I ran into a problem the other day with an hbm file, and the good folks at nhusers got me through it, but suggested that a unit test would've caught the problem earlier than I had.

I've never truly understood unit testing, but am beginning to see where certain things might stand to benefit from them. Alas, I'm still lost as to how to go about it.

The primary issue is that when I sit down with a class or interface in front of me, I don't know what to test, how to test it. I really need an 'Idiots guide to unit testing".

So before we start throwing code around, can anybody tell me what kinds of things you test, how you go about testing them, and what you do with the resulsts?