@Test
public void testValidISO8601Ds() throws FieldNotFoundException {

  InternalEvent ievent = new InternalEvent("foo", null, 1);
  DummyStringEvent devent = spy(new DummyStringEvent(""));
  ievent.setEventObj(devent);
  doReturn("2020-05-04T10:45:01Z").when(devent).getFieldAsString("foo");
  TimeOperation op = new TimeOperation("foo", TimeFieldType.ISO8601);
  op.perform(ievent);
  assertEquals(1588589101000l, ievent.getEventTime());
}