CODEWITHSUNDEEP
c#moqbotframework
Tony D.
Tony D.

Reputation: 560

Moq error: "Expected invocation on the mock at least once, but was never performed"

I'm new to Moq and I'm struggling with this error. I'm not quite sure why I'm receiving the error that I am getting. I was following along with the test code found here.

Error:

Moq.MockException: Expected invocation on the mock at least once, but was never performed: c => c.PostAsync(Mock.Object, "You send abc which was 3 characters")

Code

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);
    }
}

One thing to note:

Upvotes: 2

Views: 5202

Answers (1)

Richardissimo
Richardissimo

Reputation: 5775

It's a one character typo in the message you are expecting. Your code under test does this:

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

and you are verifying that this happened:

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

Can you spot the difference in the two strings? sent != send. Change one or other, and it'll probably start working.

Upvotes: 4

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