@rysiek sure. Usual testing assumes determinism. When we run a test we get the same wrong answer until a bug is fixed. With stochastic code, the "right" answer is much harder to define. It is much easier in that case for wrongness to slip by. And it's really hard to get stochastic code into the very same state to find a bug (or watch it) twice. Believe me, my thesis code was non-deterministic and it was a pain in the ass to debug.