⏰ Timers

Creating tests that interact with time involve doing some advanced operations with your test runner.

Jest Documentation: Timer Mocks

Examples

Cron

This example demonstrates how use the test runner in combination with mock timers through directly using the scheduler.

In order to test your own logic using the scheduler, you will have to attach spies differently.

// swap to fake timers
jest.useFakeTimers();

const spy = jest.fn();

// boot the test app
const app = await testRunner.run(({ scheduler }) => {

  //
  scheduler.cron({
    exec: spy,
    schedule: CronExpression.EVERY_MINUTE,
  });
});

// AFTER app is booted - time travel by an hour
jest.advanceTimersByTime(60 * 60 * 1000);
expect(spy).toHaveBeenCalledTimes(60);

// swap back to real timers
jest.useRealTimers();

// explicit app teardown (will auto stop schedules)
await app.teardown();