property-based-testing

Guidance for property-based testing across languages and smart contracts. Use this skill proactively during development when you encounter patterns where PBT provides stronger coverage than example-based tests. Invoke this skill when you detect: Priority by pattern: Do NOT use this skill for: Strength hierarchy (weakest to strongest): No Exception → Type Preservation → Invariant → Idempotence → Roundtrip Based on the current task, read the appropriate section: When you detect a high-value pattern while writing tests, offer PBT as an option : "I notice encode_message / decode_message is a serialization pair. Property-based testing with a roundtrip property would provide stronger coverage than example tests. Want me to use that approach?" If codebase already uses a PBT library (Hypothesis, fast-check, proptest, Echidna), be more direct: "This codebase uses Hypothesis. I'll write property-based tests for this serialization pair using a roundtrip property." If user declines , write good example-based tests without further prompting. Do not accept these shortcuts: - Detects high-value PBT patterns automatically: serialization pairs, parsers, validators, normalization, data structures, algorithms, and smart contract state invariants - Provides a property catalog with 10 core patterns (roundtrip, idempotence, invariant, commutativity, associativity, identity, inverse, oracle,...