code: public static void assertXMLNotEqual(String err, Reader control, Reader test)
          throws SAXException, IOException {
          Diff diff = new Diff(control, test);
          assertXMLEqual(err, diff, false);
      }
docs: Assert that two XML documents are NOT similar
  @param err Message to be displayed on assertion failure
  @param control XML to be compared against
  @param test XML to be tested
  @throws SAXException
  @throws IOException