### Question:
XmlUtilsImpl implements XmlUtils { @Override public String getDocumentXmlString(Document document) throws TransformerException { TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, YES); StringWriter writer = new StringWriter(); transformer.transform(new DOMSource(document), new StreamResult(writer)); return writer.getBuffer().toString(); }  @Override String getDocumentXmlString(Document document); @Override Document createDocument(String rootElementName); @Override Document getDocumentFromString(String inputXml); @Override Node getOrCreateChildNode(String tagName, Node parentNode); @Override String getSubNodeText(Node parentNode, String subNodeName, boolean allowNone); @Override String getPathNodeText(Node parentNode, String path, boolean allowNone); @Override void setSubNodeText(Node filterNode, String subNodeName, String newValue); @Override String getAttributeText(Node node, String attribute); @Override Node appendChildNode(Node parentNode, String nodeName, String nodeValue); @Override String getNodeXmlString(Node node); @Override XPath getxPath(); XmlUtilsImpl setxPath(XPath xPath);  }### Answer:
@Test public void testGetDocumentXmlString() throws Exception { Assert.assertNotNull(getBasicDocument()); }