Just got a review copy of Pragmatic Unit Testing by the Pragmatic Programmer guys. I think I'm going to have to borrow a quote from the back for everything testing-related that I do:
You don't test a bridge by driving a single car over it right down the middle lane on a clear, calm day.The book's examples are in JUnit, but from thumbing through it, it looks like the concepts apply across the board.
I bought the original book at 40% off at Barnes and Noble a month or so ago, and am loving it. I treat myself to a chapter to start every work day.