> What the heck was I doing? Where was the value of this test? There was none. If the index method returns a 404, it’s because I didn’t create the damn template yet. Why would I deploy my application at this stage?
This is so, so wrong I don't even know where to start. If you work on a real-world project, you soon realize how complex and entangled the view layer can become in Rails. Controllers inheriting from non-obvious parents, including modules and helpers that implicitly require instance variables. And to add even more complexity on top of it, before and after filters (or actions since Rails 4) that can be inherited or skipped by children.
Bottom line: considering all the complexities I just enumerated, a controller test that checks the status code of a get request might not be as superfluous as it might sound, it could actually save you a lot of headaches.