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