### Question:
GwtDOMHandler { public Element createElement(final String tagName) { return document.createElement(tagName); } GwtDOMHandler(final Document document); Element createElement(final String tagName); Text createTextNode(final String data); Comment createComment(final String data); CDATASection createCDATASection(final String data); ProcessingInstruction createProcessingInstruction(final String target,
                                                             final String data); Element createElementNS(final String namespaceURI,
                                   final String qualifiedName); Attr createAttributeNS(final String namespaceURI,
                                  final String qualifiedName); Attr setAttributeNS(final Node node,
                               final String namespaceURI,
                               final String qualifiedName,
                               final String value); Attr setAttributeNodeNS(final Node element,
                                   final Attr attr); static Node getNamedItem(NamedNodeMap map,
                                    String uri,
                                    String localName); Document getDocument();  }### Answer:
@Test public void testCreateElement() { Element element = mock(Element.class); when(document.createElement(eq("tag1"))).thenReturn(element); Element result = tested.createElement("tag1"); assertEquals(element, result); verify(document, times(1)).createElement(eq("tag1")); }