old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  import unittest
  import os
  
  
  class TestDataSet(unittest.TestCase):
      """
      Class for testing the enron dataset.
      """
      def setUp(self):
          self.dataset_dir = 'enron_dataset'
  
      def tearDown(self):
          self.dataset_dir = ''
  
  
  if __name__ == '__main__':
      unittest.main()
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  import unittest
  import os
  
  
  class TestDataSet(unittest.TestCase):
      """
      Class for testing the enron dataset.
      """
      def setUp(self):
          self.dataset_dir = 'enron_dataset'
  
      def tearDown(self):
          self.dataset_dir = ''
  
      def test_dataset_folder_exist(self):
          return self.assertEqual(True, os.path.exists(self.dataset_dir))
  
  
  if __name__ == '__main__':
      unittest.main()
  
subject: Add test dataset folder exist.