Coverage
Spot on.
I can write a test that exercises all of the code, then asserts that 1=1. I've proven that all of the code runs, but asserted no behaviour of the code whatsoever. Code coverage is, at best, a fallible proxy for good tests. Low code coverage definitely implies risk. High test coverage _might_ mean lower risk, but you should check before gaining any confidence from it.
Biting the hand that feeds IT
