when writting unit tests you may wonder, what im i actually doing? I follow the AAA pattern, well try to ;).
anyway I found this link on StackOverflow, which has a list of anti patterns for TDD (Unit testing)
http://blog.james-carr.org/2006/11/03/tdd-anti-patterns/
well worth a look, just incase you think your test is not doing what it should be.