I find odd that there was no discussion about figuring out edge cases and testing specifically for those instead of random values. Especially for functions with

I find odd that there was no discussion about figuring out edge cases and testing specifically for those instead of random values. Especially for functions with large domains, having few hand-picked test values could give much more confidence than thousands of random values. Additionally with generated test values figuring out the validation logic becomes complex, and in complexity lies potential for bugs. If your testing code more complex than the code being tested, do you really gain that much confidence about the correctness? In comparison with hard-coded test values you can also hard-code the expected results, which can be gotten from some reference or just manually checked for correctness. Of course ideally you'd have both random fuzzing and more manually defined tests, but that is setting quite high bar.