单元测试异步方法

Question

我在单元测试异步方法时遇到了一些问题.

这是我的单元测试代码:

        [TestMethod]
    public async Task TestRefreshList_RefreshesList()
    {
        int countBeforeAdd = listViewModel.NotesTitles.Count;

        // Add a note.
        await listViewModel.NoteRepository.AddNoteAsync(new Note { Title = String.Empty, Content = String.Empty });

        // Refresh.
        await listViewModel.RefreshList();

        int countAfterAdd = listViewModel.NotesTitles.Count;

        // Assert that the count increased by 1 and that it matches the count of the repository.
        Assert.IsTrue(countAfterAdd == countBeforeAdd + 1 && countAfterAdd == mockNoteRepository.FakeNotes.Count);
    }

当我运行此测试时,似乎永远不会超过第一个await语句.如果有帮助,以下是测试中的方法:

    public ObservableCollection<Note> FakeNotes { get; set; }

    public Task AddNoteAsync(Models.Note note)
    {
        return new Task(() => 
        {
            FakeNotes.Add(note);
        });
    }

    public Task<ObservableCollection<string>> GetAllNoteTitlesAsync()
    {
        // Return the titles of the notes in the FakeNotes collection.
        return new Task<ObservableCollection<string>>(() =>
        {
            return new ObservableCollection<string>(FakeNotes.Select(n => n.Title));
        });
    }

....

        public async Task RefreshList()
    {
        try
        {
            NotesTitles = await NoteRepository.GetAllNoteTitlesAsync();
        }
        catch (Exception)
        {
            Notifier.Notify("We encountered an error when trying to load your notes. Please try again. ", "Ooops!");
        }
    }

任何帮助,将不胜感激.谢谢.

Answer 1

你的Tasks永远不会开始.尝试使用Task.Run而不是Task构造函数.