@Test
public void testEmptyBatchesAreNeverSent() throws Exception {

  UnaryCallable<LabeledIntList, List<Integer>> callable =
      new UnaryCallable<LabeledIntList, List<Integer>>() {
        @Override
        public ApiFuture<List<Integer>> futureCall(
            LabeledIntList request, ApiCallContext context) {
          throw new AssertionError("Should not call");
        }
      };
  underTest =
      new BatcherImpl<>(
          SQUARER_BATCHING_DESC_V2, callable, labeledIntList, batchingSettings, EXECUTOR);
  underTest.flush();
}