Moq: Unable to cast to interface
earlier today I asked this question . So since moq creates it's own class from an interface I wasn't able to cast it to a different class. So it got me wondering what if I created a ICustomPrincipal and tried to cast to that. This is how my mocks look: var MockHttpContext = new Mock<HttpContextBase>(); var MockPrincipal = new Mock<ICustomPrincipal>(); MockHttpContext.SetupGet(h => h.User).Returns(MockPrincipal.Object); In the method I am trying to test the follow code gives the error(again): var user = (ICustomPrincipal)httpContext.User; The error is the following: Unable to cast object of