new_contents: #!/usr/bin/env python3
  import os
  import heutagogy
  import unittest
  import tempfile
  
  class HeutagogyTestCase(unittest.TestCase):
      def setUp(self):
          self.db_fd, heutagogy.app.config['DATABASE'] = tempfile.mkstemp()
          heutagogy.app.config['TESTING'] = True
          self.app = heutagogy.app.test_client()
          with heutagogy.app.app_context():
              heutagogy.persistence.initialize()
  
      def tearDown(self):
          os.close(self.db_fd)
          os.unlink(heutagogy.app.config['DATABASE'])
  
      def test_hello_world(self):
          res = self.app.get('/')
          assert b'Hello, world!' == res.data
  
  if __name__ == '__main__':
      unittest.main()
  
subject: Implement first test