Mock User.Identity in ASP.NET Core for Unit Testing [duplicate]

Question

I am struggling to implement unit testing for action methods that incorporate User.Identity.Name functionality. The methods that I've come across fail because the properties that they suggest writing to throw 'read-only' errors (e.g. writing to HttpContext or the controller User)

I have an action method:

[Authorize]
        public async Task<ViewResult> EditProject(int projectId)
        {
            Project project = repository.Projects.FirstOrDefault(p => p.ProjectID == projectId);
            if (project != null)
            {
            //HOW DO I MOCK USER.IDENTITY.NAME FOR THIS PORTION?
                var user = await userManager.FindByNameAsync(User.Identity.Name); 
                bool owned = await checkIfUserOwnsItem(project.UserID, user);
                if (owned)
                {
                    return View(project);
                }
                else
                {
                    TempData["message"] = $"User is not authorized to view this item";
                }
             }
            return View("Index");
        }

If I want to unit test this action method, how can I mock up the User.Identity object?

[Fact]
        public async Task Can_Edit_Project()
        {
            //Arrange
            var user = new AppUser() { UserName = "JohnDoe", Id = "1" };
            Mock<IRepository> mockRepo = new Mock<IRepository>();
            mockRepo.Setup(m => m.Projects).Returns(new Project[]
            {
                new Project {ProjectID = 1, Name = "P1", UserID = "1"},
                new Project {ProjectID = 2, Name = "P2", UserID = "1"},
                new Project {ProjectID = 3, Name = "P3", UserID = "1"},
            });
            Mock<ITempDataDictionary> tempData = new Mock<ITempDataDictionary>();
            Mock<UserManager<AppUser>> userMgr = GetMockUserManager();
            //Arrange
            ProjectController controller = new ProjectController(mockRepo.Object, userMgr.Object)
            {
                TempData = tempData.Object,
            };


           //HOW WOULD I MOCK THE USER.IDENTITY.NAME HERE?
           //The example below causes two errors:
           // 1) 'Invalid setup on a non-virtual (overridable in VB) member
           //mock => mock.HttpContext
           //and 2) HttpContext does not contain a definition for IsAuthenticated
           var mock = new Mock<ControllerContext>();
           mock.SetupGet(p => p.HttpContext.User.Identity.Name).Returns(user.UserName);
          mock.SetupGet(p => p.HttpContext.Request.IsAuthenticated).Returns(true);

            //Act
            var viewResult = await controller.EditProject(2);
            Project result = viewResult.ViewData.Model as Project;

            //Assert
            Assert.Equal(2, result.ProjectID);
        }

EDIT: Making some progress by adding the code below.

var claims = new List<Claim>()
            {
                new Claim(ClaimTypes.Name, "John Doe"),
                new Claim(ClaimTypes.NameIdentifier, "1"),
                new Claim("name", "John Doe"),
            };
            var identity = new ClaimsIdentity(claims, "TestAuthType");
            var claimsPrincipal = new ClaimsPrincipal(identity);

            var mockPrincipal = new Mock<IPrincipal>();
            mockPrincipal.Setup(x => x.Identity).Returns(identity);
            mockPrincipal.Setup(x => x.IsInRole(It.IsAny<string>())).Returns(true);

            var mockHttpContext = new Mock<HttpContext>();
            mockHttpContext.Setup(m => m.User).Returns(claimsPrincipal);

The User.Identity.Name is set properly now, but the line below still returns a user = null

var user = await userManager.FindByNameAsync(User.Identity.Name);

How can I make sure my mocked UserManager can return a mocked logged in user?

Answer 1

Set your fake User through ControllerContext

var context = new ControllerContext
{
    HttpContext = new DefaultHttpContext
    {
        User = fakeUser
    }
};

// Then set it to controller before executing test
controller.ControllerContext = context;