The test run that didn't hang
The first run of a new test suite did not finish in ten minutes and I wrote down that the tests hung. Nothing had hung.
It said it worked
Green, 200, saved, “already handled” — and wrong. No error anywhere to go on.
The first run of the booking tests didn't finish in ten minutes, so I wrote down that the tests hung. A day later I corrected the entry: nothing had hung. A stuck build lock, plus my own interrupted runs piling up behind it, made every run slow. Run on its own, the 32 booking tests take about 8 seconds, and the whole server suite about a minute.
The correction matters more than the fix. I had recorded a cause I hadn't checked, and the next person to read it, probably me, would have gone looking for a deadlock that doesn't exist. Now the first thing I check on a slow run is the build lock and whatever is still running from earlier, before I touch the tests.