Where do your unit tests live? Does is vary, depending on project size? Do you like a flat structure, with test files living alongside everything else? Are you a nested folders person?
I’m curious the practice of others, because I still don’t feel like I’ve found a testing directory structure that satisfies me.
In Rust, the tests usually sit right next to the source code, even in the same file. That’s partly because the compiler can just strip the tests from the final binary, and I assume partly just conventional. In Python, you usually want to keep the tests out of the final sdist/wheel, so the setup you described is probably the most common in bigger projects.