Using Moq to mock only some methods

Question

I have the following method:

public CustomObect MyMethod()
{
    var lUser = GetCurrentUser();
    if (lUser.HaveAccess)
    {
        //One behavior
    }
    else 
    {
        //Other behavior
    }

    //return CustomObject
}

I want to mock IMyInterface.GetCurrentUser, so that while calling MyMethod I could get to one of the code paths to check it. How to do that with Moq?

I'm doing the following thing:

var moq = new Mock<IMyInterface>();
moq.Setup(x => x.GetCurrentUser()).Returns(lUnauthorizedUser);

//act
var lResult = moq.Object.MyMethod();

But for some reason lResult is always null, and when I'm trying to get into MyMethod in debug, I'm always skipping to the next statement.

Answer 1

This is called a partial mock, and the way I know to do it in Moq requires mocking the class rather than the interface and then setting the "Callbase" property on your mocked object to "true".

This will require making all the methods and properties of the class you are testing virtual. Assuming this isn't a problem, you can then write a test like this:

var mock = new Mock<YourTestClass>();
mock.CallBase = true;
mock.Setup(x => x.GetCurrentUser()).Returns(lUnauthorizedUser);
mockedTest.Object.MyMethod();