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by tz18 1300 days ago
Yes, never. You are assuming that the implementation of all unit test cases are themselves correct (that they would fail if there was any error in the case they cover). In fact unit tests are often wrong. In that context a unit test can't even prove code incorrect, unless we know that the unit test is correct.

IMO to prove that code is correct requires a proof; a unit test can only provide evidence suggestive of correctness.
1 comments
planede 1300 days ago
Mistakes in proofs are just as probable as mistakes in exhaustive tests.

An exhaustive test is just one type of a machine verified proof.

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nicoburns 1300 days ago
> An exhaustive test is just one type of a machine verified proof.

Not entirely sure I agree with this. A proof by construction is a very different beast to empirical unit tests that only cover a subset of inputs. The equivalent would be units tests that cover every single possible input.

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planede 1300 days ago
> The equivalent would be units tests that cover every single possible input.

That's what "exhaustive" means.

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