Question

I have a test where I pass in an object like so:

var repo = new ActualRepo();

var sut = new Sut(repo);

In my test, Repo has one method that I need to actually execute, whilst another method I want to mock out and not execute.

So for example, take this pseudocode:

var repo = new Mock<IRepo>();

repo.Setup(m => m.MethodIWantToCall()).WillBeExecuted();
repo.Setup(m => m.MethodIWantToMock()).Returns(false);

Using Moq, is this possible and how can it be done?

EDIT:
I’ve used TypeMock in the past and you can do something like.

Isolator.When(() => repo.MethodToIgnore()).WillBeIgnored();
Isolator.When(() => repo.MethodToActuallyRun()).WillBeExecuted();

Answer 1

You can’t do this with Moq if you use the same object unless one of the method is virtual and you are basing your mock on a type rather than an interface.

That’s because when you are passing a mock object based on an interface, you aren’t passing a real object so it does not have access to the real methods of the object.

You are passing a dynamic proxy which will respond to methods it has been setup to respond to.

I believe TypeMock rewrites the assemblies at runtime to achieve this, something Moq definitively doesn’t do.

If you want to achieve similar results with Moq:

• You could mock both methods
• You would have to extract both methods to different dependencies so as to mock one dependency and not the other.
• You could have the method you need mocked be virtual, which would be the solution I would prefer.

EDIT : I edited my answer for correctness after reading AlanT’s answer.