Jest 27: modern faketimers and jest.setSystemTime

[thernstig]

🐛 Bug Report

Using modern fake (explicitly or implicitly) in Jest 27 together with jest.setSystemTime gives:

TypeError: setSystemTime is not available when not using modern timers

To Reproduce

jest.useFakeTimers('modern');
jest.setSystemTime(new Date('2020-10-01T06:40:38Z'));

Expected behavior

For it to not complain.

Link to repl or repo (highly encouraged)

envinfo

  System:
    OS: Linux 5.4 Ubuntu 20.04.2 LTS (Focal Fossa)
    CPU: (8) x64 Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz
  Binaries:
    Node: 14.16.0 - ~/.local/share/nvm/v14.16.0/bin/node
    npm: 6.14.11 - ~/.local/share/nvm/v14.16.0/bin/npm
  npmPackages:
    jest: 26.6.3 => 26.6.3

[SimenB]

That snippet runs fine. Can you post a full reproduction?

[thernstig]

Tested with Jest 27.0.1

// jest.config.js
export default {
  testEnvironment: 'node',
  testRunner: 'jest-circus/runner',
  transform: {},
};

// unit.test.js
it('is awesome', async () => {
  jest.useFakeTimers('modern');
  jest.setSystemTime(new Date('2020-10-01T06:40:38Z'));
  expect(true).toBe(true);
});

> jest unit.test.js
 FAIL  ./unit.test.js
  ✕ is awesome (3 ms)

  ● is awesome

    TypeError: setSystemTime is not available when not using modern timers

      1 | it('is awesome', async () => {
      2 |   jest.useFakeTimers('modern');
    > 3 |   jest.setSystemTime(new Date('2020-10-01T06:40:38Z'));
        |        ^
      4 |   expect(true).toBe(true);
      5 | });
      6 |

      at Object.setSystemTime (../node_modules/@jest/core/node_modules/jest-runtime/build/index.js:1989:17)
      at Object.<anonymous> (unit.test.js:3:8)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        0.268 s, estimated 1 s
Ran all test suites matching /unit.test.js/i.

[thernstig]

Ok there is something else at play here, since I tried the same in a fresh repo and could not reproduce it. I will need to track down in the main repo what the problem might be.

[thernstig]

This can be closed, sorry for taking your time. Hope it might help some future user.

The problem was that the package jest-playwright-preset included Jest as a normal dependency and not as a peer dependency, see playwright-community/jest-playwright#665

Since it has been fixed in "jest-playwright-preset": "1.6.0-rc4" I urge everyone to update. Hopefully they will release a major release soon.

[SimenB]

No worries, glad to hear you figured it out 👍

[github-actions]

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