TDD problem in ASP.NET MVC3 (with DI)

I am attempting to write some Tests for a small project of mine but they seem to fail (I am starting with 1 test 'Create_Class')

I use the repository pattern and use Constructor Dependency Injection:

public KlasController() {

    db = ObjectContextPerHttpRequest.Context;
    KlasRepo = new KlasRepository(db);
    LesRepo = new LesRepository(db);
    OpdrachtRepo = new OpdrachtRepository(db);
}

//dependency injection constructor
public KlasController(IKlasRepository KlasRepo, ILesRepository LesRepo, 
    IOpdrachtRepository OpdrachtRepo) {

    this.KlasRepo = KlasRepo;
    this.LesRepo = LesRepo;
    this.OpdrachtRepo = OpdrachtRepo;
}

here is my TestClass with testinitializer (which runs before every test) and the first test

[TestClass()]
public class KlasControllerTest
{
    private KlasController Controller;
    private IOpdrachtRepository OpdrachtRepo;

    //Use TestInitialize to run code before running each test
    [TestInitialize()]
    public void MyTestInitialize()
    {
        OpdrachtRepo = new DummyOpdrachtRepository();
        Controller = new KlasController(new DummyKlasRepository(),
            new DummyLesRepository(), OpdrachtRepo);
        Opdracht TestOpdracht = new Opdracht
        {
            OpdrachtID = 1,
            VakID = 1,
            StamNummer = "im1"
        };
        Vak TestVak = new Vak { VakID = 1, VakNaam = "FOOP" };
        TestOpdracht.Vak = TestVak;
        OpdrachtRepo.addOpdracht(TestOpdracht);
    }   

    /// <summary&开发者_如何学编程gt;
    ///A test for Index
    ///</summary>
    [TestMethod()]
    public void CreateKlasDirectsToToonKlassen()
    {
        Klas Klas = new Klas { KlasNaam = "2dNet" };
        RedirectToRouteResult view = Controller.Create(1) as RedirectToRouteResult;
        Assert.IsNotNull(view);                
        Assert.AreEqual("ToonKlassen", view.RouteValues["action"]);

    }
}

at the moment I get a nullreferenceException on the view (assert.isNotNull fails)

and here is one of my DummyRepository's:

class DummyOpdrachtRepository : IOpdrachtRepository
{
    List<Opdracht> opdrachten; 

    public DummyOpdrachtRepository()
    {
        opdrachten = new List<Opdracht>();
    }

    public void addOpdracht(Opdracht opdracht)
    {
        opdrachten.Add(opdracht);
    }

    public string GetDocentID(int OpdrachtID)
    {
        var opdracht = opdrachten.Where(o => o.OpdrachtID == OpdrachtID).FirstOrDefault();
        return opdracht.StamNummer;
    }

    public Opdracht Find(int id)
    {
        return opdrachten.Where(o => o.OpdrachtID == id).FirstOrDefault();
    }
}

Normally I should have written the tests Before writting the code, I know (and I am convinced off TDD, as I have used it successfully in my latest Java-project). but it just doesn't seem to work..

here is the code for KlasController.Create action

public ActionResult Create(int id) //id = opdrachtID 
{
    var Opdracht = OpdrachtRepo.Find(id);
    Vak vak;
    if(Opdracht != null)
        vak = Opdracht.Vak;
    else
        throw new NullReferenceException("Deze opdracht werd niet gevonden");
    return View(new CreateKlasModel(id,vak));
} 

I know this is a lot of code, but I really want to make this work.

Thanks for helping me out in advance :)

As vladimir77 already says in his comment, the method public ActionResult Create(int id) is of type ViewResult, so either you change you method to do areturn RedirectToRoute() or you change your test to

ViewResult view = Controller.Create(1);
Assert.IsNotNull(view); 

A ViewResult can not be cast as a RedirectToRouteResult.