Question

I am testing an MVC 3 controller that calls methods on this class:

public class SessionVar
{
    /// <summary>
    /// Gets the session.
    /// </summary>
    private static HttpSessionState Session
    {
        get
        {
            if (HttpContext.Current == null)
                throw new ApplicationException
                                   ("No Http Context, No Session to Get!");

            return HttpContext.Current.Session;
        }
    }

    public static T Get<T>(string key)
    {
        return Session[key] == null ? default(T) : (T)Session[key];
    }
    ...
}

My test method, following recommendations from Hanselman’s Blog is:

[Test]
public void CanRenderEmployeeList()
{
    _mockIEmployeeService.Setup(s => s.GetEmployees(StatusFilter.OnlyActive))
        .Returns(BuildsEmployeeList().Where(e => e.IsApproved));

    var httpContext = FakeHttpContext();
    var target = _employeeController;
    target.ControllerContext = new ControllerContext
                  (new RequestContext(httpContext, new RouteData()), target);
    var result = target.Index();

    Assert.IsNotNull(result);
    Assert.IsInstanceOf<ViewResult>(result);
    var viewModel = target.ViewData.Model;
    Assert.IsInstanceOf<EmployeeListViewModel>(viewModel);
}

public static HttpContextBase FakeHttpContext()
{
    var context = new Mock<HttpContextBase>();
    var request = new Mock<HttpRequestBase>();
    var response = new Mock<HttpResponseBase>();
    var session = new Mock<HttpSessionStateBase>();
    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.Object);
    context.Setup(ctx => ctx.Server).Returns(server.Object);

    return context.Object;
}

But my test keeps failing, I get:

CanRenderEmployeeListSystem.ApplicationException : No Http Context, 
                                                          No Session to Get!

which is the Exception message to be thrown when HttpContext.Current == null

I just need the Session object to ‘exist’, not the actual values stored on the Session.

Can you tell me what am I doing wrong?

Thanks.

Answer 1

In the long run, you’ll be happier if you create an interface for the SessionVar class. Use your current implementation (via Dependency Injection) at runtime. Plug in a mock during testing. Removes the need for mocking out all of those Http runtime dependencies.