I've heard "tests are documentation" a lot, and even said it without thinkibg much myself. It sounds good, and I definitely like the idea of it, but I'm not sure it's true. Here's my thinking:

- I've never tried to understand a code base by looking at the tlunit tests first. They often require more in depth understanding (due to things like monkeypatching) than just reading the code. I haven't seen anyone else attempt this either.

- Good documentation is good as far as it aids understanding. This might be a side effect of tests, but I don't think it's their goal. A good test will catch breaks in behaviour, I'd never trade completeness for readability in tests, in docs it's the reverse.

So I think maybe, unit tests are just tests? They can be part of your documentation, but calling them documentation in and of themselves I think is maybe just a category error?