[irjustin]

> The only reason why this product is still surviving and still works is due to literally millions of tests!

Personally I consider this a good thing. It's a sign of a really mature codebase where lots of edge cases are known + accounted for.

Even if the underlying code was really well written, simply the number of edge cases hamstring any "quick hacks".

Complex, runs reliably, easy to hack - Pick two

[maxbond]

Tests are great, but relying on them in this way is like relying on a net to catch you without wearing a harness. It's a good thing if your last line of defense is reliable enough to catch you. But if you're relying on it, it's not a last line of defense, it's the only one.

You should be able to work on software because you understand how it works and what the ramifications of a given change are. Tests and code reviews provide redundancy. But here, they aren't providing redundancy, they're bearing the load.

What provides redundancy if tests are missing, broken, or misinterpreted? Have you ever fixed a bug, gone to write a test for it - and found the test already exists but passed spuriously?