If you have fully defined what your software will do up front, then you are finished when have made it do what you said it would. Safety critical software is u

If you have fully defined what your software will do up front, then you are finished when have made it do what you said it would. Safety critical software is usually designed, built and tested to the V-model. When done properly every piece of logic/code can be traced back to a requirement through all steps and phases of development and testing. There is no "move fast and break things" in the safety instrumented field, the engineering hours per byte/instruction delivered would absolutely flabbergast most software devs, by many orders of magnitude.