Unit tests to asert that updating a contact's first and last names (but not an email) propagate to the linked user

src/registrar/tests/test_models.py

@@ -654,3 +654,50 @@ class TestUser(TestCase):
         """A new user who's neither transitioned nor invited should
         return True when tested with class method needs_identity_verification"""
         self.assertTrue(User.needs_identity_verification(self.user.email, self.user.username))
+        
+
+class TestContact(TestCase):
+
+    def setUp(self):
+        self.email = "mayor@igorville.gov"
+        self.user, _ = User.objects.get_or_create(email=self.email, first_name="Rachid", last_name="Mrad")
+        self.contact, _ = Contact.objects.get_or_create(user=self.user)
+
+    def tearDown(self):
+        super().tearDown()
+        Contact.objects.all().delete()
+        User.objects.all().delete()
+
+    def test_saving_contact_updates_user_first_last_names(self):
+        """When a contact is updated, we propagate the changes to the linked user if it exists."""
+        # User and Contact are created and linked as expected
+        self.assertEqual(self.contact.first_name, "Rachid")
+        self.assertEqual(self.contact.last_name, "Mrad")
+        self.assertEqual(self.user.first_name, "Rachid")
+        self.assertEqual(self.user.last_name, "Mrad")
+        
+        self.contact.first_name = "Joey"
+        self.contact.last_name = "Baloney"
+        self.contact.save()
+        
+        # Refresh the user object to reflect the changes made in the database
+        self.user.refresh_from_db()
+        
+        # Updating the contact's first and last names propagate to the user 
+        self.assertEqual(self.contact.first_name, "Joey")
+        self.assertEqual(self.contact.last_name, "Baloney")
+        self.assertEqual(self.user.first_name, "Joey")
+        self.assertEqual(self.user.last_name, "Baloney")
+        
+    def test_saving_contact_does_not_update_user_email(self):
+        """When a contact's email is updated, the change is not propagated to the lined user."""        
+        self.contact.email = "joey.baloney@diaperville.com"
+        self.contact.save()
+        
+        # Refresh the user object to reflect the changes made in the database
+        self.user.refresh_from_db()
+        
+        # Updating the contact's email does not propagate 
+        self.assertEqual(self.contact.email, "joey.baloney@diaperville.com")
+        self.assertEqual(self.user.email, "mayor@igorville.gov")
+