Question

I have implemented my mvc base controller called DefaultController using dependency injection pattern in order to be able to construct test cases. Example below:

public class DefaultController : Controller
{
    protected readonly ISessionHelper _sessionHelper;
    string _thisUserOpenID;
    protected IUsersRepository _UserRepository;
 ... 
    public DefaultController()
    { } //not for testing

    public DefaultController(ISessionHelper session, IUserRepository repo)
    {
       _sessionHelper=session;
       _UserRepository = repo;
     }
 }

Then I have my controllers using this controller, homecontroller, usercontroller, etc.

Now, building some test cases I found myself in a situation where I don’t know how to actually use the injection dependency pattern.

    [TestMethod]
    public void Welcome_Message_In_ViewData_Has_Coockie_User_Display_Name()
    {
        // Below I want to insert FakeRepositories using 
        //ISessionHelper and so on. but the constructor 
        //for homecontroller don't have it.
        HomeController controller = new HomeController(); 

Any ideas?

Answer 1

Your HomeController needs to have a matching “injectable” constructor, which would then call the base constructor.

public HomeController(ISessionHelper session, IUserRepository repo)
  : base(session, repo)
    {

    }

Now, in your test, you would create your HomeController using that constructor, and pass in a mocked up session and user repository. Speaking of mocking, you might also be interested in Scott Hanselman’s MvcMockHelpers classes, with code for many popular mocking frameworks.