Emad Ibrahim / ASP.NET MVC, Testing / .net, ASP.NET, ASP.NET MVC, LINQ, mocking, moq, mvc, Testing, unit testing /

Unit Test Linq to Sql in ASP.Net MVC with Moq

Apr 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; }

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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; }

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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)

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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; } }

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 _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,

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[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

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 typeof(MyViewData));
Assert.IsTrue(((MyViewData)FakeViewEngine.ViewContext

.ViewData).isSuccessful); Assert.IsNotNull(((MyViewData)FakeViewEngine

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 .ViewData).isSuccessful);
Assert.IsNotNull(((MyViewData)FakeViewEngine

.ViewContext.ViewData).Id); using (MyDataContext dc = new MyDataContext()) { var query = dc.Messages.Where( m => m.MessageId == ((MyViewData)FakeViewEngine

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 .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()); } }

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 .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

Being Ignorant with LINQ to SQL

Unit Test Linq to Sql in ASP.Net MVC with Moq

ASP.NET MVC Resources

LINQ to SQL Resources

Testing and Mocking Resources