### Question:
ListViewScrollHandlingDelegate implements ScrollHandlingDelegate, AbsListView.OnScrollListener { @Override public void pageScrollDown() { if (listView != null) { final int height = listView.getHeight(); listView.smoothScrollBy(height, SCROLL_DURATION); } } ListViewScrollHandlingDelegate(
      @NonNull RequireScrollMixin requireScrollMixin, @Nullable ListView listView); @Override void startListening(); @Override void pageScrollDown(); @Override void onScrollStateChanged(AbsListView view, int scrollState); @Override void onScroll(
      AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount);  }### Answer:
@Test public void testPageScrollDown() throws Throwable { delegate.pageScrollDown(); assertThat(Shadows.shadowOf(listView).getLastSmoothScrollByDistance()).isEqualTo(50); }