如何在Asp.Net MVC4中模拟HttpContext.User.Identity.Name

using Moq;
using System.Web;

public class MockHttpContext
{
    public static HttpContextBase CreateMockHttpContext(string username)
    {
        var mockIdentity = new Mock<IIdentity>();
        mockIdentity.SetupGet(x => x.Name).Returns(username);

        var mockPrincipal = new Mock<IPrincipal>();
        mockPrincipal.SetupGet(x => x.Identity).Returns(mockIdentity.Object);

        var mockHttpContext = new Mock<HttpContextBase>();
        mockHttpContext.SetupGet(x => x.User).Returns(mockPrincipal.Object);

        return mockHttpContext.Object;
    }
}

[TestClass]
public class UserControllerTests
{
    [TestMethod]
    public void TestGetUserName()
    {
        var mockHttpContext = MockHttpContext.CreateMockHttpContext("testUser");
        var controller = new UserController();
        controller.ControllerContext = new ControllerContext(mockHttpContext, new RouteData(), controller);

        var result = controller.GetUserName();

        Assert.AreEqual("testUser", result);
    }
}

using System.Web;

public class HttpContextWrapper : HttpContextBase
{
    private readonly HttpContext _httpContext;

    public HttpContextWrapper(HttpContext httpContext)
    {
        _httpContext = httpContext;
    }

    public override IPrincipal User
    {
        get { return _httpContext.User; }
    }
}

[TestClass]
public class UserControllerTests
{
    [TestMethod]
    public void TestGetUserName()
    {
        var httpContext = new HttpContext(new HttpRequest("", "http://tempuri.org", ""), new HttpResponse(new StringWriter()));
        httpContext.User = new GenericPrincipal(new GenericIdentity("testUser"), new string[0]);

        var controller = new UserController();
        controller.ControllerContext = new ControllerContext(new HttpContextWrapper(httpContext), new RouteData(), controller);

        var result = controller.GetUserName();

        Assert.AreEqual("testUser", result);
    }
}