Port test_agent and test_agent_api to Python 3

* Add neutron_lbaas.tests.nested(): contextlib.nested() for Python 3
  based on contextlib.ExitStack
* Use tests.nested() in test_agent.py and test_agent_api.py
* tests-py3.txt: add test_agent and test_agent_api

Blueprint: neutron-python3
Change-Id: Ic34fbbc41389a5fc94aaa788fc17d9701422e03b

neutron_lbaas/tests/__init__.py

@@ -0,0 +1,26 @@
+# Copyright 2016 Red Hat, Inc.
+#
+#    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 contextlib
+
+import six
+
+
+if six.PY3:
+    @contextlib.contextmanager
+    def nested(*contexts):
+        with contextlib.ExitStack() as stack:
+            yield [stack.enter_context(c) for c in contexts]
+else:
+    nested = contextlib.nested

neutron_lbaas/tests/unit/agent/test_agent.py

@@ -13,12 +13,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import contextlib
 import mock
 from oslo_config import cfg
 
 from neutron_lbaas.agent import agent
 from neutron_lbaas.tests import base
+from neutron_lbaas.tests import nested
 
 
 class TestLbaasService(base.BaseTestCase):
@@ -36,7 +36,7 @@ class TestLbaasService(base.BaseTestCase):
 
     def test_main(self):
         logging_str = 'neutron.agent.common.config.setup_logging'
-        with contextlib.nested(
+        with nested(
             mock.patch(logging_str),
             mock.patch.object(agent.service, 'launch'),
             mock.patch('sys.argv'),

neutron_lbaas/tests/unit/agent/test_agent_api.py

@@ -13,12 +13,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import contextlib
 import copy
 import mock
 
 from neutron_lbaas.agent import agent_api as api
 from neutron_lbaas.tests import base
+from neutron_lbaas.tests import nested
 
 
 class TestApiCache(base.BaseTestCase):
@@ -37,7 +37,7 @@ class TestApiCache(base.BaseTestCase):
         if method in add_host:
             expected_kwargs['host'] = self.api.host
 
-        with contextlib.nested(
+        with nested(
             mock.patch.object(self.api.client, 'call'),
             mock.patch.object(self.api.client, 'prepare'),
         ) as (

tests-py3.txt

@@ -1,3 +1,8 @@
+# Use "$" in the regex to not run
+# neutron_lbaas.tests.unit.agent.test_agent_manager which doesn't pass on
+# Python 3 yet
+neutron_lbaas.tests.unit.agent.test_agent$
+neutron_lbaas.tests.unit.agent.test_agent_api
 neutron_lbaas.tests.unit.common.cert_manager.barbican_auth.test_barbican_acl
 neutron_lbaas.tests.unit.common.cert_manager.test_barbican
 neutron_lbaas.tests.unit.common.cert_manager.test_local