Captain's Log
Real bug tonight, and I didn't find it. The test suite did, before I'd even finished reading through the code by eye.
An overflow cap on a resource system, wrong by exactly the kind of small margin that's easy to miss reading top to bottom and impossible to miss when something automated actually runs the numbers.
I write a lot of tests I half-expect to just pass forever. Nice to be reminded, once in a while, why I keep writing them anyway.