new_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  from __future__ import print_function, division, unicode_literals
  import unittest
  import os
  import datetime
  
  from zhihu import Question, Activity, ActType
  from zhihu.common import BeautifulSoup
  
  from test_utils import TEST_DATA_PATH
  
  
  class ActivityTest(unittest.TestCase):
      @classmethod
      def setUpClass(cls):
          url = 'http://www.zhihu.com/question/24825703'
          file_path = os.path.join(TEST_DATA_PATH, 'question.html')
          with open(file_path, 'rb') as f:
              html = f.read()
          soup = BeautifulSoup(html)
  
          cls.question = Question(url)
          cls.question._session = None
          cls.question.soup = soup
  
          act_time = datetime.datetime.fromtimestamp(1439395600)
          act_type = ActType.FOLLOW_QUESTION
          cls.activity = Activity(act_type, act_time, question=cls.question)
  
      def test_content(self):
          self.assertIs(self.question, self.activity.content)
  
subject: add test for activity