Improve mocking in HeatTestCase

As the mock lib is going to be used more actively, there is a need
to improve our boilerplate code in respect to mock.

Changes in this patch include:
* `patchobject` now accepts kwargs and passes them to `mock.patch.object`;
* added `patch` method that uses mock.patch (similar to `patchobject`)
  - NOTE: this shadows `testtools.TestCase.patch` method that uses
    simple monkey-patching in favor of mock-based patching,
    relevant comment added in the code;
* test code changed accordingly where needed.

Change-Id: I779cab63249d5eb1962e9ec388cd31f3df4a4189

contrib/rackspace/rackspace/tests/test_auto_scale.py

@@ -204,8 +204,8 @@ class ScalingGroupTest(HeatTestCase):
         for res_name, res_class in auto_scale.resource_mapping().items():
             resource._register_class(res_name, res_class)
         self.fake_auto_scale = FakeAutoScale()
-        self.patch(clients.OpenStackClients,
+        self.patchobject(clients.OpenStackClients, 'auto_scale',
-                   'auto_scale', lambda resource: self.fake_auto_scale)
+                         return_value=self.fake_auto_scale, create=True)
 
     def _setup_test_stack(self):
         self.stack = utils.parse_stack(self.group_template)
@@ -382,7 +382,7 @@ Resources:
             if count < 3:
                 raise auto_scale.Forbidden("Not empty!")
 
-        self.patch(self.fake_auto_scale, 'delete', delete)
+        self.patchobject(self.fake_auto_scale, 'delete', new=delete)
         resource = self.stack['my_group']
         scheduler.TaskRunner(resource.delete)()
         # It really called delete until it succeeded:
@@ -398,7 +398,7 @@ Resources:
         def delete(group_id):
             1 / 0
 
-        self.patch(self.fake_auto_scale, 'delete', delete)
+        self.patchobject(self.fake_auto_scale, 'delete', new=delete)
         resource = self.stack['my_group']
         err = self.assertRaises(
             exception.ResourceFailure, scheduler.TaskRunner(resource.delete))
@@ -426,8 +426,8 @@ class PolicyTest(HeatTestCase):
         for res_name, res_class in auto_scale.resource_mapping().items():
             resource._register_class(res_name, res_class)
         self.fake_auto_scale = FakeAutoScale()
-        self.patch(clients.OpenStackClients,
+        self.patchobject(clients.OpenStackClients, 'auto_scale',
-                   'auto_scale', lambda resource: self.fake_auto_scale)
+                         return_value=self.fake_auto_scale, create=True)
 
     def _setup_test_stack(self, template):
         self.stack = utils.parse_stack(template)
@@ -570,8 +570,8 @@ class WebHookTest(HeatTestCase):
         for res_name, res_class in auto_scale.resource_mapping().items():
             resource._register_class(res_name, res_class)
         self.fake_auto_scale = FakeAutoScale()
-        self.patch(clients.OpenStackClients,
+        self.patchobject(clients.OpenStackClients, 'auto_scale',
-                   'auto_scale', lambda resource: self.fake_auto_scale)
+                         return_value=self.fake_auto_scale, create=True)
 
     def _setup_test_stack(self, template):
         self.stack = utils.parse_stack(template)

heat/tests/common.py

@@ -110,8 +110,15 @@ class HeatTestCase(testscenarios.WithScenarios,
         self.m.StubOutWithMock(scheduler, 'wallclock')
         scheduler.wallclock = fake_wallclock
 
-    def patchobject(self, obj, attr):
+    def patchobject(self, obj, attr, **kwargs):
-        mockfixture = self.useFixture(mockpatch.PatchObject(obj, attr))
+        mockfixture = self.useFixture(mockpatch.PatchObject(obj, attr,
+                                                            **kwargs))
+        return mockfixture.mock
+
+    # NOTE(pshchelo): this overrides the testtools.TestCase.patch method
+    # that does simple monkey-patching in favor of mock's patching
+    def patch(self, target, **kwargs):
+        mockfixture = self.useFixture(mockpatch.Patch(target, **kwargs))
         return mockfixture.mock
 
     def stub_keystoneclient(self, fake_client=None, **kwargs):

heat/tests/test_engine_service.py

@@ -24,7 +24,6 @@ from oslo.config import cfg
 from oslo import messaging
 from oslo.messaging.rpc import client as rpc_client
 from oslo.messaging.rpc import dispatcher
-from oslotest import mockpatch
 import six
 
 from heat.common import exception
@@ -175,12 +174,6 @@ resources:
 '''
 
 
-def mock_warnings(test):
-        mock_warnings = mock.patch('heat.engine.service.warnings')
-        mock_warnings.start()
-        test.addCleanup(mock_warnings.stop)
-
-
 def get_wordpress_stack(stack_name, ctx):
     t = template_format.parse(wp_template)
     template = parser.Template(t)
@@ -432,7 +425,7 @@ class StackServiceCreateUpdateDeleteTest(HeatTestCase):
     def setUp(self):
         super(StackServiceCreateUpdateDeleteTest, self).setUp()
         self.ctx = utils.dummy_context()
-        mock_warnings(self)
+        self.patch('heat.engine.service.warnings')
         self.man = service.EngineService('a-host', 'a-topic')
         self.man.create_periodic_tasks()
 
