@Test
  public void testTimestampKeyTypeAggregate() throws HiveException {
    testKeyTypeAggregate(
        "sum",
        new FakeVectorRowBatchFromObjectIterables(
            2,
            new String[] {"timestamp", "bigint"},
            Arrays.asList(new Object[]{new Timestamp(1),null, new Timestamp(1), null}),
            Arrays.asList(new Object[]{13L,null,7L, 19L})),
        buildHashMap(new Timestamp(1), 20L, null, 19L));
  }
Unit test for the vectorized GROUP BY operator.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorGroupByOperator.java