Deletes a file when an update to the file attribute is set to null Dy…

…namicsValue/fake-xrm-easy#157

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

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Microsoft.Xrm.Sdk;
 
 namespace FakeXrmEasy.Core.FileStorage.Db
 {
@@ -7,5 +8,6 @@ internal interface IInMemoryFileDbInternal
         List<FileAttachment> GetAllFiles();
         void AddFile(FileAttachment fileAttachment);
         void DeleteFile(string fileId);
+        List<FileAttachment> GetFilesForTarget(EntityReference target);
     }
 }

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

@@ -98,6 +98,15 @@ public void DeleteFile(string fileId)
             entity[file.AttributeName] = null;
             table.Replace(entity);
         }
+
+        public List<FileAttachment> GetFilesForTarget(EntityReference target)
+        {
+            return _files.Values.Where
+                    (f => 
+                        f.Target.LogicalName.Equals(target.LogicalName) && 
+                        f.Target.Id.Equals(target.Id))
+                .ToList();
+        }
         #endregion
 
         /// <summary>

src/FakeXrmEasy.Core/XrmFakedContext.Crud.cs

@@ -174,8 +174,31 @@ public void UpdateEntity(Entity e)
                     _service.Execute(request);
                 }
             }
+
+            DeleteAssociatedFiles(e);
         }
 
+        /// <summary>
+        /// Deletes any associated files to an entity that has their file attributes as null
+        /// </summary>
+        /// <param name="e"></param>
+        private void DeleteAssociatedFiles(Entity e)
+        {
+            var associatedFiles = FileDb.GetFilesForTarget(e.ToEntityReference());
+
+            foreach (var updatedAttribute in e.Attributes.Keys)
+            {
+                if (e[updatedAttribute] == null)
+                {
+                    var associatedFile = associatedFiles.FirstOrDefault(f => f.AttributeName.Equals(updatedAttribute));
+                    if (associatedFile != null)
+                    {
+                        FileDb.DeleteFile(associatedFile.Id);
+                    }
+                }
+            }
+        }
+
         /// <summary>
         /// Returns an entity record by logical name and primary key
         /// </summary>

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

@@ -0,0 +1,7 @@
+namespace FakeXrmEasy.Core.Tests.FileStorage.Db
+{
+    public class InMemoryFileDbInternalTests
+    {
+
+    }
+}

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

@@ -0,0 +1,60 @@
+using System;
+using DataverseEntities;
+using FakeXrmEasy.Core.Db;
+using FakeXrmEasy.Core.FileStorage.Db;
+using Microsoft.Xrm.Sdk;
+using Xunit;
+using FileAttachment = FakeXrmEasy.Core.FileStorage.Db.FileAttachment;
+
+namespace FakeXrmEasy.Core.Tests.FileStorage.Db
+{
+    public class UpdateFileTests: FakeXrmEasyTestsBase
+    {
+        private const string FILE_ATTRIBUTE_NAME = "dv_file";
+
+        private readonly InMemoryDb _db;
+        private readonly InMemoryFileDb _fileDb;
+        private readonly Entity _entity;
+        private readonly FileAttachment _file;
+
+        public UpdateFileTests()
+        {
+            _db = (_context as XrmFakedContext).Db;
+            _fileDb = (_context as XrmFakedContext).FileDb;
+
+            _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 = FILE_ATTRIBUTE_NAME,
+                Content = new byte[] { 1, 2, 3, 4 }
+            };
+
+            _entity[FILE_ATTRIBUTE_NAME] = _file.Id;
+        }
+
+        [Fact]
+        public void Should_remove_file_when_updating_file_attribute_to_null()
+        {
+            _fileDb.AddFile(_file);
+            _context.Initialize(_entity);
+
+            var entityToUpdate = new Entity(_entity.LogicalName)
+            {
+                Id = _entity.Id,
+                [FILE_ATTRIBUTE_NAME] = null
+            };
+
+            _service.Update(entityToUpdate);
+
+            Assert.Empty(_fileDb.GetAllFiles());
+        }
+    }
+}