@Test
    public void shouldTripleBulkResults() {
        long total = 0;
        final List<Tuple2<String, Long>> numbers = new ArrayList<>();
        for (long i = 0; i < 14000; i++) {
            total = total + i;
            numbers.add(new Tuple2<>("test", i));
        }

        final CombineIterator<String, Long, String, Long> combineIterator = new CombineIterator<>(new MapReduceA(), numbers.iterator());
        assertTrue(combineIterator.hasNext());
        final Tuple2<String, Long> tuple = combineIterator.next();
        assertFalse(combineIterator.hasNext());
        assertEquals("test", tuple._1());
        assertEquals(total, tuple._2().longValue());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
spark-gremlin/src/test/java/org/apache/tinkerpop/gremlin/spark/process/computer/CombineIteratorTest.java