I've been working on a 1-man project with maybe 5% test coverage, just for some critical libraries that I ended up refactoring a few times. There's actually one

I've been working on a 1-man project with maybe 5% test coverage, just for some critical libraries that I ended up refactoring a few times. There's actually one little library that has 100% test coverage and super detailed error messages, because that's where many of the bugs seemed to happen. I also have a simple integration test that just clicks through everything and makes sure nothing crashes. Not having a lot of tests can be painful. Especially when you're learning new languages or frameworks, you almost always want to go back and rewrite some code (or just reorganize it into different files), and it's really nice to have tests when you do that. So sometimes that gives me the motivation to start writing up a bunch of tests, and then after that I dive in and refactor everything.