I'm not very familiar with how car component software is developed, so I can't speak to that. In avionics, the software requirements are only one part of the s

I'm not very familiar with how car component software is developed, so I can't speak to that. In avionics, the software requirements are only one part of the system. There's requirements for how the hardware is to behave, and tolerances for acceptable behavior. All of these pieces are tested. The software is tested by itself in a pure software environment, and it's tested running on the specific piece of hardware that it needs to run on, and that software+hardware combination is tested in various stages of increasingly complete avionics systems, culminating in testing the entire airplane. But I was just talking about the software, where we do employ requirements, verification, testing, and "software engineering". That's only one piece of the system of course, but still a valuable piece. If the software doesn't work right by itself in an idealized environment, then it has little hope of working right when the hardware is going bonkers. And even in the idealized pure software environment, we simulate various system failures to do initial testing on how the software responds.