When did I test enough? While code coverage is a good indicator, you still have to know how code coverage works. Today I was hunting a bug in a Markdown importer I wrote for OpenFastTrace. The class where the bug sits had a whooping 93.1% code coverage and part of that missing coverage was owed to the fact that the JaCoCo coverage tracer can’t mark code that throws exceptions as covered – even though there is a test case for it.