It's a nice story, but in reality (a) the code would never be delivered and (b) the criteria would be poorly designed so that something other than the desired r

It's a nice story, but in reality (a) the code would never be delivered and (b) the criteria would be poorly designed so that something other than the desired result would pass the criteria, e.g. you're required to write unit tests and the program has to pass them but the unit tests don't actually need to exercise the features of the program in a meaningful way.