@Test
  public void testMultiKeyDoubleShortString() throws HiveException {
    short s = 2;
    testMultiKey(
        "sum",
        new FakeVectorRowBatchFromObjectIterables(
            2,
            new String[] {"double", "smallint", "string", "double"},
            Arrays.asList(new Object[]{null,  1.0, 1.0,  null,  2.0,  2.0, null}),
            Arrays.asList(new Object[]{null,  s,     s,  null,    s,    s, null}),
            Arrays.asList(new Object[]{ "A", "A",  "A",   "C", null, null,  "A"}),
            Arrays.asList(new Object[]{1.0,  2.0,  4.0,   8.0, 16.0, 32.0,  64.0})),
        buildHashMap(
            Arrays.asList( 1.0,    s,  "A"), 6.0,
            Arrays.asList(null,  null, "C"), 8.0,
            Arrays.asList( 2.0,    s, null), 48.0,
            Arrays.asList(null, null,  "A"), 65.0));
  }
Unit test for the vectorized GROUP BY operator.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorGroupByOperator.java