property based testing Shipped
What this lens looks for
Use for parsers, serializers, data transformers, encoders/decoders, validators — anything where "for all valid inputs X, property Y holds"; platform tools: Hypothesis (Python), fast-check (TypeScript), FsCheck (.NET), jqwik (Kotlin/JVM), swift-testing parameterized (Swift)
What its verifier checks
At least one property test per data transformation function; round-trip property tested for encode/decode pairs (encode(decode(x)) == x); preservation property tested for collection operations