### Question:
DataTypeConstraintEnumerationView implements DataTypeConstraintEnumeration.View { @Override public void clear() { RemoveHelper.removeChildren(items); } @Inject  DataTypeConstraintEnumerationView(final HTMLDivElement items,
                                             final HTMLAnchorElement addIcon,
                                             final HTMLDivElement addButtonContainer); @Override void init(final DataTypeConstraintEnumeration presenter); @EventHandler("add-icon") void onAddIconClick(final ClickEvent e); @Override void clear(); @Override void addItem(final Element enumerationItem);  }### Answer:
@Test public void testClear() { final Element element = mock(Element.class); items.firstChild = element; when(items.removeChild(element)).then(a -> { items.firstChild = null; return element; }); view.clear(); verify(items).removeChild(element); }