Authors property-based tests in Rust using proptest - wires the `proptest!` macro, defines strategies (`prop::collection::vec`, type-driven `any` strategies, regex-based string strategies), uses the strategy-per-value model (vs QuickCheck's per-type) for flexible composition, and exploits proptest's automatic shrinking + persistence of failed cases (regression test artifact). Use when a Rust codebase needs PBT - pairs especially well with parsers, serializers, and any function with a structured input domain.