@Test
  public void testMinString() throws HiveException {
    testAggregateString(
        "min",
        2,
        Arrays.asList(new Object[]{"A","B","C"}),
        "A");
    testAggregateString(
        "min",
        2,
        Arrays.asList(new Object[]{"C", "B", "A"}),
        "A");
  }
Unit test for the vectorized GROUP BY operator.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorGroupByOperator.java