### Question:
DataTypeListHighlightHelper { public void cleanHighlightClass() { cleanCSSClass(HIGHLIGHT); } @Inject  DataTypeListHighlightHelper(final DataTypeUtils dataTypeUtils); void init(final DataTypeList dataTypeList); void highlightLevel(final Element element); void highlight(final Element element); void cleanHighlightClass(); void cleanLevelHighlightClass(); DataTypeList getDataTypeList();  }### Answer:
@Test public void testCleanHighlightClass() { final Element element1 = mock(Element.class); final Element element2 = mock(Element.class); final NodeList<Element> elements = spy(new NodeList<>()); element1.classList = mock(DOMTokenList.class); element2.classList = mock(DOMTokenList.class); elements.length = 2; doReturn(element1).when(elements).getAt(0); doReturn(element2).when(elements).getAt(1); doReturn(elements).when(helper).querySelectorAll("." + HIGHLIGHT); helper.cleanHighlightClass(); verify(element1.classList).remove(HIGHLIGHT); verify(element2.classList).remove(HIGHLIGHT); }