new_contents: from django.test import TestCase
  
  from tickets.tests.factories import UserFactory, TicketFactory
  
  
  class TicketTestCase(TestCase):
      def test_model(self):
          obj = TicketFactory()
          self.assertTrue(obj.pk)
  
      def test_is_closed(self):
          obj = TicketFactory()
          self.assertFalse(obj.is_closed())
          obj.status = 4
          self.assertTrue(obj.is_closed())
  
  
subject: add test for Ticket model