old_contents: """
  This file demonstrates writing tests using the unittest module. These will pass
  when you run "manage.py test".
  
  Replace this with more appropriate tests for your application.
  """
  
  from django.test import TestCase
  
  
  class SimpleTest(TestCase):
      def test_basic_addition(self):
          """
          Tests that 1 + 1 always equals 2.
          """
          self.assertEqual(1 + 1, 2)
  
new_contents: """
  This file demonstrates writing tests using the unittest module. These will pass
  when you run "manage.py test".
  
  Replace this with more appropriate tests for your application.
  """
  
  from django.test import TestCase
  from .models import Address
  
  
  class ModelsTest(TestCase):
      def test_create_address(self):
          a = Address()
          a.street = '23, Test Street'
          a.town = 'London'
          a.postcode = 'xxxxx'
          a.country = 'UK'
          a.save()
          self.assertTrue(a.id >= 0)
  
subject: Add Address model creation test case