@Test
  public void testSumLongNulls () throws HiveException {
    testAggregateLongAggregate(
        "sum",
        2,
        Arrays.asList(new Long[]{null}),
        null);
    testAggregateLongAggregate(
        "sum",
        2,
        Arrays.asList(new Long[]{null, null, null}),
        null);
    testAggregateLongAggregate(
        "sum",
        2,
        Arrays.asList(new Long[]{null,5L,7L,19L}),
        5L + 7L + 19L);
    testAggregateLongAggregate(
        "sum",
        2,
        Arrays.asList(new Long[]{13L,null,7L,19L}),
        13L + 7L + 19L);
  }
Unit test for the vectorized GROUP BY operator.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorGroupByOperator.java