@Test
  public void testPowAsDouble() {
    Decimal128 val1 = new Decimal128("1.00435134913958923485982394892384",
        (short) 36);
    assertEquals(1.004366436877081d,
        val1.powAsDouble(1.00345982739817298323423423d), 0.000000000000001d);

    Decimal128 val2 = new Decimal128("1.001", (short) 36);
    assertEquals(1.0100451202102512d, val2.powAsDouble(10), 0.000000000000001d);
  }
During earlier code testing, if we found errors, test them here as regression tests.
common/src/test/org/apache/hadoop/hive/common/type/TestDecimal128.java