@Test
public void testDetachVolumeFromStoppedXenVm() throws NoSuchFieldException, IllegalAccessException {

    thrown.expect(NullPointerException.class);
    Field dedicateIdField = _detachCmdClass.getDeclaredField("id");
    dedicateIdField.setAccessible(true);
    dedicateIdField.set(detachCmd, 2L);
    _svc.detachVolumeFromVM(detachCmd);
}