The kernel project, for many years, lacked a formal testing setup; it was often joked that testing was the project's main reason for keeping users around. While many types of kernel testing can only be done in the presence of specific hardware, there are other parts of the kernel that could be more widely tested. Over time, though, the kernel has gained two separate testing frameworks and a growing body of automated tests to go with them. These two frameworks — kselftests and KUnit — take different approaches to the testing problem; now this patch series from Thomas Weißschuh aims to bring them together.