Question

I’ve got a strange behavior when using Match.Create with Moq.

The following code snippet doesn’t pass, when I extract Match.Create as a variable:

      var mock = new Mock<IA>();
      mock.Object.Method ("muh");
      mock.Verify (m => m.Method (Match.Create<string> (s => s.Length == 3)));

      public interface IA
      {
        void Method (string arg);
      }

What is the reason?

Answer 1

Thanks both of you. But I found another good solution for this. As in the quick start described, you can also use a method. First I thought it would make no difference, whether I use a variable or method. But obviously Moq is clever enough. So the expression and predicate stuff can be converted into:

public string StringThreeCharsLong ()
{
  return Match.Create<string> (s => s.Length == 3);
}

I think this is great, because it reduces the noise in unit tests.

MyMock.Verify (m => m.Method (StringThreeCharsLong());