This still has nothing to do with Linux. Unit testing isn't standardized in most languages. Even in Rust people have custom frameworks! The Linux Kernel does h

This still has nothing to do with Linux. Unit testing isn't standardized in most languages. Even in Rust people have custom frameworks! The Linux Kernel does have such a project doing batteries of tests. Userspace may not, but that's not a "unit test" problem. In fact it's the opposite, it's integration tests.