setUp/tearDown decorator for set/clear override

Problem with recursion shows up only in full runs
of Nova for example. So split the code that sets
up the decorator and add a method to cleanup
the decorated set_override during teardown.

Also add a decorator for clear_override similar to
the one for set_override.

Added more tests for all the above.

Change-Id: Ib16af2e770e96d971aef7f5c5d48ffd781477cfe

2 files changed, 79 insertions, 2 deletions

diff --git a/oslo_messaging/conffixture.py b/oslo_messaging/conffixture.py
index 42e9d51..0d05a58 100644
--- a/oslo_messaging/conffixture.py
+++ b/oslo_messaging/conffixture.py
@@ -71,6 +71,7 @@ class ConfFixture(fixtures.Fixture):
                      '_notifier_opts',
                      'oslo_messaging_notifications')
 
+    def _setup_decorator(self):
         # Support older test cases that still use the set_override
         # with the old config key names
         def decorator_for_set_override(wrapped_function):
@@ -84,13 +85,40 @@ class ConfFixture(fixtures.Fixture):
                 elif args[0] == 'notification_topics':
                     args = ('topics', args[1], group)
                 return wrapped_function(*args, **kwargs)
+            _wrapper.wrapped = wrapped_function
             return _wrapper
 
-        self.conf.set_override = decorator_for_set_override(
-            self.conf.set_override)
+        def decorator_for_clear_override(wrapped_function):
+            @wraps(wrapped_function)
+            def _wrapper(*args, **kwargs):
+                group = 'oslo_messaging_notifications'
+                if args[0] == 'notification_driver':
+                    args = ('driver', group)
+                elif args[0] == 'notification_transport_url':
+                    args = ('transport_url', group)
+                elif args[0] == 'notification_topics':
+                    args = ('topics', group)
+                return wrapped_function(*args, **kwargs)
+            _wrapper.wrapped = wrapped_function
+            return _wrapper
+
+        if not hasattr(self.conf.set_override, 'wrapped'):
+            self.conf.set_override = decorator_for_set_override(
+                self.conf.set_override)
+        if not hasattr(self.conf.clear_override, 'wrapped'):
+            self.conf.clear_override = decorator_for_clear_override(
+                self.conf.clear_override)
+
+    def _teardown_decorator(self):
+        if hasattr(self.conf.set_override, 'wrapped'):
+            self.conf.set_override = self.conf.set_override.wrapped
+        if hasattr(self.conf.clear_override, 'wrapped'):
+            self.conf.clear_override = self.conf.clear_override.wrapped
 
     def setUp(self):
         super(ConfFixture, self).setUp()
+        self._setup_decorator()
+        self.addCleanup(self._teardown_decorator)
         self.addCleanup(self.conf.reset)
 
     @property
diff --git a/oslo_messaging/tests/test_fixture.py b/oslo_messaging/tests/test_fixture.py
index dfa78b6..2ad1117 100644
--- a/oslo_messaging/tests/test_fixture.py
+++ b/oslo_messaging/tests/test_fixture.py
@@ -12,10 +12,48 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_config import cfg
+
+from oslo_messaging import conffixture
 from oslo_messaging.tests import utils as test_utils
 
 
 class TestConfFixture(test_utils.BaseTestCase):
+
+    def test_fixture_wraps_set_override(self):
+        conf = self.messaging_conf.conf
+        self.assertIsNotNone(conf.set_override.wrapped)
+        self.messaging_conf._teardown_decorator()
+        self.assertFalse(hasattr(conf.set_override, 'wrapped'))
+
+    def test_fixture_wraps_clear_override(self):
+        conf = self.messaging_conf.conf
+        self.assertIsNotNone(conf.clear_override.wrapped)
+        self.messaging_conf._teardown_decorator()
+        self.assertFalse(hasattr(conf.clear_override, 'wrapped'))
+
+    def test_fixture_setup_teardown_decorator(self):
+        conf = cfg.ConfigOpts()
+        self.assertFalse(hasattr(conf.set_override, 'wrapped'))
+        self.assertFalse(hasattr(conf.clear_override, 'wrapped'))
+        fixture = conffixture.ConfFixture(conf)
+        self.assertFalse(hasattr(conf.set_override, 'wrapped'))
+        self.assertFalse(hasattr(conf.clear_override, 'wrapped'))
+        self.useFixture(fixture)
+        self.assertTrue(hasattr(conf.set_override, 'wrapped'))
+        self.assertTrue(hasattr(conf.clear_override, 'wrapped'))
+        fixture._teardown_decorator()
+        self.assertFalse(hasattr(conf.set_override, 'wrapped'))
+        self.assertFalse(hasattr(conf.clear_override, 'wrapped'))
+
+    def test_fixture_properties(self):
+        conf = self.messaging_conf.conf
+        self.messaging_conf.transport_driver = 'fake'
+        self.assertEqual('fake',
+                         self.messaging_conf.transport_driver)
+        self.assertEqual('fake',
+                         conf.rpc_backend)
+
     def test_old_notifications_config_override(self):
         conf = self.messaging_conf.conf
         conf.set_override(
@@ -31,3 +69,14 @@ class TestConfFixture(test_utils.BaseTestCase):
                          conf.oslo_messaging_notifications.transport_url)
         self.assertEqual(['topic1'],
                          conf.oslo_messaging_notifications.topics)
+
+        conf.clear_override("notification_driver")
+        conf.clear_override("notification_transport_url")
+        conf.clear_override("notification_topics")
+
+        self.assertEqual([],
+                         conf.oslo_messaging_notifications.driver)
+        self.assertEqual(None,
+                         conf.oslo_messaging_notifications.transport_url)
+        self.assertEqual(['notifications'],
+                         conf.oslo_messaging_notifications.topics)
\ No newline at end of file