A Success Test That Accepts Any Output Is Not a Test

Problem

A check reports success and the operation did not happen. The check is not lying about what it saw — it is reporting truthfully on a predicate that cannot distinguish success from failure, because failure output satisfies the predicate too. This is not the same bug as a missing check. A missing check is loud: nothing claims the work is done. This one is silent and worse, because it manufactures positive evidence.

Use when

Any of these, in any language: