@Test(expected = OperationException.class)
public void testMissingField() throws Throwable {

  GeoIpOperation op = setup(Arrays.asList(GeoProperty.LOCATION), true);
  DummpyMapEvent devent = spy(new DummpyMapEvent());
  doThrow(FieldNotFoundException.class).when(devent).getFieldAsString("ip_address");
  InternalEvent ievent = new InternalEvent("", null, 0);
  ievent.setEventObj(devent);
  op.perform(ievent);
}