[$] A kernel unit-testing framework

For much of its history, the kernel has had little in the way of formaltesting infrastructure. It is not entirely an exaggeration to say thattesting is what the kernel community kept users around for. Over theyears, though, that situation has improved; internal features likekselftest and services like the 0day testing system have increased our testcoverage considerably. The story is unlikely to end there, though; thenext addition to the kernel's testing arsenal may be a unit-testing frameworkcalled KUnit.