asp.net mvc How to test controllers correctly

Question

Hi,

I'm having difficulty testing controllers. Original my controller for testing looked something like this:

SomethingController CreateSomethingController()
{
    var somethingData = FakeSomethingData.CreateFakeData();
    var fakeRepository = FakeRepository.Create();

    var controller = new SomethingController(fakeRepository);

    return controller;
}

This works fine for the majority of testing until I got the Request.IsAjaxRequest() part of code. So then I had to mock up the HttpContext and HttpRequestBase. So my code then changed to look like:

public class FakeHttpContext : HttpContextBase
{
    bool _isAjaxRequest;

    public FakeHttpContext( bool isAjaxRequest = false )
    {
        _isAjaxRequest = isAjaxRequest;
    }

    public override HttpRequestBase Request
    {
        get
        {
            string ajaxRequestHeader = "";

            if ( _isAjaxRequest )
                ajaxRequestHeader = "XMLHttpRequest";

            var request = new Mock<HttpRequestBase>();
            request.SetupGet( x => x.Headers ).Returns( new WebHeaderCollection 
            {
                {"X-Requested-With", ajaxRequestHeader} 
            } );

            request.SetupGet( x => x["X-Requested-With"] ).Returns( ajaxRequestHeader );

            return request.Object;
        }
    }

    private IPrincipal _user;

    public override IPrincipal User
    {
        get
        {
            if ( _user == null )
            {
                _user = new FakePrincipal();
            }
            return _user;
        }
        set
        {
            _user = value;
        }
    }
}


SomethingController CreateSomethingController()
{
    var somethingData = FakeSomethingData.CreateFakeData();
    var fakeRepository = FakeRepository.Create();

    var controller = new SomethingController(fakeRepository);

    ControllerContext controllerContext = new ControllerContext( new FakeHttpContext( isAjaxRequest ), new RouteData(), controller );
     controller.ControllerContext = controllerContext;

    return controller;
}

Now its got to that stage in my controller where I call Url.Route and Url is null. So it looks like I need to start mocking up routes for my controller.

I seem to be spending more time googling on how to fake/mock objects and then debugging to make sure my fakes are correct than actual writing the test code. Is there an easier way in to test a controller? I've looked at the TestControllerBuilder from MvcContrib which helps with some of the issues but doesn't seem to do everything. Is there anything else available that will do the job and will let me concentrate on writing the tests rather than writing mocks?

Thanks

Answer 1

You can use some of the libraries that give you out of the box some of these objects. For example RhinoMock, NMock ... etc. I personally use Moq - it's good enough and free. What i like most in Moq is the linq expressions.

Answer 2

Most mocking engine will do all this for you. I use RhinoMocks but there are a lot more available. Also Moles is very new and interesting mocking engine (this generally comes with Pex which is yet more ammo in your unit testing arsenal)

Answer 3

MvcContrib + RhinoMocks. Check out the TestControllerBuilder in the MvcContrib.TestHelper library. Here's the official write-up: http://mvccontrib.codeplex.com/wikipage?title=TestHelper#Examples.

Here's an example of mocking a controller out for testing a UrlHelper: http://stackoverflow.com/questions/1367616/asp-net-mvc-mock-controller-url-action

Here's a short explanation of how to use the TestControllerBuilder: http://codebetter.com/blogs/kyle.baley/archive/2008/03/19/testcontrollerbuilder-in-mvccontrib.aspx

Answer 4

Instead of mocking stuff, you can pass IAjaxRequest to constructor. Or make it base constructor class property (and use property injection). Or you can make your constructor implement IAjaxRequest and then apply global action filter on base constructor class that will setup IAjaxRequest.

This will help to abstract many things, including HttpContext stuff. Just don't abstract IHttpContext, abstract IUserContext, ISessionStorage, IAuthentication, IRequestDetails...

Another way is to use model binder directly on methods where you need specific information. See this post for example. You can make binder that will give you IsAjaxRequest, then you just make action to accept this parameter. Works very well because information is provided exactly to the method that needs it, not to the whole controller.