public synchronized GpuDeviceInformation parseXml(String xmlContent)
      throws YarnException {
    InputSource inputSource = new InputSource(new StringReader(xmlContent));
    SAXSource source = new SAXSource(xmlReader, inputSource);
    try {
      return (GpuDeviceInformation) unmarshaller.unmarshal(source);
    } catch (JAXBException e) {
      String msg = "Failed to parse XML output of " +
          GPU_SCRIPT_REFERENCE + "!";
      LOG.error(msg, e);
      throw new YarnException(msg, e);
    }
  }
@Test
  public void testParseInvalidRootElement() throws YarnException {
    expected.expect(YarnException.class);
    GpuDeviceInformationParser parser = new GpuDeviceInformationParser();
    parser.parseXml("<nvidia_smiiiii></nvidia_smiiiii");
  }