How to write a test so you would remember what it does in a year from now? How to write selective tests with different inputs? What is test? How to subclass tests cases and yet maintain control on which tests would run? How to extend or to filter inputs used in parent classes? Are you a tiny bit intrigued now? :)
This is not another talk about how to test, but how to organize your tests so they were maintainable. I will be using nose framework as an example, however main ideas should be applicable to any other framework you choose. Explaining how some parts of code works I would have to briefly touch some advanced python topics, although I will provide need-to-know basics there, so people with any level of python knowledge could enjoy the ride.