Property
What it is
Generative testing via fast-check. 'For all inputs in domain D, predicate P holds.' Failures shrink to the smallest counterexample.
When to use it
Parsers, matchers, encoders/decoders, normalisers, validators.
Example gates
route-manifest-property — found a real bug (root-page strip) on first run.
See also
- The pyramid — where this mode sits relative to the others
- Writing a gate — how to scaffold a new gate in this mode
- Decision tree — "I just wrote feature X — what tests do I owe?"