Add AllServicesCurrent fixture

This adds a fixture that simulates a fully up-to-date system where
all services are current. This is the vast majority of what we test
for our unit tests, of course.

Change-Id: I209cd0d986304b2d913f2cf49b5ba54dcc872c18

nova/tests/fixtures.py

@@ -28,12 +28,14 @@ from oslo_db.sqlalchemy import enginefacade
 from oslo_messaging import conffixture as messaging_conffixture
 import six
 
+from nova.compute import rpcapi as compute_rpcapi
 from nova import context
 from nova.db import migration
 from nova.db.sqlalchemy import api as session
 from nova import exception
 from nova import objects
 from nova.objects import base as obj_base
+from nova.objects import service as service_obj
 from nova import rpc
 from nova import service
 from nova.tests.functional.api import client
@@ -651,3 +653,15 @@ class ForbidNewLegacyNotificationFixture(fixtures.Fixture):
         self.notifier.fatal = False
         self.notifier.allowed_legacy_notification_event_types.remove(
                 '_decorated_function')
+
+
+class AllServicesCurrent(fixtures.Fixture):
+    def setUp(self):
+        super(AllServicesCurrent, self).setUp()
+        self.useFixture(fixtures.MonkeyPatch(
+            'nova.objects.Service.get_minimum_version_multi',
+            self._fake_minimum))
+        compute_rpcapi.LAST_VERSION = None
+
+    def _fake_minimum(self, *args, **kwargs):
+        return service_obj.SERVICE_VERSION

nova/tests/unit/test_fixtures.py

@@ -24,9 +24,11 @@ from oslo_log import log as logging
 from oslo_utils import uuidutils
 import testtools
 
+from nova.compute import rpcapi as compute_rpcapi
 from nova.db.sqlalchemy import api as session
 from nova import exception
 from nova.objects import base as obj_base
+from nova.objects import service as service_obj
 from nova.tests import fixtures
 from nova.tests.unit import conf_fixture
 from nova import utils
@@ -432,3 +434,21 @@ class TestStableObjectJsonFixture(testtools.TestCase):
         with fixtures.StableObjectJsonFixture():
             self.assertEqual(['a', 'z'],
                              obj.obj_to_primitive()['nova_object.changes'])
+
+
+class TestAllServicesCurrentFixture(testtools.TestCase):
+    @mock.patch('nova.objects.Service._db_service_get_minimum_version')
+    def test_services_current(self, mock_db):
+        mock_db.return_value = {'nova-compute': 123}
+        self.assertEqual(123, service_obj.Service.get_minimum_version(
+            None, 'nova-compute'))
+        mock_db.assert_called_once_with(None, ['nova-compute'],
+                                        use_slave=False)
+        mock_db.reset_mock()
+        compute_rpcapi.LAST_VERSION = 123
+        self.useFixture(fixtures.AllServicesCurrent())
+        self.assertIsNone(compute_rpcapi.LAST_VERSION)
+        self.assertEqual(service_obj.SERVICE_VERSION,
+                         service_obj.Service.get_minimum_version(
+                             None, 'nova-compute'))
+        self.assertFalse(mock_db.called)