Fixed #17895 -- Made override_settings send the setting_changed signal both when a setting is overridden and when it's restored.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17708 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/test/utils.py

@@ -167,15 +167,6 @@ def restore_template_loaders():
     delattr(loader, RESTORE_LOADERS_ATTR)
 
 
-class OverrideSettingsHolder(UserSettingsHolder):
-    """
-    A custom setting holder that sends a signal upon change.
-    """
-    def __setattr__(self, name, value):
-        UserSettingsHolder.__setattr__(self, name, value)
-        setting_changed.send(sender=self.__class__, setting=name, value=value)
-
-
 class override_settings(object):
     """
     Acts as either a decorator, or a context manager. If it's a decorator it
@@ -215,10 +206,18 @@ class override_settings(object):
         return inner
 
     def enable(self):
-        override = OverrideSettingsHolder(settings._wrapped)
+        override = UserSettingsHolder(settings._wrapped)
         for key, new_value in self.options.items():
             setattr(override, key, new_value)
         settings._wrapped = override
+        for key, new_value in self.options.items():
+            setting_changed.send(sender=settings._wrapped.__class__,
+                                 setting=key, value=new_value)
 
     def disable(self):
         settings._wrapped = self.wrapped
+        for key in self.options:
+            new_value = getattr(settings, key, None)
+            setting_changed.send(sender=settings._wrapped.__class__,
+                                 setting=key, value=new_value)
+

docs/ref/signals.txt

@@ -477,20 +477,24 @@ setting_changed
 .. data:: django.test.signals.setting_changed
    :module:
 
-Sent when some :ref:`settings are overridden <overriding-settings>` with the
+This signal is sent when the value of a setting is changed through the
 :meth:`django.test.TestCase.setting` context manager or the
 :func:`django.test.utils.override_settings` decorator/context manager.
 
+It's actually sent twice: when the new value is applied ("setup") and when the
+original value is restored ("teardown").
+
 Arguments sent with this signal:
 
 ``sender``
     The settings handler.
 
 ``setting``
-    Same as sender
+    The name of the setting.
 
 ``value``
-    The new setting value.
+    The value of the setting after the change. For settings that initially
+    don't exist, in the "teardown" phase, ``value`` is ``None``.
 
 template_rendered
 -----------------

tests/regressiontests/settings_tests/tests.py

@@ -132,6 +132,7 @@ class SettingsTests(TestCase):
         self.assertRaises(AttributeError, getattr, settings, 'TEST')
         with self.settings(TEST='override'):
             self.assertEqual(testvalue, 'override')
+        self.assertEqual(testvalue, None)
 
     @override_settings(TEST='override')
     def test_signal_callback_decorator(self):