
     func completeRetrievalWithEmptyCache(at index: Int = 0) {
-        retrievalCompletions[index](.success(.empty))
+        retrievalCompletions[index](.success(.none))
     }
     
     func completeRetrieval(with feed: [LocalFeedImage], timestamp: Date, at index: Int = 0) {
-        retrievalCompletions[index](.success(.found(feed: feed, timestamp: timestamp)))
+        retrievalCompletions[index](.success(CacheFeed(feed: feed, timestamp: timestamp)))
     }
 }
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index f714ea8..a7c25af 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -45,11 +45,11 @@ extension FeedStoreSpecs where Self: XCTestCase {
         sut.retrieve { retrievedResult in
             exp.fulfill()
             switch (expectedResult, retrievedResult) {
-            case (.success(.empty), .success(.empty)), (.failure, .failure):
+            case (.success(.none), .success(.none)), (.failure, .failure):
                 break
-            case let (.success(.found(expectedFeed, expectedTimestmap)), .success(.found(retrievedFeed, retrievedTimestamp))):
-                XCTAssertEqual(expectedFeed, retrievedFeed, file: file, line: line)
-                XCTAssertEqual(expectedTimestmap, retrievedTimestamp, file: file, line: line)
+            case let (.success(.some(expectedCache)), .success(.some(retrievedCache))):
+                XCTAssertEqual(expectedCache.feed, retrievedCache.feed, file: file, line: line)
+                XCTAssertEqual(expectedCache.timestamp, expectedCache.timestamp, file: file, line: line)
             default:
                 XCTFail("Expected to retrieve \(expectedResult), but got \(retrievedResult)", file: file, line: line)
             }
@@ -74,7 +74,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         file: StaticString = #file,
         line: UInt = #line
     ) {
-        expect(sut, toRetrieve: .success(.empty))
+        expect(sut, toRetrieve: .success(.none))
     }
     
     func assertThatRetrieveHasNoSideEffectsOnEmptyCache(
@@ -82,7 +82,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         file: StaticString = #file,
         line: UInt = #line
     ) {
-        expect(sut, toRetrieveTwice: .success(.empty))
+        expect(sut, toRetrieveTwice: .success(.none))
     }
     
     func assertThatRetrieveDeliversFoundValuesOnNonEmptyCache(
@@ -94,7 +94,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let timestamp = Date()
         
         insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieve: .success(.found(feed: feed, timestamp: timestamp)))
+        expect(sut, toRetrieve: .success(CacheFeed(feed: feed, timestamp: timestamp)))
     }
     
     func assertThatRetrieveHasNoSideEffectsOnNonEmptyCache(
@@ -106,7 +106,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let timestamp = Date()
         
         insert((feed, timestamp), to: sut)
-        expect(sut, toRetrieveTwice: .success(.found(feed: feed, timestamp: timestamp)))
+        expect(sut, toRetrieveTwice: .success(CacheFeed(feed: feed, timestamp: timestamp)))
     }
 }
 
@@ -138,7 +138,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let latestInsertionError = insert((latestFeed, latesTimestamp), to: sut)
         
         XCTAssertNil(latestInsertionError, "Expected to override cache succesfully")
-        expect(sut, toRetrieve: .success(.found(feed: latestFeed, timestamp: latesTimestamp)))
+        expect(sut, toRetrieve: .success(CacheFeed (feed: latestFeed, timestamp: latesTimestamp)))
     }
 }
 
@@ -164,7 +164,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let deletionError = deleteCache(from: sut)
         
         XCTAssertNil(deletionError, "Expected empty cache deletion to succeed")
-        expect(sut, toRetrieve: .success(.empty))
+        expect(sut, toRetrieve: .success(.none))
     }
     
     func assertThatDeleteEmptiesPreviouslyInsertedCache(
@@ -177,7 +177,7 @@ extension FeedStoreSpecs where Self: XCTestCase {
         let deletionError = deleteCache(from: sut)
         
