I’m currently working on my first ASP.NET MVC project. Naturally, I’m writing a good number of unit tests. I ran into a problem tonight with mocking Controller.User. Thankfully, someone at Stack Overflow had already asked a question about this. I took Bruno Reis’ answer:

    var principal = new Moq.Mock<IPrincipal>();
    // ... mock IPrincipal as you wish
    var httpContext = new Moq.Mock<HttpContextBase>();
    httpContext.Setup(x => x.User).Returns(principal.Object);
    // ... mock other httpContext's properties, methods, as needed
    var reqContext = new RequestContext(httpContext.Object, new RouteData());
    // now create the controller:
    var controller = new MyController();
    controller.ControllerContext =
        new ControllerContext(reqContext, controller);

and I rewrote it using NUnit.Mocks and wrapped it into an implementation of HttpContextBase:

    /// <summary>
    /// A mock <see cref="HttpContextBase"/> that implements <see cref="HttpContextBase.User"/>.
    /// </summary>
    public class MockHttpContext : HttpContextBase
        private IPrincipal _user;
        public MockHttpContext()
            DynamicMock identity = new DynamicMock(typeof (IIdentity));
            identity.ExpectAndReturn("get_Name", "testUser");
            DynamicMock user = new DynamicMock(typeof (IPrincipal));
            user.ExpectAndReturn("get_Identity", identity.MockInstance);
            _user = (IPrincipal) user.MockInstance;
        public override IPrincipal User
            get { return _user; }
            set { _user = value; }

Now mocking Controller.User is as easy as this:

    // create an instance of RequestContext using MockHttpContext.
    RequestContext requestContext =
        new RequestContext(new MockHttpContext(), new RouteData());
    // initialize the controller's ControllerContext
    _controller.ControllerContext = new ControllerContext(requestContext, _controller);