alt Hacker NewsI don't fully understand what you mean by accounting expects the probability of making the same mistake twice is fairly low? Double-entry bookkeeping can only tell you if the books are balanced or not. We absolutely cannot assume that the books reflect reality just because they're balanced. You don't need to mess up twice to mess up the books in terms of truthness.
Also tests and code are independent while you always affect both sides in double-entry always. Audits exist for a reason.
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9rx • yesterday at 3:54 PM
What about the concept of "high confidence" is not understandable?
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With double-entry bookkeeping, the only way an error can slip through is if you make the same error on both sides, or else they wouldn’t be balanced. A similar thing is true for testing: If you make both an error in your test and in your implementation, they can cancel out and appear to be error-free.
I don’t quite agree with that reasoning, however, because a test that fails to test the property it should test for is a very different kind of error than having an error in the implementation of that property. You don’t have to make the “same” error on both sides for an error to remain unnoticed. Compared to bookkeeping, a single random error in either the tests or the implementation is more likely to remain unnoticed.