The testing for aerospace is extremely rigorous ... For DO-178C level A (Catastrophic failure that can cause a crash or many fatal injuries) we're estimating 2 years to do MC/DC test coverage metric of a fairly basic software system that has two mechanical backups. And that's above and beyond the extensive unit tests.

The main thing that gets checked is the worst-case timing analysis for every branch condition. And there are stack monitors to monitor if the stack is growing in size.

Look at Rapita System's website for more info ... we don't use them, but they explain it well.

Wait till you hear about boeing in space.