Avoid recursive include of DEFAULT_SETTINGS, add sanity test (#13236)

* Avoid recursive include of DEFAULT_SETTINGS, add sanity test to avoid similar surprises

* Implement review comments for more clear code order and readability

* Clarify comment about order of app name, which is last in order so that it can modify user settings

awx/main/tests/unit/test_settings.py

@@ -1,8 +1,31 @@
 from split_settings.tools import include
 
 
+LOCAL_SETTINGS = (
+    'ALLOWED_HOSTS',
+    'BROADCAST_WEBSOCKET_PORT',
+    'BROADCAST_WEBSOCKET_VERIFY_CERT',
+    'BROADCAST_WEBSOCKET_PROTOCOL',
+    'BROADCAST_WEBSOCKET_SECRET',
+    'DATABASES',
+    'DEBUG',
+    'NAMED_URL_GRAPH',
+)
+
+
 def test_postprocess_auth_basic_enabled():
     locals().update({'__file__': __file__})
 
     include('../../../settings/defaults.py', scope=locals())
     assert 'awx.api.authentication.LoggedBasicAuthentication' in locals()['REST_FRAMEWORK']['DEFAULT_AUTHENTICATION_CLASSES']
+
+
+def test_default_settings():
+    from django.conf import settings
+
+    for k in dir(settings):
+        if k not in settings.DEFAULTS_SNAPSHOT or k in LOCAL_SETTINGS:
+            continue
+        default_val = getattr(settings.default_settings, k, None)
+        snapshot_val = settings.DEFAULTS_SNAPSHOT[k]
+        assert default_val == snapshot_val, f'Setting for {k} does not match shapshot:\nsnapshot: {snapshot_val}\ndefault: {default_val}'