new_contents: # Copyright (C) 2013 Nippon Telegraph and Telephone Corporation.
  # Copyright (C) 2013 YAMAMOTO Takashi <yamamoto at valinux co jp>
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  # implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import unittest
  from nose.tools import eq_
  
  import addrconv
  
  
  class Test_hub(unittest.TestCase):
      """ Test case for ryu.lib.addrconv
      """
  
      def setUp(self):
          pass
  
      def tearDown(self):
          pass
  
      @staticmethod
      def _test_conv(conv, text_value, bin_value):
          eq_(conv.text_to_bin(text_value), bin_value)
          eq_(conv.bin_to_text(bin_value), text_value)
  
      def test_ipv4(self):
          self._test_conv(addrconv.ipv4, '127.0.0.1', '\x7f\x00\x00\x01')
          self._test_conv(addrconv.ipv4, '255.255.0.0', '\xff\xff\x00\x00')
  
      def test_ipv6(self):
          self._test_conv(addrconv.ipv6, 'ff02::1',
                          ('\xff\x02\x00\x00\x00\x00\x00\x00'
                           '\x00\x00\x00\x00\x00\x00\x00\x01'))
          self._test_conv(addrconv.ipv6, 'fe80::f00b:a4ff:fe7d:f8ea',
                          ('\xfe\x80\x00\x00\x00\x00\x00\x00'
                           '\xf0\x0b\xa4\xff\xfe\x7d\xf8\xea'))
          self._test_conv(addrconv.ipv6, '::',
                          ('\x00\x00\x00\x00\x00\x00\x00\x00'
                           '\x00\x00\x00\x00\x00\x00\x00\x00'))
  
      def test_mac(self):
          self._test_conv(addrconv.mac, 'f2:0b:a4:01:0a:23',
                          '\xf2\x0b\xa4\x01\x0a\x23')
  
subject: add a test for ryu.lib.addrconv