Using code coverage to find bugs
Yesterday, I found two bugs whilst looking at a code coverage report. I tend to think that shooting for 100% code coverage adds unnecessary overheard - often the last few percent doesn’t give you much benefit, and takes a disproportionate amount of time to reach, but it’s useful to at least understand why particular lines of code aren’t hit by your tests. Perhaps those lines are dead code, or perhaps - as was the case for me yesterday - it’s because your code is broken.