Presumably there are some sort of automated tests though. If those are working well enough to find bugs there's probably no need for "pure" unit tests (which I

Presumably there are some sort of automated tests though. If those are working well enough to find bugs there's probably no need for "pure" unit tests (which I normally write because of performance and reliability issues that plague automated tests running at a higher level). It makes sense that kernel OS code would be more suitable to such higher level testing, given it typically doesn't have expensive/slow dependencies on external resources out of its control.