While I think writing tests for the "happy" path builds good momentum, especially for a code base with no existing tests, the real value lies in writing tests t

While I think writing tests for the "happy" path builds good momentum, especially for a code base with no existing tests, the real value lies in writing tests that exercise the edge cases. Guy Steele put it best: "I spent a lot of time worrying about edge cases. That’s something I learned from Trenchard More and his array theory for APL. His contention was that if you took care fo the edge cases then the stuff in the middle usually took care of itself."