Should I test the correct action is subscribed too

I am working on a C# wpf project that uses prism. I am trying to use TDD, still new to trying to execute it properly. The issue I am having is in the constructor of a class, I subscribe to an event with a function from the class.

I have found how to verify that an event gets subscribed too, but how and more importantly should I test that the correct function is subscribed to the event? Is this going beyond unit testing and more integration testing?