Many if not most tests are a waste of time (especially when the same guarantees are provided by, say, a type system). That said, automated tests catch a proble

Many if not most tests are a waste of time (especially when the same guarantees are provided by, say, a type system). That said, automated tests catch a problem that would make it to production just about weekly in my experience. If you're trying to do any kind of HA/CI/CD they're really really helpful. Beyond that, isolated "unit tests" are somewhat helpful too in my experience, but only so far as they allow you to easily run your test suite (and rarely, find bugs faster).