Any way to use Moq to imitate properties of a real-world constructor automatically?

Question

I've got a controller with a lot of constructor injection:

public MoviesController(ISession session, IClientContext clientContext, PManager pManager, ISegmentationService segmentationService, IGeoLocator geoLocator, IBus bus)
{
    _session = session;
    _clientContext = clientContext;
    _pManager = pManager;
    _segmentationService = segmentationService;
    _geoLocator = geoLocator;
    _bus = bus;
}

From my understanding (just read about Mocking), I've got a lot of Mock object properties to manually set if I wish to make a comprehensive test suite based on this controller.

For one method I'm only using one service (I'd even like to automate that with little effort if possible):

public object Show(Guid id)
{
    var movie = _session.Get<movie>(id);
    return movie;
}

But in another there are many services being used - is there any way to set those Moq objects up quickly? I could really use some examples as I'm new to testing. It's an asp.net mvc project with webapi 1 bundled in (testing the webapi controller here)

Answer 1

As has been said in the comments, if you have common setup code, you can put it in a Setup method that is called automatically from your testing framework before each test. It's decorated with a Setup attribute if you're using Nunit TestInitialize if you're using MStest. If you're using XUnit then it's a bit different.

So, your class might look like this:

public class SomeTests {
    Mock<ISession> _sessionMock;
    Mock<IClientContext> _clientContextMock;

    [Setup]
    public void Setup() {
        _sessionMock = new Mock<ISession>();
        _clientContextMock = new Mock <IClientContext();
    }

    MovieController CreateSut() {
        return new MovieController(_sessionMock.Object, _clientContextMock.Object, ...);
    }

    [Test]
    public void TestSomething() {
        _sessionMock.Setup(x=>...);

        //...

        var sut = CreateSut();

       //...
    }
}  

If you're trying to get away from completely creating the mocks manually, then you might want to look at something like AutoFixture with AutoMoq. Which will automatically supply mock instances when creating objects that accept interfaces. AutoFixture can be quite useful, but there is a learning curve to using it effectively so you might want to look at a tutorial / quickstart.

You could also configure an IOC container to supply mock instances for your test project, although I've never gone down that route myself.

Answer 2

For your example, you only need to mock the session, and can leave all the other dependencies null, since their behaviour should be irrelevant to the behaviour you are testing:

Mock<ISession> mockSession = new Mock<ISesssion>();
MoviesController controller = new MoviesController(mockSession.Object, null,null,null,null,null);

There is no need for you to set up any mocks other than the ones you need for this particular test