Add a fixture for dealing with mock patching.

Quantum uses a pattern all over their test base, which can be
collapsed down into a simple re-usable fixture.

Change-Id: I5944505ce44ce8b79a685c3ea392f001307b5319

openstack/common/fixture/mockpatch.py

@@ -0,0 +1,51 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# Copyright 2013 Hewlett-Packard Development Company, L.P.
+# 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 fixtures
+import mock
+
+
+class PatchObject(fixtures.Fixture):
+    """Deal with code around mock."""
+
+    def __init__(self, obj, attr, **kwargs):
+        self.obj = obj
+        self.attr = attr
+        self.kwargs = kwargs
+
+    def setUp(self):
+        super(PatchObject, self).setUp()
+        _p = mock.patch.object(self.obj, self.attr, **self.kwargs)
+        self.mock = _p.start()
+        self.addCleanup(_p.stop)
+
+
+class Patch(fixtures.Fixture):
+
+    """Deal with code around mock.patch."""
+
+    def __init__(self, obj, **kwargs):
+        self.obj = obj
+        self.kwargs = kwargs
+
+    def setUp(self):
+        super(Patch, self).setUp()
+        _p = mock.patch(self.obj, **self.kwargs)
+        self.mock = _p.start()
+        self.addCleanup(_p.stop)