What kind of tests should I be conducting on an express server?

I'm using Jasmine-Node to test my express server, and would like to test all the controllers and requests/responses. However, after doing some Google searching, I have only been able to find trivial examples of TDD for node/express apps. So far I have created a test for checking if the response code is 200 and another checking if the '/' route is working. However, I can't think of other ways to implement tests. What should I be testing exactly?