Well, not exactly -- there's an enormous unit test suite, and most changes come with associated tests to prove correctness (tests, in turn, are deemed correct b

Well, not exactly -- there's an enormous unit test suite, and most changes come with associated tests to prove correctness (tests, in turn, are deemed correct by automatically running them on a dozen different versions of windows). Regressions still happen, of course -- we might not be testing the right thing, or we might hit an edge case where implementing something completely correctly caused an application to break that was secretly relying on one wine bug hiding another wine bug.