@Test
public void testEmptyResponse() {

  RetryingReadRowsOperation underTest = createOperation();
  start(underTest);
  ReadRowsResponse response = ReadRowsResponse.getDefaultInstance();
  underTest.onMessage(response);
  verify(mockFlatRowObserver, times(0)).onNext(any(FlatRow.class));
  verify(mockClientCall, times(2)).request(eq(1));
  verify(mockResponseObserver, times(1)).onNext(same(response));
  finishOK(underTest, 0);
}