passing mocked parameter to mocked interface

Question

I am using nuit with moq to test my controllers.

I use a session class which has an interface and an HttpContext is injected into the constructor using ninject. like this

      public class SessionService : ISession
        {
            public HttpContext Context { get; set; }

            public SessionService(HttpContext context)
            {
                this.Context = context;
            }
    }


       public interface ISession
        {
            HttpContext Context { get; set; }
    }



   public HomeController(ISession session)
        {
            _session = session;

        }

I think in order to test the controller I have mock the HttpContext first and then pass that object into the the construtor of the mocked ISession. I have this so far

 [Test]
 public void index_returns_view()
        {
             //arrange
            var mockHttpContext = new Mock<HttpContext>();
            var mockContext = new Mock<ISession>(mockHttpContext);
            var c = new HomeController(mockContext.Object);
            //act
            var v = c.Index() as ViewResult;
            //assert
            Assert.AreEqual(v.ViewName, "Index", "Index View name incorrect");
         }

which builds but nunit returns the following error when the test is run

System.NotSupportedException : Type to mock must be an interface or an abstract or non-sealed class.

Thanks for all help.

Answer 1

Have your session take a HttpContextBase in the constructor and use that as the type of the property. You should still be able to pass a concrete HttpContext the the session in production code.

  public class SessionService : ISession 
    { 
        public HttpContextBase Context { get; set; } 

        public SessionService(HttpContextBase context) 
        { 
            this.Context = context; 
        } 
} 

Then fix your unit test by passing "mockHttpContext.Object" to the session constructor and that it mocks the HttpContextBase.

 [Test]    
 public void index_returns_view()    
        {    
             //arrange    
            var mockHttpContext = new Mock<HttpContextBase>();    
            var mockContext = new Mock<ISession>(mockHttpContext.Object);    
            var c = new HomeController(mockContext.Object);    
            //act    
            var v = c.Index() as ViewResult;    
            //assert    
            Assert.AreEqual(v.ViewName, "Index", "Index View name incorrect");    
         }