Testing service workers

Has anyone explicitly run WPT tests for service worker optimizations? I know that it takes at least two page loads for the SW to be activated and by that time the cache will have already been warm from the previous navigation. Is a warm cache still useful? Would it be more useful to invalidate certain static resources to test the SW behavior? How could that be done?

More questions than answers for now, but look forward to hearing any experience that may be out there.