Inject currentDate, locale, and calendar to make tests reliable in an…

…y locale
ullas-jain · Nov 21, 2023 · bd099f5 · bd099f5
1 parent fd84288
commit bd099f5
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Showing 2 changed files with 17 additions and 3 deletions.
diff --git a/EssentialFeed/Image Comments Presentation/ImageCommentsPresenter.swift b/EssentialFeed/Image Comments Presentation/ImageCommentsPresenter.swift
@@ -31,13 +31,20 @@ public final class ImageCommentsPresenter {
                           comment: "Title for the image comments view")
     }
 
-    public static func map(_ comments: [ImageComment]) -> ImageCommentsViewModel {
+    public static func map(
+        _ comments: [ImageComment],
+        currentDate: Date = Date(),
+        calendar: Calendar = .current,
+        locale: Locale = .current
+    ) -> ImageCommentsViewModel {
         let formatter = RelativeDateTimeFormatter()
+        formatter.calendar = calendar
+        formatter.locale = locale
 
         return ImageCommentsViewModel(comments: comments.map { comment in
             ImageCommentViewModel(
                 message: comment.message,
-                date: formatter.localizedString(for: comment.createdAt, relativeTo: Date()),
+                date: formatter.localizedString(for: comment.createdAt, relativeTo: currentDate),
                 username: comment.username
             )
         })

diff --git a/EssentialFeedTests/Image Comments Presentation/ImageCommentsPresenterTests.swift b/EssentialFeedTests/Image Comments Presentation/ImageCommentsPresenterTests.swift
@@ -15,6 +15,8 @@ class ImageCommentsPresenterTests: XCTestCase {
 
     func test_map_createsViewModels() {
         let now = Date()
+        let calendar = Calendar(identifier: .gregorian)
+        let locale = Locale(identifier: "en_US_POSIX")
 
         let comments = [
             ImageComment(
@@ -31,7 +33,12 @@ class ImageCommentsPresenterTests: XCTestCase {
             ),
         ]
 
-        let viewModel = ImageCommentsPresenter.map(comments)
+        let viewModel = ImageCommentsPresenter.map(
+            comments,
+            currentDate: now,
+            calendar: calendar,
+            locale: locale
+        )
 
         XCTAssertEqual(viewModel.comments, [
             ImageCommentViewModel(