Adds internal DeleteFile method DynamicsValue/fake-xrm-easy#157

src/FakeXrmEasy.Core/FileStorage/Db/Exceptions/CouldNotDeleteFileException.cs

@@ -0,0 +1,19 @@
+using System;
+
+namespace FakeXrmEasy.Core.FileStorage.Db.Exceptions
+{
+    /// <summary>
+    /// Exception thrown when a particular file could not be deleted or it doesn't exists
+    /// </summary>
+    public class CouldNotDeleteFileException: Exception
+    {
+        /// <summary>
+        /// Default constructor
+        /// </summary>
+        /// <param name="fileId"></param>
+        internal CouldNotDeleteFileException(string fileId) : base($"Could not delete file with Id '{fileId}'")
+        {
+
+        }
+    }
+}

src/FakeXrmEasy.Core/FileStorage/Db/IInMemoryFileDbInternal.cs

@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+
+namespace FakeXrmEasy.Core.FileStorage.Db
+{
+    internal interface IInMemoryFileDbInternal
+    {
+        List<FileAttachment> GetAllFiles();
+        void AddFile(FileAttachment fileAttachment);
+        void DeleteFile(string fileId);
+    }
+}

src/FakeXrmEasy.Core/FileStorage/Db/InMemoryFileDb.cs

@@ -13,7 +13,7 @@
 
 namespace FakeXrmEasy.Core.FileStorage.Db
 {
-    internal class InMemoryFileDb : IInMemoryFileDbUploader, IInMemoryFileDbDownloader
+    internal class InMemoryFileDb : IInMemoryFileDbUploader, IInMemoryFileDbDownloader, IInMemoryFileDbInternal
     {
         private readonly ConcurrentDictionary<string, FileUploadSession> _uncommittedFileUploads;
         private readonly ConcurrentDictionary<string, FileAttachment> _files;
@@ -69,19 +69,28 @@ public List<FileUploadSession> GetAllFileUploadSessions()
         }
 
         #region Internal File Manipulation
-        internal List<FileAttachment> GetAllFiles()
+        public List<FileAttachment> GetAllFiles()
         {
             return _files.Values.ToList();
         }
 
-        internal void AddFile(FileAttachment fileAttachment)
+        public void AddFile(FileAttachment fileAttachment)
         {
             var wasAdded = _files.TryAdd(fileAttachment.Id, fileAttachment);
             if (!wasAdded)
             {
                 throw new CouldNotAddFileException();
             }
         }
+
+        public void DeleteFile(string fileId)
+        {
+            var wasDeleted = _files.TryRemove(fileId, out var file);
+            if (!wasDeleted)
+            {
+                throw new CouldNotDeleteFileException(fileId);
+            }
+        }
         #endregion
 
         /// <summary>

tests/FakeXrmEasy.Core.Tests/FileStorage/Db/DeleteFileTests.cs

@@ -0,0 +1,62 @@
+using System;
+using DataverseEntities;
+using FakeXrmEasy.Core.Db;
+using FakeXrmEasy.Core.FileStorage.Db;
+using FakeXrmEasy.Core.FileStorage.Db.Exceptions;
+using FakeXrmEasy.Core.FileStorage.Download;
+using Microsoft.Xrm.Sdk;
+using Xunit;
+using FileAttachment = FakeXrmEasy.Core.FileStorage.Db.FileAttachment;
+
+namespace FakeXrmEasy.Core.Tests.FileStorage.Db
+{
+    public class DeleteFileTests
+    {
+        private readonly InMemoryDb _db;
+        private readonly InMemoryFileDb _fileDb;
+        private readonly Entity _entity;
+        private readonly FileAttachment _file;
+
+        public DeleteFileTests()
+        {
+            _db = new InMemoryDb();
+            _fileDb = new InMemoryFileDb(_db);
+
+            _entity = new Entity(dv_test.EntityLogicalName)
+            {
+                Id = Guid.NewGuid()
+            };
+
+            _file = new FileAttachment()
+            {
+                Id = Guid.NewGuid().ToString(),
+                MimeType = "application/pdf",
+                FileName = "TestFile.pdf",
+                Target = _entity.ToEntityReference(),
+                AttributeName = "dv_file",
+                Content = new byte[] { 1, 2, 3, 4 }
+            };
+        }
+
+        [Fact]
+        public void Should_be_empty_when_no_files_are_added()
+        {
+            Assert.Empty(_fileDb.GetAllFiles());
+        }
+
+        [Fact]
+        public void Should_throw_exception_when_a_file_doesnt_exists()
+        {
+            Assert.Throws<CouldNotDeleteFileException>(() => _fileDb.DeleteFile("invalid id"));
+        }
+
+        [Fact]
+        public void Should_delete_an_existing_file()
+        {
+            _fileDb.AddFile(_file);
+            _fileDb.DeleteFile(_file.Id);
+
+            Assert.Empty(_fileDb.GetAllFiles());
+        }
+    }
+}