public void testAggregateDecimal (
      String typeName,
      String aggregateName,
      int batchSize,
      Iterable<Object> values,
      Object expected) throws HiveException {

        @SuppressWarnings("unchecked")
        FakeVectorRowBatchFromObjectIterables fdr = new FakeVectorRowBatchFromObjectIterables(
            batchSize, new String[] {typeName}, values);
        testAggregateDecimalIterable (aggregateName, fdr, expected);
      }
Unit test for the vectorized GROUP BY operator.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorGroupByOperator.java