final Map<String, String> namespaces = new HashMap<String, String>();
namespaces.put("g", "http://www.test.com/g");
final String expression = "//f:width";
final XPathExtractor extractor = initialiseExtractor(expression, XPathReturnType.STRING);
extractor.setNamespaces(namespaces);
assertEquals("http://www.test.com/g", extractor.getNamespaces().get("g"));
}