I think you and I don't share what is a "test". Are you thinking about unit tests? I'm thinking about unit tests, smoke tests, integration tests, e2e tests, fun

I think you and I don't share what is a "test". Are you thinking about unit tests? I'm thinking about unit tests, smoke tests, integration tests, e2e tests, functional tests, manual QA tests and probably even "the-product-works-as-expected-as-I-can-see-from-the-amazon-reviews-of-our-clients tests". I agree with your point of view in general, but "having tests" doesn't mean "having great tests". If I rewrite my code and give the binary to our clients and they don't see any difference or bug, well, that means the rewrite passed the ultimate test. In fact, the percentage of our clients that care about implementation details (such as PL) is precisely 0%.