private String makeNumericString(int length) {
    Random r = new Random();
    StringBuilder b = new StringBuilder();
    for(int i = 0; i < length; i++) {
      b.append(r.nextInt(10));
    }

    // choose a random sign
    String sign = r.nextInt(2) == 0 ? "-" : "";
    return sign + b.toString();
  }
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