old_contents: from django.test import TestCase
  from .models import Client, Contact
  
  
  class ClientTestCase(TestCase):
      def setUp(self):
          Client.objects.create(name='Test Starbucks', address='Felipe Ángeles 225')
          Client.objects.create(name='Test OXXO', address='Reforma 190')
  
      def test_client_names(self):
          """The objects are created and their __str__ func works"""
          starbucks = Client.objects.get(name='Test Starbucks')
          oxxo = Client.objects.get(name='Test OXXO')
          self.assertEqual(str(starbucks), 'Test Starbucks')
          self.assertEqual(str(oxxo), 'Test OXXO')
  
  
  class ContactTestCase(ClientTestCase):
      def setUp(self):
          starbucks = Client.objects.create(name='Test Starbucks', address='Felipe Ángeles 225')
          Client.objects.create(name='Test OXXO', address='Reforma 190')
  
          Contact.objects.create(
              name='Fernando',
              last_name='Lobato Meeser',
              charge='Project Owner',
              landline='4424674323',
              mobile_phone_1='2341631',
              email='lobato.meeser.fernando@hotmail.com',
              alternate_email='ferlobo93@hotmail.com',
              client=starbucks)
  
      def test_contact_name(self):
          '''
              Tests if the objects are being created in the database and their __str__ func works
          '''
          client_instance = Contact.objects.get(name='Fernando')
          self.assertEqual(str(client_instance), 'Fernando Lobato Meeser')
  
      def test_relation_contact(self):
          '''
              Test if the contact objects are correctly referecing their clients.
          '''
          client_instance = Contact.objects.get(name='Fernando')
          starbucks = Client.objects.get(name='Test Starbucks')
          self.assertEqual(client_instance.client, starbucks)
  
new_contents: from django.test import TestCase
  from .models import Client, Contact
  
  
  class ClientTestCase(TestCase):
      def setUp(self):
          Client.objects.create(name='Test Starbucks', address='Felipe Ángeles 225')
          Client.objects.create(name='Test OXXO', address='Reforma 190')
  
      def test_client_names(self):
          """The objects are created and their __str__ func works"""
          starbucks = Client.objects.get(name='Test Starbucks')
          oxxo = Client.objects.get(name='Test OXXO')
          self.assertEqual(str(starbucks), 'Test Starbucks')
          self.assertEqual(str(oxxo), 'Test OXXO')
  
  
  class ContactTestCase(ClientTestCase):
      def setUp(self):
          starbucks = Client.objects.create(name='Test Starbucks', address='Felipe Ángeles 225')
          Client.objects.create(name='Test OXXO', address='Reforma 190')
  
          Contact.objects.create(
              name='Fernando',
              last_name='Lobato Meeser',
              charge='Project Owner',
              landline='4424674323',
              mobile_phone_1='2341631',
              email='lobato.meeser.fernando@hotmail.com',
              alternate_email='ferlobo93@hotmail.com',
              client=starbucks)
  
      def test_contact_name(self):
          """Tests if the objects are being created in the database and their __str__ func works
          """
          client_instance = Contact.objects.get(name='Fernando')
          self.assertEqual(str(client_instance), 'Fernando Lobato Meeser')
  
      def test_relation_contact(self):
          """Test if the contact objects are correctly referecing their clients.
          """
          client_instance = Contact.objects.get(name='Fernando')
          starbucks = Client.objects.get(name='Test Starbucks')
          self.assertEqual(client_instance.client, starbucks)
  
subject: Change single quote docstring