How do I test a controller to ensure that the authorize filter is applied to it with the correct role?

Question

I have a controller in the admin section of my site and it is decorated with the Authorize filter with the role set to admin.

[Authorize(Roles = "Admin")]
public class SubscriberController : Controller

This works great but I'd like to create a unit test to ensure that the filter is not removed. I've got this far, to validate that the Authorize filter is present.

        typeof(SubscriberController).Should()
            .BeDecoratedWith<AuthorizeAttribute>(
                "Subscriber controller users must be admins");

How can I validate the Roles argument? I am using Fluent Assertion 1.7.1.1.

It is possible now in Fluent Assertion v2:

    typeof(SubscriberController).Should()
        .BeDecoratedWith<AuthorizeAttribute>(a => a.Roles.Contains("Admin"),
            "Subscriber controller users must be admins");

Answer 1

Looks like that isn't possible now - Testing Arguments of Attributes

You can up this thread and ask about progress.