I think he means the reverse though. It's not that a single line of code causes thousands of failures, it's that you'll never get that particular test to fail u

I think he means the reverse though. It's not that a single line of code causes thousands of failures, it's that you'll never get that particular test to fail unless pretty much everything else is failing to, ergo it's a useless test. I don't necessarily disagree with your point, just clarifying.