Understanding what code coverage represents, how to effectively apply it, and how to avoid its pitfalls will give you an unprecedented understanding of how unit tests may or may not be covering you from sneaky defects.

You’ve drunk the XP cool-aide and made a concerted effort to actively unit test your code. After awhile, however, you may find yourself wondering how good are those tests? Are they actually covering the code adequately? Understanding what code coverage represents, how to effectively apply it, and how to avoid its pitfalls will give you an unprecedented understanding of how those unit tests may or may not be covering you from sneaky defects. We’ll talk code based coverage and specification-based coverage and we’ll look at the tools available to gather these metrics in both the open-source and commercial worlds. Additionally, we’ll examine the notion of mutation testing and its affect on code coverage.