         XCTAssertNil(deletionError, "Expected non-empty cache deletion to succeed")
-        expect(sut, toRetrieve: .success(.empty))
+        expect(sut, toRetrieve: .success(.none))
     }
     
     func assertThatStoreSideEffectsRunSerially(

From 3391786467a04fe4b0390cb12bcfd675a0bb772c Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 13:03:16 +0200
Subject: [PATCH 155/159] Add typealiases for `FeedStore.DeletionResult` and
 `FeedStore.InsertionResult`

---
 EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index cea0c3e..a9142bc 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -11,9 +11,11 @@ import Foundation
 public typealias CacheFeed = (feed: [LocalFeedImage], timestamp: Date)
 
 public protocol FeedStore {
-    typealias DeletionCompletion = (Error?) -> Void
-    typealias InsertionCompletion = (Error?) -> Void
+    typealias DeletionResult = Error?
+    typealias DeletionCompletion = (DeletionResult) -> Void
     
+    typealias InsertionResult = Error?
+    typealias InsertionCompletion = (InsertionResult) -> Void
     
     typealias RetrievalResult = Result<CacheFeed?, Error>
     typealias RetrievalCompletion = (RetrievalResult) -> Void

From 97189d0a752e15a14702e923b8bc5012815fd36c Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 13:12:29 +0200
Subject: [PATCH 156/159] Replace occurencies of `Error?`for representing
 operation success/failure wiht `Result<Void, Error>`

---
 .../EssentialFeed/Feed Cache/FeedStore.swift     |  4 ++--
 .../CoreData/CoreDataFeedStore.swift             |  8 ++++----
 .../Feed Cache/LocalFeedLoader.swift             | 11 ++++++-----
 .../EssentialFeedCacheIntegrationTests.swift     |  6 +++++-
 .../Feed Cache/CacheFeedUseCaseTests.swift       |  8 ++++++--
 .../Feed Cache/Helpers/FeedStoreSpy.swift        |  8 ++++----
 .../Feed Cache/XCTestCase+FeedStoreSpecs.swift   | 16 ++++++++++++----
 7 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift
index a9142bc..0c78bec 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/FeedStore.swift	
@@ -11,10 +11,10 @@ import Foundation
 public typealias CacheFeed = (feed: [LocalFeedImage], timestamp: Date)
 
 public protocol FeedStore {
-    typealias DeletionResult = Error?
+    typealias DeletionResult = Result<Void, Error>
     typealias DeletionCompletion = (DeletionResult) -> Void
     
-    typealias InsertionResult = Error?
+    typealias InsertionResult = Result<Void, Error>
     typealias InsertionCompletion = (InsertionResult) -> Void
     
     typealias RetrievalResult = Result<CacheFeed?, Error>
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
index 577cc22..6a9261c 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
@@ -45,9 +45,9 @@ public final class CoreDataFeedStore: FeedStore {
                     in: context
                 )
                 try context.save()
-                completion(nil)
+                completion(.success(()))
             } catch {
-                completion(error)
+                completion(.failure(error))
             }
         }
         
@@ -60,9 +60,9 @@ public final class CoreDataFeedStore: FeedStore {
                 try ManagedCache.find(in: context)
                     .map(context.delete)
                     .map(context.save)
-                completion(nil)
+                completion(.success(()))
             } catch {
-                completion(error)
+                completion(.failure(error))
             }
         }
     }
diff --git a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift
index efb9f57..ba75315 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/LocalFeedLoader.swift	
@@ -51,14 +51,15 @@ extension LocalFeedLoader {
 }
 
