This page has information about standardizing the test output format. Having a standardized format would allow for simpler processing by test harnesses which collected, aggregated and presented the results from multiple kselftest tests.
It was strongly recommended, in the 2014 kernel summit, to avoid creating a new test format. In that meeting, Tim Bird recommended Jenkins output format, but Tim now recommends using the TAP format, and including integrating libtap into the kernel source tree.
While a test harness is outside the current scope of kselftest, some people may want to use one of the many (many!) test harnesses that can process TAP output: