alt Hacker News> Most extensive test suites are exactly production scars: every time you have a bug or a regression, you write a test that confirms correct behaviour.
If you can be 100% guaranteed that there indeed is a test for every occurred bug. Sometimes maintainers are not so strict about it.
And some programmers are so good that some issues are self-explanatory and they write good code to note a thing but don't write a test, because implementing the test is more expensive.
> And some programmers are so good that some issues are self-explanatory and they write good code to note a thing but don't write a test, because implementing the test is more expensive.
You don't write a test (just) to verify that your change fixed the issue, but to ensure it doesn't regress in the future after an unrelated refactor.