/Hardening

name: Hardening
evals:
  manual:
    reason: "property-based tests are useful only when their properties and generators match the actual system invariant"
    falsifier: "the reviewer finds a property cannot expose the stated invariant violation or a generated counterexample is not actionable"
metadata:
  short-description: "Strengthen code tests using fast-check property-based testing and shrunk counterexamples. Use Assay for agent quality and Interceptor for UI verification."
version: 1.2.1
description: Hardens LifeOS tests via property-based testing with fast-check. USE WHEN harden, hardening, property test, property based testing, PBT, fast-check, strengthen tests, find bugs example tests miss, universal quantified claim, shrink counterexample, what bugs am I missing, test the tests. NOT FOR new feature tests (bun test directly), grading agent output (Assay), UI verification (Interceptor), finding security vulnerabilities, or building new functionality.

Hardening Skill

Hardening sharpens tests that already exist without adding new functionality: it turns the universal claim behind a set of example tests into a fast-check property, runs it across generated inputs, and shrinks any failure to the minimal counterexample.

One intent ships. Mutation testing, complexity scoring, duplication scanning, and acceptance-test mutation were once listed here as planned; none is built, and this file no longer advertises them (external review of the v7.40.4 payload, 2026-09-03: a routing table that promises unbuilt intents is the "confidently documented, never existed" class).

Ideal State

• Every property written states the universal claim behind existing example tests, runs across generated inputs drawn from the function's real input domain, and keeps the examples it sharpens.
• Every failure ends shrunk to a minimal counterexample with its seed, and ends in either a fixed bug or a corrected property.
• What hardening lands is recorded where the system reads it: a `bun-property` row in the ISA's Test Strategy, and a C/R/L Learning entry when a counterexample taught something.
• Functions that cannot carry a universal claim (impure, or no candidate shape) are left to example tests rather than forced into a property.

Intent Routing

| Intent | Trigger | File | |----------|---------|------| | PropertyTest | property test, property based testing, PBT, fast-check, universal quantified claim, shrink counterexample — pure functions, parsers, serializers, data transforms, invariants | `Intents/PropertyTest.md` |

Integration Points

• **Testing Doctrine Rule #12** — names fast-check as the property-testing primitive (`LIFEOS/DOCUMENTATION/Testing/TestingDoctrine.md`).
• **ISA format** — the `bun-property` ISC type with `property | generator | runs` columns (`LIFEOS/DOCUMENTATION/ISA/ISAFormat.md` § ISC Type Vocabulary). A `bun-property` row is a first-class assert: it counts toward every-ISC-an-assert coverage (H8) and `bunker test` runs it like any deterministic row.
• **Algorithm** — hardening is elected during verification when a run's criteria warrant property depth; spend is discovered from the work.
• **System prompt** — Verification Is the Mechanism section at top (`LIFEOS/LIFEOS_SYSTEM_PROMPT.md`).

> The Bunker CLI is maintainer-private and not in the public release; run code rows with `bun test ./<path>` and suite rows with `bun skills/Assay/Tools/EvalRunner.ts`.

Gotchas

_No skill-wide gotchas; the fast-check ones live in `Intents/PropertyTest.md` § Gotchas._

Examples

• "Property-test the slug parser" → PropertyTest → round-trip and idempotence properties in a `.property.test.ts` file at 1000 runs, a `bun-property` row in the ISA, and any failure shrunk with its seed pinned.
• "What bugs are my example tests missing?" → PropertyTest → the pure functions (parsers, serializers, transforms) that have only example coverage, listed as property-test candidates.