# Testing signals — jestjs/jest

> Canonical page: https://codevetter.com/unpack/jest/testing-signals

# Testing signals — jestjs/jest

Scanned commit 61050e9323e742539dc2360236671110e37329e6 (2026-10-02). Generated by codevetter codevetter 1.15.0 on 2026-10-02.

Source inspection; upstream code and tests were not executed.

Tests and CI definitions were inspected, not executed; no passing result or measured coverage is asserted. The repository tests itself with Jest, using package-level tests, subprocess-based e2e drivers, and separate type checks. Inspected tests exercise collection semantics, CJS dispatch, and snapshot retry persistence, with explicit runner-specific conditions. This is a bounded inventory of evidence, not exhaustive coverage.
- The main suite transforms JS/TS with babel-jest, includes root and example projects, and excludes fixture directories from direct discovery; root scripts expose focused Jest, coverage, Jasmine, VM-module, and type-test commands. — [jest.config.mjs#L37-L41](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/jest.config.mjs#L37-L41) [jest.config.mjs#L45-L81](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/jest.config.mjs#L45-L81) [package.json#L108-L126](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/package.json#L108-L126)
- Package unit tests live under __tests__, while e2e/__tests__ drivers execute fixture projects; e2e/runJest.ts launches the repository CLI with process.execPath and asserts captured subprocess results. — [CONTRIBUTING.md#L85-L95](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/CONTRIBUTING.md#L85-L95) [e2e/runJest.ts#L32-L62](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/e2e/runJest.ts#L32-L62) [e2e/runJest.ts#L121-L134](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/e2e/runJest.ts#L121-L134)
- CjsLoader unit tests stub resolution, registries, and execution, checking core-module routing, cached exports without re-execution, manual mock selection, and recursion avoidance; these tests alone do not establish real VM integration. — [packages/jest-runtime/src/internals/__tests__/CjsLoader.test.ts#L39-L89](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/packages/jest-runtime/src/internals/__tests__/CjsLoader.test.ts#L39-L89) [packages/jest-runtime/src/internals/__tests__/CjsLoader.test.ts#L93-L176](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/packages/jest-runtime/src/internals/__tests__/CjsLoader.test.ts#L93-L176)
- Collection e2e tests assert tree/JSON output, wouldRun flags, load-error reporting, no test-body execution, and parity with focused execution; test.failing parity cases explicitly skip Jasmine. — [e2e/__tests__/collectTests.test.ts#L24-L99](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/e2e/__tests__/collectTests.test.ts#L24-L99) [e2e/__tests__/collectTests.test.ts#L111-L162](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/e2e/__tests__/collectTests.test.ts#L111-L162)
- SnapshotState tests use temporary files to check retry rollback, preservation of other tests' inline/file writes, and no write after complete rollback; another test records the hint-separator ownership ambiguity. — [packages/jest-snapshot/src/__tests__/State.test.ts#L19-L49](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/packages/jest-snapshot/src/__tests__/State.test.ts#L19-L49) [packages/jest-snapshot/src/__tests__/State.test.ts#L121-L187](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/packages/jest-snapshot/src/__tests__/State.test.ts#L121-L187) [packages/jest-snapshot/src/__tests__/State.test.ts#L268-L276](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/packages/jest-snapshot/src/__tests__/State.test.ts#L268-L276)
- Retry e2e tests inspect beforeAll describe recovery, snapshot restoration, and concurrent describe retries, but the entire inspected retry suite calls skipSuiteOnJasmine. — [e2e/__tests__/testRetries.test.ts#L8-L71](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/e2e/__tests__/testRetries.test.ts#L8-L71) [e2e/__tests__/testRetries.test.ts#L529-L557](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/e2e/__tests__/testRetries.test.ts#L529-L557)
- Node CI invokes sharded Ubuntu, macOS, and Windows jobs across Node 18/20/22/24/25/26; test jobs build JavaScript and use retries with three attempts and ten-minute timeouts, while separate jobs cover declarations, lint, VM modules, Watchman, and coverage. — [.github/workflows/nodejs.yml#L31-L93](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/.github/workflows/nodejs.yml#L31-L93) [.github/workflows/nodejs.yml#L95-L127](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/.github/workflows/nodejs.yml#L95-L127) [.github/workflows/nodejs.yml#L150-L181](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/.github/workflows/nodejs.yml#L150-L181) [.github/workflows/test.yml#L14-L46](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/.github/workflows/test.yml#L14-L46)
- Coverage collection excludes bin, cli, e2e, tests, builds, and vendor paths; TypeScript integration uses a separate configuration, and CI reporting emits JSON coverage plus GitHub Actions, JUnit, silent, and summary reports. These inspected definitions do not prove execution or comprehensive behavioral coverage. — [jest.config.mjs#L13-L25](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/jest.config.mjs#L13-L25) [jest.config.ts.mjs#L11-L23](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/jest.config.ts.mjs#L11-L23) [jest.config.ci.mjs#L11-L25](https://github.com/jestjs/jest/blob/61050e9323e742539dc2360236671110e37329e6/jest.config.ci.mjs#L11-L25)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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