My beef is with the assumption that tests can fully encode the requirements - to the point where any bug would trigger a test failure. Having such a test suite

My beef is with the assumption that tests can fully encode the requirements - to the point where any bug would trigger a test failure. Having such a test suite is no simpler than having a perfect implementation of the requirements - i.e. it's probably only feasible, at all, in the simplest/ "didactic" cases. Having a perfect implementation is not bad, of course. It's just not realistic.