Moq 错误：“预期在模拟上至少调用一次，但从未执行”答案

【问题标题】：Moq error: "Expected invocation on the mock at least once, but was never performed"Moq 错误：“预期在模拟上至少调用一次，但从未执行”
【发布时间】：2018-06-13 16:07:32
【问题描述】：

我是 Moq 的新手，我正在努力解决这个错误。我不太确定为什么我会收到我收到的错误。我跟着找到了here的测试代码。

错误：

Moq.MockException：预期至少对模拟调用一次，但从未执行过：c => c.PostAsync(Mock.Object, "You send abc which is 3 characters")

代码

MyTests.cs

[TestClass] 
public class MyTests
{
    private Mock<IChatHelper> _chat;
    private RootDialog _dialog;
    private Mock<IDialogContext> _context;

    public LUISDialogTests()
    {
        _chat = new Mock<IChatHelper>();
        _context = new Mock<IDialogContext>();
        _dialog = new RootDialog(_chat.Object);
    }

    //[SetUp]
    //public void SetUp()
    //{
    //    _chat = new Mock<IChatHelper>();
    //    _dialog = new RootDialog(_chat.Object);
    //    _context = new Mock<IDialogContext>();
    //}

    [TestMethod]
    public async Task Test_CustomerService_Message_LengthAsync()
    {
        var message = Activity.CreateMessageActivity();

        message.Text = "abc";

        _chat.Setup(c => c.PostAsync(_context.Object, message.Text));

        await _dialog.MessageReceivedAsync(_context.Object, Awaitable.FromItem(message));

        _chat.Verify(c => c.PostAsync(_context.Object, "You send abc which was 3 characters"), Times.AtLeastOnce); // Fails here

    }
   }

RootDialog.cs

[Serializable]
public class RootDialog : IDialog<object>
{
  private IChatHelper _chat;

public RootDialog(IChatHelper chat)
{
    _chat = chat;
}

public Task StartAsync(IDialogContext context)
{
    context.Wait(MessageReceivedAsync);
    return Task.CompletedTask;
}

public async Task MessageReceivedAsync(IDialogContext context, IAwaitable<object> result)
{
    var message = await result as Activity;

    int length = (message.Text ?? string.Empty).Length;

    await _chat.PostAsync(context, $"You sent {message.Text} which was {length} characters");

    context.Wait(MessageReceivedAsync);
}

ChatHelper.cs

 public interface IChatHelper
{
    Task PostAsync(IDialogContext context, string message);
}

[Serializable]
public class ChatHelper : IChatHelper
{
    public async Task PostAsync(IDialogContext context, string message)
    {
        await context.PostAsync(message);
    }
}

需要注意的一点：

我所遵循的代码建议使用 [TestFixture] 而不是 [TestClass]。添加 Fixture 时 VS 看不到测试，所以我切换到测试类

【问题讨论】：

标签： c# moq botframework

【解决方案1】：

这是您所期待的消息中的一个字符拼写错误。您的测试代码会这样做：

await _chat.PostAsync(context, $"You sent {message.Text} which was {length} characters");

并且您正在验证是否发生了这种情况：

_chat.Verify(c => c.PostAsync(_context.Object, "You send abc which was 3 characters"), Times.AtLeastOnce); // Fails here

你能看出这两个字符串的区别吗？ sent != send。改变一个或另一个，它可能会开始工作。

【讨论】：