public HashMap<Object, Object> buildHashMap(Object... pairs) {
    HashMap<Object, Object> map = new HashMap<Object, Object>();
    for(int i = 0; i < pairs.length; i += 2) {
      map.put(pairs[i], pairs[i+1]);
    }
    return map;
  }
Unit test for the vectorized GROUP BY operator.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorGroupByOperator.java