Using Moq to determine if a method is called

Question

It is my understanding that I can test that a method call will occur if I call a higher level method, i.e.:

public abstract class SomeClass()
{    
    public void SomeMehod()
    {
        SomeOtherMethod();
    }

    internal abstract void SomeOtherMethod();
}

I want to test that if I call SomeMethod() then I expect that SomeOtherMethod() will be called.

Am I right in thinking this sort of test is available in a mocking framework?

Solution 1

You can see if a method in something you have mocked has been called by using Verify, e.g.:

static void Main(string[] args)
{
        Mock<ITest> mock = new Mock<ITest>();

        ClassBeingTested testedClass = new ClassBeingTested();
        testedClass.WorkMethod(mock.Object);

        mock.Verify(m => m.MethodToCheckIfCalled());
}

class ClassBeingTested
{
    public void WorkMethod(ITest test)
    {
        //test.MethodToCheckIfCalled();
    }
}

public interface ITest
{
    void MethodToCheckIfCalled();
}

If the line is left commented it will throw a MockException when you call Verify. If it is uncommented it will pass.

Solution 2

No, mock testing assumes you are using certain testable design patterns, one of which is injection. In your case you would be testing SomeClass.SomeMethod and SomeOtherMethod must be implemented in another entity which needs to be interfaced.

Your Someclass constructor would look like New(ISomeOtherClass). Then you would mock the ISomeOtherClass and set expectation on its SomeOtherMethod to be called and verify the expectation.

Comments

[Admin]

This is the correct answer. You must understand something, however. You CANNNOT mock a method/property that is not abstract or virtual (obviously, all interface methods and properties can be mocked).

[Raymond]

-1: The .Expect(...).Verifiable() is redundant in this code. Using AAA the verify you have is just right. .Verifiable is for usage with .Verify() i,.e. the no arg version. See stackoverflow.com/questions/980554/…

[reggaeguitar]

@I-- yes it can

[reggaeguitar]

Downvoted because it's more complicated and requires a boilerplate DummyClass

[wickdninja]

upvoted because sometimes you cannot refactor and you need to test the implementation as it stands