Mutation testing can help with that. With mutation testing the program is changed automatically in small ways to see if that makes a test fail. https://en.wiki

Mutation testing can help with that. With mutation testing the program is changed automatically in small ways to see if that makes a test fail. https://en.wikipedia.org/wiki/Mutation_testing https://en.wikipedia.org/wiki/Mutation_testing That said, any metric is only useful for people actually using it to improve something, and completely useless when used in an adversarial way against someone willing to game the system. Coverage is pretty useful for a programmer to see where test gaps are, and easily gamed when it's felt to be too onerous.