It gets pretty brutal when you have 10,000 tests that each have a 1/1000 chance of failing. The worst was that some tests were actually wrong and only passed d

It gets pretty brutal when you have 10,000 tests that each have a 1/1000 chance of failing. The worst was that some tests were actually wrong and only passed due to nondeterminism. Once I made the tests deterministic, I discovered they always failed. Until that point, I found those test failures very confusing, because it seemed like my efforts to improve the reliability of the tests was having no effect on them.