How is the Linux kernel tested ?

Question

How do the Linux kernel developers test their code locally and after they have it committed? Do they use some kind of unit testing, build automation? test plans?

Answer 1

I would imagine they use virtualization to do quick tests, something like QEMU, VirtualBox or Xen, and some scripts to perform configurations and automated tests.

Automated testing is probably done by trying either many random configurations or a few specific ones (if they are working with a specific issue). Linux has a lot of low-level tools (such as dmesg) to monitor and log debug data from the kernel, so I imagine that is used as well.