[Bug]: testTimeout in a project config is accepted but never applied #16510

Version

30.5.2

Steps to reproduce

Minimal reproduction: https://github.com/MoogyG/jest-project-testtimeout-repro (npm ci && npm test).

Its only dependency is [email protected], and its whole Jest setup is these two files:

// jest.config.js
module.exports = {
  projects: [{ displayName: 'a', rootDir: '<rootDir>/a', testTimeout: 30000 }],
};

// a/slow.test.js
test('waits 6 s', () => new Promise((resolve) => setTimeout(resolve, 6000)));

Run npx jest.

Expected behavior

The test passes: the project sets testTimeout: 30000, and the test takes 6 s.

Actual behavior

The test fails with the default timeout:

thrown: "Exceeded timeout of 5000 ms for a test.

npx jest --showConfig shows configs[0].testTimeout: 30000 and no globalConfig.testTimeout, so the option is accepted and normalized, but nothing reads it. A beforeAll hook that takes 6 s fails the same way ("Exceeded timeout of 5000 ms for a hook").

Moving testTimeout: 30000 to the top level of jest.config.js makes the test pass.

Additional context

jest-circus only reads the global value, in packages/jest-circus/src/legacy-code-todo-rewrite/jestAdapterInit.ts:

if (globalConfig.testTimeout) {
  getRunnerState().testTimeout = globalConfig.testTimeout;
}

config.testTimeout (the project value) is not read anywhere in jest-circus or jest-runner.

Related:

• testTimeout config not working in projects #9696 and Config 'testTimeout' not working inside 'projects' config #9759 reported this bug. Both were closed as not planned by the stale bot and locked, so I'm opening a new issue as the bot suggests.
• add missing testtimeout to intialprojectoptions #14697 (shipped in Jest 30) added testTimeout to the project options. It removed the "Unknown option" warning ([Bug]: Unknown option testTimeout validation warning when used in project specific config  #14513), but did not make the project value take effect.

Environment

System:
  OS: macOS 26.6.2
  CPU: (10) arm64 Apple M4
Binaries:
  Node: 24.22.0
  npm: 11.19.1
npmPackages:
  jest: ^30.5.2 => 30.5.2