message: PullRefresh: fix test case
diff: @@ -102,14 +102,15 @@ describe('PullRefresh', () => {
  }
  });
  - window.pageYOffset = 100;
  + window.scrollY = 100;
  // ignore touch event when not at page top
  triggerTouch(wrapper, 'touchstart', 0, 0);
  triggerTouch(wrapper, 'touchmove', 0, 100);
  triggerTouch(wrapper, 'touchend', 0, 100);
  + expect(wrapper.vm.ceiling).to.be.false;
  - window.pageYOffset = 0;
  + window.scrollY = 0;
  triggerTouch(wrapper, 'touchmove', 0, 100);
  expect(wrapper.vm.ceiling).to.be.true;
  });
  