[$] How many kernel test frameworks?

The kernel self-test framework (kselftest) has been a part of the kernel for some time now; a relatively recent proposal for a kernel unit-testing framework, called KUnit, has left some wondering why both exist. In a lengthy discussion thread about KUnit, the justification for adding another testing framework to the kernel was debated. While there are different use cases for kselftest and KUnit, there was concern about fragmenting the kernel-testing landscape.