I do. My point is that not all code is of same kind. E.g. for the case you point, I do extensive unit testing for synchronous code with inputs and output/s that

I do. My point is that not all code is of same kind. E.g. for the case you point, I do extensive unit testing for synchronous code with inputs and output/s that does significant stuff, in order to avoid breaking past things with new changes. You can check that I try to honor what I say, here: https://github.com/faragon/libsrt/blob/master/examples/stest.c https://github.com/faragon/libsrt/blob/master/examples/stest... However, there are cases where unit testing is not suitable, or it is not a guarantee, or it is an additional risk, e.g. event-driven or low level stuff, multithreaded code, etc.