property-based-testing

Use when reasoning about tests that specify universal properties of code rather than specific input-output pairs: the forall(input) → property quantification, the generator/shrinker primitives that produce inputs and minimize failing cases, the four-rules-of-simple-design analog (commutativity, associativity, idempotence, round-trip, oracle, invariant), the difference between example-based tests (one input, one assertion) and property-based tests (many generated inputs, one universal claim), why property tests find bugs example tests don't, the shrinking discipline that produces minimal failing cases, and the trade-off between generator complexity and bug-finding capacity. Do NOT use for specifying one concrete behavior with one input (use example-based tests under testing-strategy), for fuzz-testing focused on crashes (use fuzz-testing), for mutation testing as a test-suite quality signal (use mutation-testing), or for model-based testing of state machines (use state-machine-modeling).