How do you mock the session object collection using Moq

I am using shanselmann's MvcMockHelper class to mock up some HttpContext stuff using Moq but the issue I am having is being able to assign something to my mocked session object in my MVC controller and then being able to read that same value in my unit test for verification purposes.

My question is how do you assign a storage collection to the mocked session object to allow code such as session["UserName"] = "foo" to retain the "foo" value and have it be available in the unit test.

I started with Scott Hanselman's MVCMockHelper, added a small class and made the modifications shown below to allow the controller to use Session normally and the unit test to verify the values that were set by the controller.

/// <summary>
/// A Class to allow simulation of SessionObject
/// </summary>
public class MockHttpSession : HttpSessionStateBase
{
    Dictionary<string, object> m_SessionStorage = new Dictionary<string, object>();

    public override object this[string name]
    {
        get { return m_SessionStorage[name]; }
        set { m_SessionStorage[name] = value; }
    }
}

//In the MVCMockHelpers I modified the FakeHttpContext() method as shown below
public static HttpContextBase FakeHttpContext()
{
    var context = new Mock<HttpContextBase>();
    var request = new Mock<HttpRequestBase>();
    var response = new Mock<HttpResponseBase>();
    var session = new MockHttpSession();
    var server = new Mock<HttpServerUtilityBase>();

    context.Setup(ctx => ctx.Request).Returns(request.Object);
    context.Setup(ctx => ctx.Response).Returns(response.Object);
    context.Setup(ctx => ctx.Session).Returns(session);
    context.Setup(ctx => ctx.Server).Returns(server.Object);

    return context.Object;
}

//Now in the unit test i can do
AccountController acct = new AccountController();
acct.SetFakeControllerContext();
acct.SetBusinessObject(mockBO.Object);

RedirectResult results = (RedirectResult)acct.LogOn(userName, password, rememberMe, returnUrl);
Assert.AreEqual(returnUrl, results.Url);
Assert.AreEqual(userName, acct.Session["txtUserName"]);
Assert.IsNotNull(acct.Session["SessionGUID"]);

It's not perfect but it works enough for testing.

Using Moq 3.0.308.2 here is an example of my account controller setup in my unit test:

    private AccountController GetAccountController ()
    {
      .. setup mocked services..

      var accountController = new AccountController (..mocked services..);

      var controllerContext = new Mock<ControllerContext> ();
      controllerContext.SetupGet(p => p.HttpContext.Session["test"]).Returns("Hello World");
      controllerContext.SetupGet(p => p.HttpContext.User.Identity.Name).Returns(_testEmail);
      controllerContext.SetupGet(p => p.HttpContext.Request.IsAuthenticated).Returns(true);
      controllerContext.SetupGet(p => p.HttpContext.Response.Cookies).Returns(new HttpCookieCollection ());

      controllerContext.Setup (p => p.HttpContext.Request.Form.Get ("ReturnUrl")).Returns ("sample-return-url");
      controllerContext.Setup (p => p.HttpContext.Request.Params.Get ("q")).Returns ("sample-search-term");

      accountController.ControllerContext = controllerContext.Object;

      return accountController;
    }

then within your controller method the following should return "Hello World"

string test = Session["test"].ToString ();