Cool trick to test delayed execution

test.js

    describe('when you send debug=timeout', () => {
      let fakeTimer;

      beforeEach(() => {
        lambdaParameter.queryStringParameters.debug = 'timeout';
      });

      beforeEach(() => {
        fakeTimer = sinon.useFakeTimers({
          now: Date.now(),
          shouldAdvanceTime: true,
          toFake: ['setTimeout']
        });
      });

      it('should not resolve until later', async () => {
        let executed = false;
        handler(lambdaParameter)
            .then(() => {
              executed = true;
            });

        fakeTimer.tick(59000);
        await new Promise((resolve) => setImmediate(resolve)); // allow handler to execute
        expect(executed).to.be.false;
        fakeTimer.tick(2000);
        await new Promise((resolve) => setImmediate(resolve)); // allow handler to execute
        expect(executed).to.be.true;
      });

    });