ASP.Net MVC TDD using Moq - asp.net

Question

I am trying to learn TDD/BDD using NUnit and Moq.
The design that I have been following passes a DataService class to my controller to provide access to repositories.
I would like to Mock the DataService class to allow testing of the controllers.
There are lots of examples of mocking a repository passed to the controller but I can't work out how to mock a DataService class in this
scenerio.
Could someone please explain how to implement this?
Here's a sample of the relevant code:
[Test]
public void Can_View_A_Single_Page_Of_Lists()
{
var dataService = new Mock<DataService>();
var controller = new ListsController(dataService);
...
}
namespace Services
{
public class DataService
{
private readonly IKeyedRepository<int, FavList> FavListRepository;
private readonly IUnitOfWork unitOfWork;
public FavListService FavLists { get; private set; }
public DataService(IKeyedRepository<int, FavList> FavListRepository,
IUnitOfWork unitOfWork)
{
this.FavListRepository = FavListRepository;
this.unitOfWork = unitOfWork;
FavLists = new FavListService(FavListRepository);
}
public void Commit()
{
unitOfWork.Commit();
}
}
}
namespace MyListsWebsite.Controllers
{
public class ListsController : Controller
{
private readonly DataService dataService;
public ListsController(DataService dataService)
{
this.dataService = dataService;
}
public ActionResult Index()
{
var myLists = dataService.FavLists.All().ToList();
return View(myLists);
}
}
}

Answer 1

Create an interface like this:
public interface DataService
{
FavListService FavLists { get; }
void Commit();
}
Make your DataService implement this interface and your controller should depend on this interface. Problem solved :)
EDIT: This line of code:
dataService.FavLists.All().ToList();
is breaking the law of demeter and will be a pain to unit test your service. Create a method like AllFavList() on your service instead of all these chain of calls, it will be easier to mock.
EDIT2: How to mock you get property
dataService.SetupGet(d => d.FavLists).Returns(your_variable);