Add common plugin framework.

For blueprint novaplugins.

It turns out that most of the plugin framework applies equally well
to other projects, so it's going into Nova via common so that
other projects can pull it in with a minimum of fuss.

Change-Id: Ia4455a8ca0b8c1c3e4b0b9647e8cacaf0a47c914

1 files changed, 92 insertions, 0 deletions

diff --git a/tests/unit/plugin/test_callback_plugin.py b/tests/unit/plugin/test_callback_plugin.py
new file mode 100644
index 0000000..a950392
--- /dev/null
+++ b/tests/unit/plugin/test_callback_plugin.py
@@ -0,0 +1,92 @@
+# Copyright 2012 OpenStack LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import pkg_resources
+
+from openstack.common.notifier import api as notifier_api
+from openstack.common.plugin import callbackplugin
+from openstack.common.plugin import pluginmanager
+from tests import utils as test_utils
+
+userdatastring = "magic user data string"
+
+
+class TestCBP(callbackplugin.CallbackPlugin):
+
+    def callback1(self, context, message, userdata):
+        self.callback1count += 1
+
+    def callback2(self, context, message, userdata):
+        self.callback2count += 1
+
+    def callback3(self, context, message, userdata):
+        self.callback3count += 1
+        self.userdata = userdata
+
+    def __init__(self, service_name):
+        super(TestCBP, self).__init__(service_name)
+        self.callback1count = 0
+        self.callback2count = 0
+        self.callback3count = 0
+
+        self._add_callback(self.callback1, 'type1', None)
+        self._add_callback(self.callback2, 'type1', None)
+        self._add_callback(self.callback3, 'type2', 'magic user data string')
+
+
+class CallbackTestCase(test_utils.BaseTestCase):
+    """Tests for the callback plugin convenience class"""
+
+    def test_callback_plugin_subclass(self):
+
+        class MockEntrypoint(pkg_resources.EntryPoint):
+            def load(self):
+                return TestCBP
+
+        def mock_iter_entry_points(_t):
+            return [MockEntrypoint("fake", "fake", ["fake"])]
+
+        self.stubs.Set(pkg_resources, 'iter_entry_points',
+                mock_iter_entry_points)
+
+        plugmgr = pluginmanager.PluginManager("testproject", "testservice")
+        plugmgr.load_plugins()
+        self.assertEqual(len(plugmgr.plugins), 1)
+        plugin = plugmgr.plugins[0]
+        self.assertEqual(len(plugin.notifiers), 1)
+
+        notifier_api.notify('contextarg', 'publisher_id', 'type1',
+                            notifier_api.WARN, dict(a=3))
+
+        self.assertEqual(plugin.callback1count, 1)
+        self.assertEqual(plugin.callback2count, 1)
+        self.assertEqual(plugin.callback3count, 0)
+
+        notifier_api.notify('contextarg', 'publisher_id', 'type2',
+                            notifier_api.WARN, dict(a=3))
+
+        self.assertEqual(plugin.callback1count, 1)
+        self.assertEqual(plugin.callback2count, 1)
+        self.assertEqual(plugin.callback3count, 1)
+        self.assertEqual(plugin.userdata, userdatastring)
+
+        plugin._remove_callback(plugin.callback1)
+
+        notifier_api.notify('contextarg', 'publisher_id', 'type1',
+                            notifier_api.WARN, dict(a=3))
+
+        self.assertEqual(plugin.callback1count, 1)
+        self.assertEqual(plugin.callback2count, 2)
+        self.assertEqual(plugin.callback3count, 1)