[ASP.NET MVC] Controller constructor called on every request

Question

I'm trying to test a very simple form that uses only a list and a create. This is the controller:

public class PositionsController : Controller
{
    private readonly IPositionRepository _positions;

    // default constructor
    public PositionsController()
    {
        _positions = new TestPositionRepository();
    }

    // DI constructor
    public PositionsController(IPositionRepository positions)
    {
        _positions = positions;
    }

    // get a list of all positions
    public ActionResult Index()
    {
        return View(_positions.GetAllPositions());
    }

    // get initial create view
    public ActionResult Create()
    {
        return View();
    } 

    // add the new Position to the list
    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult Create(Position positionToAdd)
    {
        try
        {
            _positions.AddPosition(positionToAdd);

            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }
}

TestPositionRepository is simply a mock repository I've created in order to test out dependency injection. Whenever I try to create a new entry, I get sent back to the index view, but the new entry is not added to the list. Using the debugger, it's showing that the constructor is called every time I click on a link or navigate to a link within the controller's control. Is there a way to fix this problem? I have the feeling that I'm doing it wrong. What I'm trying to do is dependency injection using Ninject but I'm stuck on this problem so far.

Answer 1

Why is this a problem - it's the way ASP.NET requests work. Each request runs up it's own instance of the asp.net page, or the MVC controller, and when the request is done, the controller is discarded - neither of these things persist between requests.

Thus in your create method you should be calling the repository's save/commit method after adding your new position.

Answer 2

A MockRepository will be stateless in most cases. Thats why you will not see an added entry in Index. I would test Index and Create seperately. For index I would only check if an existing entry is displayed correctly. This means your MockRepository should have some existing entries hardcoded in it for the GetPositions - Method.

If you want to test the flow through the application (what Create + Index already is) I would use an integration test on a real respository.