Comment by john-tells-all

Yes. And, a bad test -- that passes because it's defined to pass -- is _much worse_ than no test at all. It makes you think an edge case is "covered" with a meaningful check.

Worse: once you have one "bad apple" in your pile of tests, it decreases trust in the _whole batch of tests_. Each time a test passes, you have to think if it's a bad test...