### Question:
TreeListView implements TreeList.View { @Override public void add(final TreeListItem item) { treeItemsContainer.appendChild(item.getElement()); } @Inject  TreeListView(final HTMLDivElement treeItemsContainer); @Override void init(final TreeList presenter); @Override void add(final TreeListItem item); @Override void clear(); @Override HTMLElement getElement();  }### Answer:
@Test public void testAdd() { final TreeListItem item = mock(TreeListItem.class); final Node element = mock(Node.class); when(item.getElement()).thenReturn(element); listView.add(item); verify(treeItemsContainer).appendChild(element); }