How to Create a Fake HttpContext to Unit Test MVC Controller

Given: I needed to unit test that a response status code had been set within a controller action.
When: I didn't particularly want to refactor due to this being existing code.
Then: After experimenting unsuccessfully with creating various HttpContext classes, I found the simplest solution to be as follows within my test method:

var request = new HttpRequest("", "http://tempuri.org/", "");
var response = new HttpResponse(TextWriter.Null);
var httpContext = new HttpContextWrapper(new HttpContext(request, response));

_myController.ControllerContext = new ControllerContext(httpContext, new RouteData(), _myController);

var result = _myController.SomeAction(...some parameters...);

Assert.AreEqual(400, response.StatusCode);