feat: TaskDeletion_FailsForOne_NotifiesOnceAndAllowsDeletingItToTheRestOfRepositories

Author: Xiphereal

Desktop.Tests/UnitTests/TaskListViewModelTests.cs

@@ -87,6 +87,41 @@ public void TaskDeletion_Fails_MessageNotifiesUserAndTaskRemains()
         sut.Tasks.Should().Contain(existingTask);
     }
 
+    [Test]
+    public async Task
+        TaskDeletion_FailsForOne_NotifiesOnceAndAllowsDeletingItToTheRestOfRepositories()
+    {
+        // Arrange.
+        var existingTask = DesktopTask();
+        var aRepository =
+            new InMemoryTaskRepository([existingTask]);
+        var anotherRepository =
+            new InMemoryTaskRepository([existingTask]);
+
+        var messageNotifierMock = new Mock<IMessageNotifier>();
+
+        var sut = TaskListViewModel(
+            [aRepository, anotherRepository],
+            messageNotifierMock.Object);
+        sut.PopulateTasks();
+        aRepository.FailAlways();
+
+        // Act.
+        sut.Delete.Execute(existingTask);
+
+        // Assert.
+        messageNotifierMock.Verify(
+            x => x.Notify(
+                "Task deletion has failed due to " +
+                "an internal error. The Task won't be deleted. " +
+                "Please, try again later."),
+            Times.Once);
+        sut.Tasks.Should().BeEmpty();
+
+        var result = await anotherRepository.All();
+        result.Tasks.Should().BeEmpty();
+    }
+
     private static TaskListViewModel TaskListViewModel(
         params InMemoryTaskRepository[] taskRepositories)
     {
@@ -106,4 +141,14 @@ private static TaskListViewModel TaskListViewModel(
             new TaskCreationViewModel(messageNotifier, [taskRepository]),
             messageNotifier);
     }
+
+    private static TaskListViewModel TaskListViewModel(
+        InMemoryTaskRepository[] taskRepositories,
+        IMessageNotifier messageNotifier)
+    {
+        return new TaskListViewModel(
+            taskRepositories,
+            new TaskCreationViewModel(messageNotifier, taskRepositories),
+            messageNotifier);
+    }
 }

Desktop/Project/TaskListViewModel.cs

@@ -10,7 +10,7 @@ namespace Desktop.Project;
 
 public class TaskListViewModel : ViewModelBase
 {
-    private readonly IEnumerable<ITaskRepository> taskRepositories;
+    private readonly IReadOnlyList<ITaskRepository> taskRepositories;
     private readonly IMessageNotifier messageNotifier;
     public ObservableCollection<Task> Tasks { get; } = [];
 
@@ -21,7 +21,7 @@ public TaskListViewModel(
         TaskCreationViewModel taskCreationViewModel,
         IMessageNotifier messageNotifier)
     {
-        this.taskRepositories = taskRepositories;
+        this.taskRepositories = taskRepositories.ToArray();
         this.messageNotifier = messageNotifier;
 
         Add = new RelayCommand(() =>
@@ -36,18 +36,18 @@ public TaskListViewModel(
 
         Delete = new AsyncRelayCommand<Task>(async taskToRemove =>
         {
-            foreach (var repository in this.taskRepositories)
-            {
-                var deletion = await repository.Delete(taskToRemove!);
-
-                if (deletion.Succeeded)
-                    Tasks.Remove(taskToRemove!);
-                else
-                    messageNotifier.Notify(
-                        "Task deletion has failed due to " +
-                        "an internal error. The Task won't be deleted. " +
-                        "Please, try again later.");
-            }
+            var deletingTasks = this.taskRepositories
+                .Select(x => x.Delete(taskToRemove!));
+            var results = await SystemTask.WhenAll(deletingTasks);
+
+            if (results.Any(x => !x.Succeeded))
+                messageNotifier.Notify(
+                    "Task deletion has failed due to " +
+                    "an internal error. The Task won't be deleted. " +
+                    "Please, try again later.");
+
+            if (results.Any(x => x.Succeeded))
+                Tasks.Remove(taskToRemove!);
         });
     }