 extension LocalFeedLoader {
-    public typealias SaveResult = Error?
+    public typealias SaveResult = Result<Void, Error>
     public func save(_ feed: [FeedImage], completion: @escaping (SaveResult) -> Void) {
-        store.deleteCachedFeed { [weak self] error in
+        store.deleteCachedFeed { [weak self] deletionResult in
             guard let self else { return }
-            if let cacheDeletionError = error {
-                completion(cacheDeletionError)
-            } else {
+            switch deletionResult {
+            case .success:
                 self.cache(feed, with: completion)
+            case let .failure(error):
+                completion(.failure(error))
             }
         }
     }
diff --git a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
index 18e2f2c..29541f3 100644
--- a/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
+++ b/EssentialFeed/EssentialFeedCacheIntegrationTests/EssentialFeedCacheIntegrationTests.swift
@@ -104,8 +104,12 @@ final class EssentialFeedCacheIntegrationTests: XCTestCase {
         line: UInt = #line
     ) {
         let exp = expectation(description: "Wait for save completion")
-        sut.save(feed) { error in
+        sut.save(feed) { result in
+            switch result {
+            case let .failure(error):
                 XCTAssertNil(error, "Unexpected error: \(String(describing: error))", file: file, line: line)
+            default: break
+            }
             exp.fulfill()
         }
         wait(for: [exp], timeout: 1.0)
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift
index 1319e81..3e15850 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/CacheFeedUseCaseTests.swift	
@@ -111,9 +111,13 @@ class CacheFeedUseCaseTests: XCTestCase {
     ) {
         let exp = expectation(description: "Wait for save completion")
         var receivedError: Error?
-        sut.save(uniqueImageFeed().models) { error in
-            receivedError = error
+        sut.save(uniqueImageFeed().models) { result in
             exp.fulfill()
+            switch result {
+            case let .failure(error):
+                receivedError = error
+            default: break
+            }
         }
         
         action()
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift
index f602923..083ce85 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/Helpers/FeedStoreSpy.swift	
@@ -28,11 +28,11 @@ class FeedStoreSpy: FeedStore {
     }
     
     func completeDeletion(with error: Error, at index: Int = 0) {
-        deletionCompletions[index](error)
+        deletionCompletions[index](.failure(error))
     }
     
     func completeDeletionSuccesfully(at index: Int = 0) {
-        deletionCompletions[index](nil)
+        deletionCompletions[index](.success(()))
     }
     
     
@@ -42,11 +42,11 @@ class FeedStoreSpy: FeedStore {
     }
     
     func completeInsertion(with error: Error, at index: Int = 0) {
-        insertionCompletions[index](error)
+        insertionCompletions[index](.failure(error))
     }
     
     func completeInsertionSuccesfully(at index: Int = 0) {
-        insertionCompletions[index](nil)
+        insertionCompletions[index](.success(()))
     }
     
     func retrieve(completion: @escaping RetrievalCompletion) {
diff --git a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift
index a7c25af..3f59ed4 100644
--- a/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
+++ b/EssentialFeed/EssentialFeedTests/Feed Cache/XCTestCase+FeedStoreSpecs.swift	
@@ -12,8 +12,12 @@ extension FeedStoreSpecs where Self: XCTestCase {
     func insert(_ cache: (feed: [LocalFeedImage], timestamp: Date), to sut: FeedStore) -> Error? {
         let exp = expectation(description: "Wait for cache insertion")
         var insertionError: Error?
-        sut.insert(cache.feed, timestamp: cache.timestamp) { error in
-            insertionError = error
+        sut.insert(cache.feed, timestamp: cache.timestamp) { result in
+            switch result {
+            case let .failure(error):
+                insertionError = error
+            default: break
+            }
             exp.fulfill()
         }
         
@@ -25,9 +29,13 @@ extension FeedStoreSpecs where Self: XCTestCase {
     func deleteCache(from sut: FeedStore) -> Error? {
         let exp = expectation(description: "Wait for cache deletion")
         var receivedError: Error?
-        sut.deleteCachedFeed {
+        sut.deleteCachedFeed { result in
             exp.fulfill()
-            receivedError = $0
+            switch result {
+            case let .failure(error):
+                receivedError = error
+            default: break
+            }
         }
         
         wait(for: [exp], timeout: 1.0)

From 40c4569283c4b3b1bfd8078977084539aefe4ec6 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 13:19:37 +0200
Subject: [PATCH 157/159] Simplify `CoreDataFeedStore` completion code with the
 new `Result` APIs

