message: test(ImagePreview): fix failed test case
diff: @@ -119,6 +119,7 @@ test('function call', done => {
  test('double click', async done => {
  const instance = ImagePreview(images);
  + await later();
  const swipe = instance.$el.querySelector('.van-swipe__track');
  triggerDrag(swipe, 0, 0);
  triggerDrag(swipe, 0, 0);
  