Unit Test Linq to Sql in ASP.Net MVC with Moq
April 4, 2008
I have just spent the entire day playing with Moq to unit test an asp.net mvc application I am working with. All I wanted to do is test a “create” method that simply adds a record to the database. So here it goes.
1. I created a Mock Http context to be used by my controller. I modified the Moq version of the MvcMockHelpers class from Scott Hanselman and added two more methods to mock an authenticated user
public static HttpContextBase FakeAuthenticatedHttpContext() { 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>(); var user = new Mock<IPrincipal>(); var identity = new Mock<IIdentity>(); context.Expect(ctx => ctx.Request).Returns(request.Object); context.Expect(ctx => ctx.Response).Returns(response.Object); context.Expect(ctx => ctx.Session).Returns(session.Object); context.Expect(ctx => ctx.Server).Returns(server.Object); context.Expect(ctx => ctx.User).Returns(user.Object); user.Expect(ctx => ctx.Identity).Returns(identity.Object); identity.Expect(id => id.IsAuthenticated).Returns(true); identity.Expect(id => id.Name).Returns(“test”); return context.Object; }
public static void SetFakeAuthenticatedControllerContext(this Controller controller) { var httpContext = FakeAuthenticatedHttpContext(); ControllerContext context = new ControllerContext( new RequestContext(httpContext, new RouteData()), controller); controller.ControllerContext = context; }
Note that the identity.Name returns “test” which is the username of an existing user in the database. If I don’t do that then the MembershipProvider.GetUser method will fail.
2. I added a couple of properties to my test class (MessageControllerTest) to make it easy for me to access the controller and view engine in all the test methods
private FakeViewEngine _fakeViewEngine; public FakeViewEngine FakeViewEngine { get { if (_fakeViewEngine == null)_fakeViewEngine = new FakeViewEngine(); return _fakeViewEngine; } } private MessageController authenticatedController; private MessageController AuthenticatedController { get { if (authenticatedController == null) { authenticatedController = new MessageController(); authenticatedController.ViewEngine = FakeViewEngine; authenticatedController.SetFakeAuthenticatedControllerContext(); } return authenticatedController; } }
3. I created my test method which is going to call a Create method in my MessageController and pass it a string.
[TestMethod] public void Create_Message_Test() { AuthenticatedController.Create(“This is a test message”); //verify Assert.AreEqual(“Json”, FakeViewEngine.ViewContext.ViewName); Assert.IsInstanceOfType(FakeViewEngine.ViewContext.ViewData,typeof(MyViewData)); Assert.IsTrue(((MyViewData)FakeViewEngine.ViewContext.ViewData).isSuccessful); Assert.IsNotNull(((MyViewData)FakeViewEngine.ViewContext.ViewData).Id); using (MyDataContext dc = new MyDataContext()) { var query = dc.Messages.Where( m => m.MessageId == ((MyViewData)FakeViewEngine.ViewContext.ViewData).Id); //verify it was added to the database Assert.AreEqual(1, query.Count()); //delete it dc.Messages.DeleteOnSubmit(query.First()); dc.SubmitChanges(); //verify it was delete Assert.AreEqual(0, query.Count()); } }
Note that in the verification block, I verify:
- The view being rendered
- The returned type of the ViewData
- Properties on the ViewData
Then I clean up the created message by deleting it from the database.
Important:
You must add your connection strings and membership definition in an app.config file in your test project. If you don’t then the default consrtuctor of your DataContext will fail to run because it looks for the connection string in the config file.
I am still wrapping my head around the concept of mocking, so any tips or advice will be appreciated.
Here are some good resources that I found during my struggle to get this to work.
ASP.NET MVC Resources
LINQ to SQL Resources
Testing and Mocking Resources
- Moq: Linq, Lambdas and Predicates applied to Mock Objects
- Moq
- Rhino Mocks
- TDD: Test-Driven Development with Visual Studio 2008 Unit Tests
Posted in
content rss

April 7th, 2008 at 3:00 pm
[…] Unit Test Linq to Sql in ASP.Net MVC with Moq […]
April 11th, 2008 at 11:32 am
I think there’s an error in the AuthenticatedController property. It seems to reference controller which does not appear to be declared. Did you mean to use authenticatedController?
April 11th, 2008 at 1:54 pm
@cannonfodder good catch, I meant to reference the private field authenticatedController. I fixed the code.