@Test
public void testTriggerType() {

  assertThat(triggerType(Trigger.natural()), is("natural"));
  assertThat(triggerType(Trigger.adhoc("foo")), is("adhoc"));
  assertThat(triggerType(Trigger.backfill("bar")), is("backfill"));
  assertThat(triggerType(Trigger.unknown("baz")), is("unknown"));
}