Often when I speak to development teams about their technical debt, one of the issues they highlight is lack of unit test coverage. “We only have 30% coverage, so we’re hoping to set aside some time next sprint to get more tests in place. Our latest work all has 100% coverage, but there’s a lot of code from way-back-when which is completely lacking in tests”.
This seems to me to misunderstand the purpose of unit testing. I can see how this misunderstanding comes about: there is a general acceptance that tests are good, and that a high level of test coverage is good, therefore increasing coverage must be a worthwhile thing. Right?
Continue reading TDD: When Not To Unit Test