### Question:
TreeList { @SuppressWarnings("unused") void selectionChanged(final TreeListItem treeListItem) { callOnSelectionChanged(); } @Inject  TreeList(final View view); void populate(final List<TreeListItem> items); void refresh(); List<TreeListItem> getCurrentItems(); void clear(); Node getElement(); void clearSelection(); List<TreeListItem> getSelectedItems(); void setOnSelectionChanged(final Consumer<List<TreeListItem>> onSelectionChanged);  }### Answer:
@Test public void testSelectionChanged() { final TreeListItem treeListItem = mock(TreeListItem.class); doNothing().when(treeList).callOnSelectionChanged(); treeList.selectionChanged(treeListItem); verify(treeList).callOnSelectionChanged(); }