Lands L3 of the agent-first coverage architecture (ADR-020) — the
mutation-testing layer. Stryker on entities + use-cases (the pure
business-logic surface) catches the third dimension of test quality:
tests that exist + execute the code but assert nothing.
Deps (root devDependencies):
- @stryker-mutator/core ^8.7.0
- @stryker-mutator/vitest-runner ^8.7.0
Shared base: packages/core-testing/stryker.base.json
- testRunner: vitest (uses each feature's vitest.config.ts)
- mutate: src/entities/** + src/application/use-cases/** (excludes
tests, factories, contracts)
- thresholds: high 90 / low 80 / break 80
- reporters: progress + html + json (reports/mutation/{index.html,
mutation.json})
- incremental mode enabled, concurrency 4, timeout 10s
- exposed via @repo/core-testing/stryker.base.json subpath export
Per-feature config: packages/auth/stryker.config.json
- 4-line file that extends the shared base
- Proof-of-concept; other features get a config when L0 unification
closes their existing test gaps
Driver: scripts/coverage/mutate.mjs (zero-dep Node ESM)
- discoverStrykerConfigs: walks packages/* and apps/* for
stryker.config.json
- Supports --filter <name>, --since <ref> (incremental), --json
- Runs Stryker per-feature via node_modules/.bin/stryker run
- Surfaces per-package pass/fail summary; exits 1 on any failure
- Tests: scripts/coverage/mutate.test.mjs (3 tests, all green)
CI: .github/workflows/mutation-nightly.yml
- Cron at 02:30 UTC + workflow_dispatch with filter input
- Uploads reports/mutation/** as artifact (30-day retention)
- On failure, opens a tracking issue labelled mutation-testing
- permissions: contents: read, issues: write
- 60-min timeout (Stryker is slow by design)
Generator: turbo gen feature now scaffolds stryker.config.json from
turbo/generators/templates/feature/stryker.config.json.hbs — new
features ship mutation-ready out of the box.
Guide: docs/guides/coverage.md L3 section fleshed out with run
syntax, config shape, base config inventory, CI behavior, and a
"what you're looking for" primer on mutation scores.
Lockfile churn: pnpm regenerated the lockfile for the new deps;
~5K-line net reduction is collateral (pnpm version drift) but
mechanical.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
6 lines
298 B
JSON
6 lines
298 B
JSON
{
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"$schema": "../../node_modules/@stryker-mutator/core/schema/stryker-schema.json",
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"_comment": "Auth feature mutation testing config. Extends @repo/core-testing/stryker.base.json (ADR-020 L3). Run with `pnpm mutate --filter @repo/auth`.",
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"extends": "@repo/core-testing/stryker.base.json"
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}
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