100% test coverage doesn’t mean your code’s bug free but it did just lead me to find and fix an issue in JavaScript Database (JSDB)¹ with a code path that wasn’t being hit that I would have otherwise missed because it was causing the relevant test to pass.
¹ JSDB is a zero-dependency, transparent, in-memory, streaming write-on-update JavaScript database for the Small Web that persists to a JavaScript transaction log (an append-only log).