diff --git a/skills/tdd-criteria/SKILL.md b/skills/tdd-criteria/SKILL.md new file mode 100644 index 0000000..5f4e5c9 --- /dev/null +++ b/skills/tdd-criteria/SKILL.md @@ -0,0 +1,87 @@ +--- +name: tdd-criteria +version: 0.1.0 +description: > + TDD by default with four bright-line carve-outs. Applies before any code + change the agent didn't author this session. Triggers: "TDD", + "test-driven", "следуй TDD", "use TDD", "should I write tests", + "skip tdd", "[skip-tdd: ...]", "[test-modify: ...]", "tdd-criteria". + Cross-agent policy — no tool refs. Full rationale: + .wiki/concepts/tdd-criteria-design.md +--- + +# tdd-criteria + +> TDD by default. Skip only with a bright-line marker. Tests defend code from silent deletion; rule 4 defends tests from silent rewriting. + +## When this runs + +**At session start** — when `CLAUDE.md` contains the line `follow tdd-criteria`. + +**Before any code change** the agent didn't author this session — touching a `*.ts`, `*.js`, `*.py`, or similar source file triggers the decision algorithm below. + +**On explicit reference** — when the user says "TDD", "test-driven", "следуй TDD", "use TDD", "should I write tests", "skip tdd", "tdd-criteria", or includes `[skip-tdd: ...]` or `[test-modify: ...]` in a commit subject. + +## Default mode + +TDD by default. Skip only if one of four bright-line carve-outs matches and is marked in the commit subject. + +## Decision algorithm (8 questions, top-down) + +Walk through in order. First «yes» determines mode. All «no» → TDD by default. + +1. **Bug fix?** → TDD (red-test first) +2. **Consuming external contract** (SDK, REST API, чужая schema)? → TDD (contract-test) +3. **Security / auth / money / identifiers?** → TDD +4. **Pure logic** — function (input → output) without I/O, global state, bounded inputs? → TDD +5. **Visual / config** — CSS, layout, design tokens, `.env.example`, prompts, wiki, README? → SKIP, `[skip-tdd: visual]` +6. **Spike** — explicit POC «throwaway» in commit/PR/task subject? → SKIP, `[skip-tdd: spike]` + spike-survivor task if code survives +7. **One-shot** — migration, ETL backfill, ad-hoc cleanup, runs once? → SKIP, `[skip-tdd: oneshot]` +8. **Transit wrapper** ≤10 lines — no branching, re-export / glue? → SKIP, `[skip-tdd: wrapper]` + +(default) → TDD + +## Ironclad rules (TDD obligatory) + +1. **Bug fix** — if there's an issue / failure log / repro, write a red-test codifying the repro. Marginal cost: 5 min. Marginal benefit: regression test forever. +2. **Pure logic, bounded inputs** — no fixtures, no mocks, no setup. Test = input/output pair. Skipping is gratuitous. +3. **Third-party contract** — SDK bumps change signatures silently. Contract-test pins known input → known shape. Catches break at first install, not days later. +4. **Security / auth / money / IDs** — asymmetric blast radius: false positive ≪ false negative. TDD = insurance. + +In all four, recovery cost from silent deletion is high. The test is the only artefact that makes deletion visible. + +## Permissive carve-outs (skip + marker required) + +| # | Category | Trigger | Marker | +|---|----------|---------|--------| +| 5 | Visual / config | CSS, layout, tokens, `.env.example`, prompts, wiki | `[skip-tdd: visual]` | +| 6 | Spike | «POC, throwaway» in commit/PR/task subject | `[skip-tdd: spike]` | +| 7 | One-shot | Migration, ETL, ad-hoc cleanup; runs once | `[skip-tdd: oneshot]` | +| 8 | Wrapper | ≤10 lines, no branching, re-export / glue | `[skip-tdd: wrapper]` | + +These are **accepted-risk zones** — you accept that an agent can vandalise without immediate signal, because recovery is cheap (eyeball next render; throwaway by contract; runs once; reconstruct ≤ delete). + +## Anti-loophole + +1. **Skip without category is invalid.** One of four explicit categories required — not «other reasons». No marker = violation. +2. **Spike survivor rule.** Merged spike → same merge-commit creates `[backfill-tests-]` task. Otherwise «spike» becomes «skipped tests forever». +3. **Friction is the point.** `[skip-tdd: visual]` 50× in a design-system rework is irritating — that's the fence. Re-evaluate after ≥2 weeks, not before. +4. **Tests are append-only by default.** Modifying an assertion, deleting a test, or disabling it (`it.skip`/`xit`/`@pytest.mark.skip`/`@Disabled`) requires: + - **Marker in commit subject:** `[test-modify: : was ; is ; reason: ]` — `` and `` are **literal assertion expressions**, not paraphrased. Example: `[test-modify: validates email: was expect(isValid("a@b")).toBe(true); is expect(isValid("a@b.com")).toBe(true); reason: tightened spec to require TLD]` + - **Separate commit from impl changes.** A commit must not modify both `*.test.*` and `src/*` files (or project-equivalents). `git log --grep '\[test-modify'` must show a clean test-only audit trail. + - **Why literal was/is:** an agent forced to write the literal assertion publishes exactly what they're rewriting. «Updated to match new behaviour» hides everything — agents will use that whenever allowed. + +## Cross-agent applicability + +Pure policy — no agent-specific tool references in this body. Works on Claude, Gemini, Copilot, or any future agent. Hermes mapping: `mode: auto`, `category: software-development`, no replace-rules. + +## Out of scope + +- Does not enforce via git hooks (separate optional task: `tdd-criteria-precommit-hook`). +- Does not modify project `CLAUDE.md` (that's `project-bootstrap`'s job). +- Does not run tests. +- Does not apply rule 4 retroactively to tests written before the rule was adopted. + +## Why this exists + +Tests make behaviour an invariant; without them, code is an artefact silent-deletable by agents. AND: the test itself must be defended too (rule 4) — otherwise the contract collapses back into an artefact when the agent rewrites the failing test. Full rationale: `.wiki/concepts/tdd-criteria-design.md`. \ No newline at end of file