I agree for small systems. But as they get larger you often can't keep track of every last piece simultaneously. It can also become quite involved to figure out why a relatively obscure thing happened in a particular case.
Consider something like Unreal Engine for example. It's not realistic to expect to have a full mental image of the entire system in such a case.
At least in theory the tests are supposed to cover the observable behavior that matters. So I figure if the tests pass all is well. If I still find something broken then I need to add a test case for it.
Consider something like Unreal Engine for example. It's not realistic to expect to have a full mental image of the entire system in such a case.
At least in theory the tests are supposed to cover the observable behavior that matters. So I figure if the tests pass all is well. If I still find something broken then I need to add a test case for it.