Question

I’m looking into JustMock the mocking framework from Telerik. It seems pretty good and all. There is one particular feature that is really interesting for us is what they call Future Mocking. Where basically you can mock an instance that was created inside the method you want to test (bad code I know).

For example :

public void foo()
{
    var service = new MyService();
    service.DoSomething();
}

So this feature will allow to mock the MyService instance used inside that foo() method.

I think TypeMock has similar feature.

I was wondering if there are other framework that allows this? Moq? NMock? FakeItEasy? Do they have this feature? Any other frameworks???

Answer 1

Traditional frameworks like you mention (Moq, NMock, FakeItEasy) work based on production code being loosely coupled. Creating the dependency inside a method (as opposed to passing it in via a parameter or class constructor) makes it such that the seams for injecting fakes (stubs or mocks) would not be possible.

JustMock and TypeMock get around this using profiler APIs (IIRC) to intercept and detour code. Another framework that does this is Miscosoft Moles, soon to be named Fakes in Visual Studio 11.

^{NOTE: Keep in mind though, that the latter frameworks are better
suited to tightly-coupled legacy code where you can’t use dependency injection. Tests
with these frameworks will likely be slower, due to the
overhead from the profiler-like nature of the frameworks. Traditional
frameworks are better suited if you can use dependency injection and want the unit tests to be as fast as possible.}