try {
parser = (DOMParser)manager.lookup(DOMParser.ROLE);
processor = (XPathProcessor)manager.lookup(XPathProcessor.ROLE);
Document document1 = parser.parseDocument(new InputSource(new StringReader(CONTENT1)));
Document document2 = parser.parseDocument(new InputSource(new StringReader(CONTENT2)));
// 1. Test single node expression
String expr = "/test:root/test:element1";
Node node = processor.selectSingleNode(document1, expr);
assertNotNull("Must select <test:element1/> node, but got null", node);