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>
Three issues uncovered by the full pnpm typecheck/test/boundaries pass
and resolved here:
- core-testing was importing IEventBus / IJobQueue from core-events /
core-shared, creating two boundary violations (tooling → core) and a
build-graph cycle. Inlined the type aliases (mirroring how
RecordingTracer / RecordingLogger handle ITracer / ILogger).
recording-event-bus.test.ts replaces defineEvent() with an inline
descriptor literal so no runtime import is needed either. core-events
and core-shared are removed from core-testing dependencies.
- turbo.json: typecheck and test no longer dependsOn ^typecheck / ^build.
Each package's tsc / vitest resolves cross-package types via
node_modules independently, and dropping the topological dep avoids the
spurious cycle warning that appeared once core-testing started
importing core-events / core-shared.
- turbo.json: feature.dependencies.allow gains "feature". Cross-feature
event flow (ADR-015) requires a consumer feature to import the
publisher's event contract directly. The dangerous form (importing
the publisher's handler/use-case/repo) is still blocked by E1's
no-handler-reexport ESLint rule and the missing public exports.
- TaskConfig<"slug-string"> → TaskConfig<{ input; output }> in the gen
job task template (and the shipped send-welcome-email.task.ts) since
runtime-generated slugs aren't keys of TypedJobs['tasks'].
Adds RecordingEventBus implementing IEventBus for use in unit tests.
Validates payloads via the descriptor schema, records all publish calls,
and delivers events to subscribed handlers synchronously in subscription order.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds RecordingJobQueue implementing IJobQueue for use in unit tests.
Records all enqueue calls with taskSlug/input/options and returns
synthetic incrementing jobIds.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Each repository interface now has a contract suite under
src/__contracts__/. Both Mock and Payload implementations run the
same suite, eliminating mock-vs-real drift. Payload impls back the
contract with an in-memory stub via vi.mock('payload') + a small
buildPayloadStub helper.
Spec: §5.2, §6.4
