Mocking HttpContext (Session)

Question

I've read many articles and blogs about mocking in mvc... Many of them were helpful, but i still have some problems:

• One such issue is that I need to use Session in My ActionResult, but in my Tests i get a NullReferenceException when Session is accessed.

  public ActionResult Index()
  {
    if (Session["Something"] == null)
    {
      Session.Add("Something", <smth>);
    }
    else
    {
      Session["Something"] = <smth>;
    }
    return redirect to action("Index2");
  }
  

• My test look like this:

  HomeController controller = new HomeController;
  var result = controller.Index() as ViewResult;
  Assert.AreEqual("Index2", result.ViewName);
  

Answer 1

You can use tools such as the MVC-contrib TestHelper

This sample from the site shows how to test an action that stores a posted form value in the session

[Test]
public void AddSessionStarShouldSaveFormToSession()
{
    TestControllerBuilder builder = new TestControllerBuilder();
    StarsController controller = new StarsController();
    builder.InitializeController(controller);

    //note that this is assigned before the controller action. This simulates the server  filling out the form data from the request
    builder.Form["NewStarName"] = "alpha c";

    //this assumes that AddSessionStar takes the form data and adds it to the session
    controller.AddSessionStar();

    Assert.AreEqual("alpha c", controller.HttpContext.Session["NewStarName"]);
}