Use a given default for getting a preference

common/djangoapps/user_api/models.py

@@ -24,15 +24,15 @@ class UserPreference(models.Model):
         user_pref.save()
 
     @classmethod
-    def get_preference(cls, user, preference_key):
+    def get_preference(cls, user, preference_key, default=None):
         """
         Gets the user preference value for a given key
 
-        Returns None if there isn't a preference for the given key
+        Returns the given default if there isn't a preference for the given key
         """
 
         try:
             user_pref = cls.objects.get(user=user, key=preference_key)
             return user_pref.value
         except cls.DoesNotExist:
-            return None
+            return default

common/djangoapps/user_api/tests/test_views.py

@@ -83,6 +83,10 @@ class ApiTestCase(TestCase):
         """Assert that the given response has the status code 403"""
         self.assertEqual(response.status_code, 403)
 
+    def assertHttpBadRequest(self, response):
+        """Assert that the given response has the status code 403"""
+        self.assertEqual(response.status_code, 400)
+
     def assertHttpMethodNotAllowed(self, response):
         """Assert that the given response has the status code 405"""
         self.assertEqual(response.status_code, 405)
@@ -358,7 +362,7 @@ class UserPreferenceViewSetTest(UserApiTestCase):
         )
 
 
-class TestLanguageSetting(TestCase):
+class TestLanguageSetting(ApiTestCase):
     """
     Test setting languages
     """
@@ -369,7 +373,7 @@ class TestLanguageSetting(TestCase):
         lang = 'en'
         response = self.client.post(reverse('user_api_set_language'), {'language': lang})
 
-        self.assertEqual(response.status_code, 200)
+        self.assertHttpOK(response)
         user_pref = UserPreference.get_preference(user, LANGUAGE_KEY)
         self.assertEqual(user_pref, lang)
 
@@ -379,6 +383,6 @@ class TestLanguageSetting(TestCase):
 
         response = self.client.post(reverse('user_api_set_language'))
 
-        self.assertEqual(response.status_code, 400)
+        self.assertHttpBadRequest(response)
 
         self.assertIsNone(UserPreference.get_preference(user, LANGUAGE_KEY))