.net c# APIController attribute testing

I want to test if my Attributes on the controller functions correctly. The attributes will allow and deny access to resources in the API methods. For a valid request it gets passed straight through the pipe for an invalid request it stops the pipe and throw an exception before the method is reached.

I am using nUnit testing for these test.

So I can test the controller, but I need to test that the attribute does its job for every controller.