---
 .../CoreData/CoreDataFeedStore.swift          | 54 +++++++++----------
 1 file changed, 25 insertions(+), 29 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift
index 6a9261c..611007f 100644
--- a/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
+++ b/EssentialFeed/EssentialFeed/Feed Cache/Infrastructure/CoreData/CoreDataFeedStore.swift	
@@ -22,33 +22,29 @@ public final class CoreDataFeedStore: FeedStore {
     
     public func retrieve(completion: @escaping RetrievalCompletion) {
         perform { context in
-            
-            do {
-                if let cache = try ManagedCache.find(in: context) {
-                    completion(.success(CacheFeed(feed: cache.localFeed, timestamp: cache.timestamp)))
-                } else {
-                    completion(.success(.none))
+            completion(
+                Result {
+                    try ManagedCache.find(in: context).map {
+                        CacheFeed(feed: $0.localFeed, timestamp: $0.timestamp)
+                    }
                 }
-            } catch {
-                completion(.failure(error))
-            }
+            )
         }
     }
 
     public func insert(_ feed: [LocalFeedImage], timestamp: Date, completion: @escaping InsertionCompletion) {
         perform { context in
-            do {
-                let managedCache = try ManagedCache.newUniqueInstance(in: context)
-                managedCache.timestamp = timestamp
-                managedCache.feed = ManagedFeedImage.images(
-                    from: feed,
-                    in: context
-                )
-                try context.save()
-                completion(.success(()))
-            } catch {
-                completion(.failure(error))
-            }
+            completion(
+                Result {
+                    let managedCache = try ManagedCache.newUniqueInstance(in: context)
+                    managedCache.timestamp = timestamp
+                    managedCache.feed = ManagedFeedImage.images(
+                        from: feed,
+                        in: context
+                    )
+                    try context.save()
+                }
+            )
         }
         
     }
@@ -56,14 +52,14 @@ public final class CoreDataFeedStore: FeedStore {
     
     public func deleteCachedFeed(completion: @escaping DeletionCompletion) {
         perform { context in
-            do {
-                try ManagedCache.find(in: context)
-                    .map(context.delete)
-                    .map(context.save)
-                completion(.success(()))
-            } catch {
-                completion(.failure(error))
-            }
+            completion(
+                Result {
+                    try ManagedCache.find(in: context)
+                        .map(context.delete)
+                        .map(context.save)
+                }
+                
+            )
         }
     }
     

From 04d9704f87c34c78222c89b067b759377fbbb50d Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 13:21:23 +0200
Subject: [PATCH 158/159] Simplify `get`  method of `URLSessionHTTPClient`  by
 leveraging native `Result` initializer

---
 .../FeedApi/URLSessionHTTPClient.swift         | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift b/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift
index e97d481..7860d0b 100644
--- a/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift
+++ b/EssentialFeed/EssentialFeed/FeedApi/URLSessionHTTPClient.swift
@@ -17,13 +17,17 @@ public class URLSessionHTTPClient: HTTPClient {
     
     public func get(from url: URL, completion: @escaping (HTTPClient.Result) -> Void) {
         session.dataTask(with: url)  { data, response, error in
-            if let error {
-                completion(.failure(error))
-            } else if let data, let response = response as? HTTPURLResponse {
-                completion(.success((data, response)))
-            } else {
-                completion(.failure(UnexpectedValuesRepresentation()))
-            }
+            completion(
+                Result {
+                    if let error {
+                        throw error
+                    } else if let data, let response = response as? HTTPURLResponse {
+                        return (data, response)
+                    } else {
+                        throw UnexpectedValuesRepresentation()
+                    }
+                }
+            )
         }
         .resume()
     }

From 2b975bb76da08bd784de2227d686aef004b3ef40 Mon Sep 17 00:00:00 2001
From: Cristian Rojas <cristian.rojas@live.fr>
Date: Wed, 9 Apr 2025 13:25:23 +0200
Subject: [PATCH 159/159] Update CI's xcode version to 16.2

---
 .github/workflows/CI.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 7bf4563..a66f1d2 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -14,7 +14,7 @@ jobs:
     - uses: actions/checkout@v4
 
     - name: Select Xcode
-      run: sudo xcode-select -switch /Applications/Xcode_16.0.app
+      run: sudo xcode-select -switch /Applications/Xcode_16.2.app
       
     - name: Xcode version
       run: /usr/bin/xcodebuild -version