What I am saying is that a ball of mud that passes all tests is worse than something clear that fails corner cases (genuine corner cases) because sorting that o

What I am saying is that a ball of mud that passes all tests is worse than something clear that fails corner cases (genuine corner cases) because sorting that out can be done. Whereas the ball of mud will definitely fail in the future and when it does nothing will help you apart from a complete rebuild. "It passes the tests" simply doesn't cut it.