> Are you saying once a program passes a test, we should stop using that test? No. I'm saying that programs have to be proven correct. Then you can use tests t

> Are you saying once a program passes a test, we should stop using that test? No. I'm saying that programs have to be proven correct. Then you can use tests to rule out other pesky problems that have nothing to do with your design being incorrect. (For example, you could prove a program correct on paper, then transcribe it incorrectly to a computer. It has happened to me before.) > These are corner cases in the concept of user input “undefined” and “null” aren't special cases in the concept of user input - they're special cases in languages that happen to have “undefined” and “null”. Octal numeric literals aren't special cases in the concept of number - they're special cases in languages where octal literals begin with the prefix “0”, rather than something more sensible like “0o”. Failing to distinguish between escaped and unescaped strings is also a language problem - they should have different types! The list goes on.