Extract part of PlacementFixture to placement

In nova.tests.fixtures is a PlacementFixture that peforms two roles. One
is to provide a working placement service via wsgi-intercept. The other
is to provide a working client of that service in the form of a
scheduler report client that uses appropriate headers and endpoints.

This change extracts the first role to a new fixture hosted within the
placement hierarchy and makes the second role a subclass of the first.

To make this work nicely, existing placement fixtures (in fixtures.py),
used solely for the gabbi tests are moved into a new directory called
"fixtures" and renamed to "gabbits.py". "gabbi.py" can't be used
because of naming conflicts while importing.

This is a small part of ongoing work related to
blueprint placement-extract

Change-Id: I126ada549d3879f89d1ec64b743da14807a39351

nova/tests/fixtures.py

@@ -37,7 +37,6 @@ from requests import adapters
 from wsgi_intercept import interceptor
 
 from nova.api.openstack.compute import tenant_networks
-from nova.api.openstack.placement import deploy as placement_deploy
 from nova.api.openstack import wsgi_app
 from nova.api import wsgi
 from nova.compute import rpcapi as compute_rpcapi
@@ -53,6 +52,7 @@ from nova import quota as nova_quota
 from nova import rpc
 from nova import service
 from nova.tests.functional.api import client
+from nova.tests.functional.api.openstack.placement.fixtures import placement
 from nova.tests import uuidsentinel
 
 _TRUE_VALUES = ('True', 'true', '1', 'yes')
@@ -1691,7 +1691,7 @@ class PlacementApiClient(object):
             self.fixture._fake_put(None, url, body, **kwargs))
 
 
-class PlacementFixture(fixtures.Fixture):
+class PlacementFixture(placement.PlacementFixture):
     """A fixture to placement operations.
 
     Runs a local WSGI server bound on a free port and having the Placement
@@ -1703,21 +1703,9 @@ class PlacementFixture(fixtures.Fixture):
     all calls would be passing this token.
     """
 
-    def __init__(self, token='admin'):
-        self.token = token
-
     def setUp(self):
         super(PlacementFixture, self).setUp()
 
-        self.useFixture(ConfPatcher(group='api', auth_strategy='noauth2'))
-        loader = placement_deploy.loadapp(CONF)
-        app = lambda: loader
-        host = uuidsentinel.placement_host
-        self.endpoint = 'http://%s/placement' % host
-        intercept = interceptor.RequestsInterceptor(app, url=self.endpoint)
-        intercept.install_intercept()
-        self.addCleanup(intercept.uninstall_intercept)
-
         # Turn off manipulation of socket_options in TCPKeepAliveAdapter
         # to keep wsgi-intercept happy. Replace it with the method
         # from its superclass.

nova/tests/functional/api/openstack/placement/fixtures/placement.py

@@ -0,0 +1,76 @@
+#    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
+from oslo_config import cfg
+from oslo_utils import uuidutils
+from wsgi_intercept import interceptor
+
+from nova.api.openstack.placement import deploy
+
+
+CONF = cfg.CONF
+
+
+class ConfPatcher(fixtures.Fixture):
+    """Fixture to patch and restore global CONF.
+
+    This also resets overrides for everything that is patched during
+    its teardown.
+    """
+    # TODO(cdent): This is intentionally duplicated from nova's fixtures.
+    # This comment becomes redundant once placement is extracted.
+
+    def __init__(self, **kwargs):
+        """Constructor
+
+        :params group: if specified all config options apply to that group.
+
+        :params **kwargs: the rest of the kwargs are processed as a
+        set of key/value pairs to be set as configuration override.
+
+        """
+        super(ConfPatcher, self).__init__()
+        self.group = kwargs.pop('group', None)
+        self.args = kwargs
+
+    def setUp(self):
+        super(ConfPatcher, self).setUp()
+        for k, v in self.args.items():
+            self.addCleanup(CONF.clear_override, k, self.group)
+            CONF.set_override(k, v, self.group)
+
+
+class PlacementFixture(fixtures.Fixture):
+    """A fixture to placement operations.
+
+    Runs a local WSGI server bound on a free port and having the Placement
+    application with NoAuth middleware.
+    This fixture also prevents calling the ServiceCatalog for getting the
+    endpoint.
+
+    It's possible to ask for a specific token when running the fixtures so
+    all calls would be passing this token.
+    """
+    def __init__(self, token='admin'):
+        self.token = token
+
+    def setUp(self):
+        super(PlacementFixture, self).setUp()
+
+        self.useFixture(ConfPatcher(group='api', auth_strategy='noauth2'))
+        loader = deploy.loadapp(CONF)
+        app = lambda: loader
+        self.endpoint = 'http://%s/placement' % uuidutils.generate_uuid()
+        intercept = interceptor.RequestsInterceptor(app, url=self.endpoint)
+        intercept.install_intercept()
+        self.addCleanup(intercept.uninstall_intercept)

nova/tests/functional/api/openstack/placement/test_placement_api.py

@@ -17,7 +17,9 @@ import wsgi_intercept
 from gabbi import driver
 
 from nova.tests import fixtures as nova_fixtures
-from nova.tests.functional.api.openstack.placement import fixtures
+# TODO(cdent): This whitespace blight will go away post extraction.
+from nova.tests.functional.api.openstack.placement.fixtures \
+        import gabbits as fixtures
 
 # Check that wsgi application response headers are always
 # native str.