Mocking the Controller Context using Rhino Mock

When using ASP.NET MVC 5, its easy to write unit tests around the framework due to the various abstractions provided.

Stephen Walther provides a good overview of the different objects. Whenever you need to interact with the request, response, session or browser, the following objects can be mocked using your mocking framework of choice:

• HttpRequestBase
• HttpResponseBase
• HttpSessionBase
• HttpBrowserCapabilitiesBase

Here of some examples using of mocking the various classes using Rhino Mock:

Mocking the Controller Context (MVC)

	public void SetUpControllerContext()
	{
	// Setup the controller context plumbing
	var httpContext = MockRepository.GenerateMock<HttpContextBase>();
	var httpRequest = MockRepository.GenerateMock<HttpRequestBase>();
	var httpResponse = MockRepository.GenerateMock<HttpReponseBase>();
	var browserMock = MockRepository.GenerateMock<HttpBrowserCapabilitiesBase>();
	// Set the required test values
	httpContext.Stub(h => h.Request.Browser).Return(browserMock);
	httpContext.Stub(h => h.Request).Return(httpRequest);
	// Now create the system under test
	var repository = MockRepository.GenerateMock<Repository>();
	var controller = new CustomerController(repository);
	controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), _controller);
	controller.Create();
	// Assertions
	}

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Mocking the Controller Context (Web API)

	var controller = new TestController();
	var config = new HttpConfiguration();
	var request = new HttpRequestMessage(HttpMethod.Get, "http://localhost/api/test");
	var route = config.Routes.MapHttpRoute("default", "api/{controller}/{id}");
	var routeData = new HttpRouteData(route, new HttpRouteValueDictionary { { "controller", "test" } });
	controller.ControllerContext = new HttpControllerContext(config, routeData, request);
	controller.Request = request;
	controller.Request.Properties[HttpPropertyKeys.HttpConfigurationKey] = config;

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Mocking the Identity and Principal

	public void SetUpHttpRequestUser()
	{
	// Setup the controller context plumbing
	var httpContext = MockRepository.GenerateStub<HttpContextBase>();
	var identity = MockRepository.GenerateStub<IIdentity>();
	var principal = MockRepository.GenerateStub<IPrincipal>();
	// Set the required test values
	identity.Stub(i => i.Name).Return("TestUser");
	principal.Stub(u => u.Identity).Return(identity);
	httpContext.User = new GenericPrincipal(new GenericIdentity(String.Empty), new string[0]);
	;
	// Now create the system under test
	var repository = MockRepository.GenerateMock<Repository>();
	var controller = new CustomerController(repository);
	var controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), _controller);
	controller.Create();
	// Assertions
	}

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Mocking the Session State

	public void SetUpSession()
	{
	// Arrange
	var httpContext = MockRepository.GenerateStub<HttpContextBase>();
	var httpSession = MockRepository.GenerateStub<HttpSessionStateBase>();
	httpContext.Stub(h => h.Session).Return(httpSession);
	mock.Setup(p => p.HttpContext.Session).Returns(mockSession.Object);
	// Now create the system under test
	var repository = MockRepository.GenerateMock<Repository>();
	var controller = new CustomerController(repository);
	var controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), _controller);
	controller.Create();
	// Assertions
	Assert.AreEqual("testuser1", controller.HttpContext.Session["Username"]);
	}

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