We have recently gone to XP (eXtreme Programming) here. One of the basic tenets of XP is writing unit tests before you start programming. I have unit tested for years, but have used tools such as Query Analyzer to do it.

The difference now is that the unit tests are stored off. They can be run stand-alone, or together as a set.

Has anyone come across a useful tool? Or should we write our own tests with T-SQL? Has anyone gone down this road yet?