function makeEvent(key, shift) {
      const event = {
        key: key,
        shiftKey: shift,
      };
      event.stopPropagation = sinon.fake();
      event.preventDefault = sinon.fake();
      return event;
    }
Make a fake event.
@param {string} key The key to use for the event.
@param {boolean} shift True if we want to emulate hitting the shift key.
   False otherwise.
@returns {Object} A fake event.