Unit Test for a View Attribute using Moq

Question

I am using Moq for unit testing and I would like to test for a view's attribute. In this case the Authorize attribute.

Example View Code:

[Authorize(Roles = "UserAdmin")]
public virtual ActionResult AddUser()
{
   // view logic here  
   return View();
}

So I would like to test the view attribute when I act on this view with a user that is in the role of UserAdmin and a user that is not in the role of user admin. Is there anyway to do this ?

Example Test:

[Test]
public void Index_IsInRole_Customer()
{
   // Arrange
   UserAdminController controller = _controller;
   rolesService.Setup(r => r.IsUserInRole(It.IsAny<string>(), It.IsAny<string>())).Returns(false); // return false for any role

   // Act
   var result = controller.AddUser();

   // Assert
   Assert.IsNotNull(result, "Result is null");
}

Answer 1

Attributes are just metadata on the type, so they don't do anything unless the surrounding infrastructure make them do something (or better yet: the surrounding infrastructure does something based on the information in those attributes). That's what the ASP.NET MVC framework does when it executes a request.

That is not what you do when you create and invoke a Controller Action in a unit test, so unless you want to go to great lengths to invoke the Controller Action using a ControllerActionInvoker (at which point the test ceases to be a unit test and becomes an integration test) you can't directly test the behavior implied by the attribute.

You can, however, write a unit test that verifies that the attribute correctly decorates the Controller Action:

var attributes = typeof(UserAdminController)
    .GetMethod("AddUser").GetCustomAttributes(true);
var result = attributes.OfType<AuthorizeAttribute>().Single();
Assert.AreEqual("UserAdmin", result.Roles);