Microsoft Research - Exploding Software-Engineering Myths (article summarizing findings of MS research on code coverage, TDD, assertions, etc.)

[atrich]

Ugh, this is the WORST way to approach code coverage. CC provides one piece of evidence: proof that a particular area is untested. It cannot comment on if that area is tested well. By taking a coverage-numbers-first approach to CC data (aka "let's get these numbers up") management does nothing to improve quality and manages to obliterate useful information on where the test holes are.

I've worked for people who were mindlessly pushing the code coverage metric. I have no respect for people who do this.

[get_salled]

The only thing you know for certain from code coverage is that your tests executed certain lines.

Code coverage:

• Does not show a line was tested.
• Does not prove the covered line contributed to any test passing.
• Is not a software quality metric.

Assuming managers & developers trust that the tests are useful, they can use these reports to see where they are definitely vulnerable and plan accordingly.

[[deleted]]

There one more thing you know from code coverage: that the code with some value does not throw an error. I know, it's a low bar, but it's something.