Among the metrics for measuring code quality, there is one that is especially difficult to understand, and that is test coverage. Test coverage is a dangerous metric because a really high coverage does not imply the code is well tested. As the name says, it only contemplates whether a piece of code has been triggered and hence executed by a test. For that reason, the goal of testing is basically a combination of good tests and good coverage. To summarize, it is the quality of tests that matters, the code coverage is secondary.
There are some scenarios though where code coverage is indeed a good indicator. These are when the code coverage is really low. In those, the number means a greater part of the codebase is not ...