Presumably you also have other tests that you run the code on too, that are not sent to the candidates right? That would save some time, say if the code passes

Presumably you also have other tests that you run the code on too, that are not sent to the candidates right? That would save some time, say if the code passes all 10 tests sent to the person, and fails all 20 tests that you keep for yourself, then that person's resume would go in the trashbin with little time wasted.