Jest Mocking Moment to same time zone for tests

momentMock.js

// To mock globally in all your tests, add to setupTestFrameworkScriptFile in config:
// https://facebook.github.io/jest/docs/en/configuration.html#setuptestframeworkscriptfile-string
jest.mock('moment', () => {
  const moment = require.requireActual('moment-timezone');
  moment.tz.setDefault('America/Los_Angeles'); // Whatever timezone you want
  return moment;
});

If you're still struggling with timezones, try this https://www.npmjs.com/package/timezone-mock it saved my day.

@pimlie thank you! Your solution works

None of these worked for me. I realized this is simply the wrong approach (depending on what you need).

I ended up doing this instead:

test('test thing', () => {
  jest.useFakeTimers();
  jest.setSystemTime(new Date('2023-01-01'));
  expect(fn).toEqual(thing);
  jest.setSystemTime(new Date());
});

IMHO, it is best to avoid monkey-patching moment.