@Test
  void fetch() {
    check(Flowable.fromPublisher(create().fetch()).toList().blockingGet()).isEmpty();
    check(Flowable.fromPublisher(create("one").fetch()).toList().blockingGet()).isOf("one");
    check(Flowable.fromPublisher(create("one", "two").fetch()).toList().blockingGet()).isOf("one", "two");
    check(Flowable.fromPublisher(create("one", "two", "three").fetch()).toList().blockingGet()).isOf("one", "two", "three");
  }
Check that correct exceptions are thrown by {@link ReactiveFetcher}
criteria/common/test/org/immutables/criteria/repository/reactive/ReactiveFetcherDelegateTest.java