However, I didn't realize just how strong my addiction to tests had become! After a few hours of coding I couldn't keep going. The code felt wrong. I couldn't see any problems but I knew they must be there. I hadn't proved the code worked, so why would it? I started getting paranoid and my code got more and more defensive. Clearly this wasn't going to work.
So I broke down, added a t/ directory with a single test file and started back into test-driven development. The newish prove command made this particularly easy since I didn't need to add a Makefile, just:
$ prove t
Ah, much better now!