@@ -1257,7 +1250,7 @@ class StackServiceUpdateSuspendedNotSupportedTest(HeatTestCase):
     def setUp(self):
         super(StackServiceUpdateSuspendedNotSupportedTest, self).setUp()
         self.ctx = utils.dummy_context()
-        mock_warnings(self)
+        self.patch('heat.engine.service.warnings')
         self.man = service.EngineService('a-host', 'a-topic')
 
     def test_stack_update_suspended(self):
@@ -1291,7 +1284,7 @@ class StackServiceSuspendResumeTest(HeatTestCase):
     def setUp(self):
         super(StackServiceSuspendResumeTest, self).setUp()
         self.ctx = utils.dummy_context()
-        mock_warnings(self)
+        self.patch('heat.engine.service.warnings')
         self.man = service.EngineService('a-host', 'a-topic')
         self.man.create_periodic_tasks()
 
@@ -1365,7 +1358,7 @@ class StackServiceAuthorizeTest(HeatTestCase):
         super(StackServiceAuthorizeTest, self).setUp()
 
         self.ctx = utils.dummy_context(tenant_id='stack_service_test_tenant')
-        mock_warnings(self)
+        self.patch('heat.engine.service.warnings')
         self.eng = service.EngineService('a-host', 'a-topic')
         self.eng.engine_id = 'engine-fake-uuid'
         cfg.CONF.set_default('heat_stack_user_role', 'stack_user_role')
@@ -1460,7 +1453,7 @@ class StackServiceTest(HeatTestCase):
         super(StackServiceTest, self).setUp()
 
         self.ctx = utils.dummy_context(tenant_id='stack_service_test_tenant')
-        mock_warnings(self)
+        self.patch('heat.engine.service.warnings')
         self.eng = service.EngineService('a-host', 'a-topic')
         self.eng.create_periodic_tasks()
         self.eng.engine_id = 'engine-fake-uuid'
@@ -2722,7 +2715,7 @@ class SoftwareConfigServiceTest(HeatTestCase):
     def setUp(self):
         super(SoftwareConfigServiceTest, self).setUp()
         self.ctx = utils.dummy_context()
-        mock_warnings(self)
+        self.patch('heat.engine.service.warnings')
         self.engine = service.EngineService('a-host', 'a-topic')
 
     def _create_software_config(
@@ -3052,15 +3045,12 @@ class ThreadGroupManagerTest(HeatTestCase):
         self.engine_id = 'engine_id'
         self.stack = mock.Mock()
         self.lock_mock = mock.Mock()
-        self.stlock_mock = self.useFixture(
+        self.stlock_mock = self.patch('heat.engine.service.stack_lock')
-            mockpatch.Patch('heat.engine.service.stack_lock')).mock
         self.stlock_mock.StackLock.return_value = self.lock_mock
         self.tg_mock = mock.Mock()
-        self.thg_mock = self.useFixture(
+        self.thg_mock = self.patch('heat.engine.service.threadgroup')
-            mockpatch.Patch('heat.engine.service.threadgroup')).mock
         self.thg_mock.ThreadGroup.return_value = self.tg_mock
-        self.cfg_mock = self.useFixture(
+        self.cfg_mock = self.patch('heat.engine.service.cfg')
-            mockpatch.Patch('heat.engine.service.cfg')).mock
 
     def test_tgm_start_with_lock(self):
         thm = service.ThreadGroupManager()

heat/tests/test_heat_autoscaling_group.py

@@ -13,7 +13,6 @@
 import copy
 import datetime
 import itertools
-import mock
 
 from oslo.config import cfg
 
@@ -436,11 +435,9 @@ class RollingUpdatesTest(HeatTestCase):
             templates = [definitions[name] for name in created_order]
             batches.append(templates)
 
-        patcher = mock.patch.object(
+        self.patchobject(
             stack_resource.StackResource, 'update_with_template',
             side_effect=update_with_template, wraps=rsrc.update_with_template)
-        patcher.start()
-        self.addCleanup(patcher.stop)
 
         props = copy.deepcopy(rsrc.properties.data)
         props['resource']['properties']['Foo'] = 'Hi'

heat/tests/test_metadata_refresh.py

@@ -12,7 +12,6 @@
 #    under the License.
 
 
-import mock
 import mox
 from oslo.config import cfg
 
@@ -218,9 +217,7 @@ class WaitCondMetadataUpdateTest(HeatTestCase):
     def setUp(self):
         super(WaitCondMetadataUpdateTest, self).setUp()
         self.stub_keystoneclient()
-        self.mock_warnings = mock.patch('heat.engine.service.warnings')
+        self.patch('heat.engine.service.warnings')
-        self.mock_warnings.start()
-        self.addCleanup(self.mock_warnings.stop)
 
         self.man = service.EngineService('a-host', 'a-topic')
         cfg.CONF.set_default('heat_waitcondition_server_url',

heat/tests/test_resource.py

@@ -54,9 +54,7 @@ class ResourceTest(HeatTestCase):
         self.stack = parser.Stack(utils.dummy_context(), 'test_stack',
                                   parser.Template(empty_template), env=env,
                                   stack_id=str(uuid.uuid4()))
-        self.mock_warnings = mock.patch('heat.engine.resource.warnings')
+        self.patch('heat.engine.resource.warnings')
-        self.mock_warnings.start()
-        self.addCleanup(self.mock_warnings.stop)
 
     def test_get_class_ok(self):
         cls = resource.get_class('GenericResourceType')
@@ -926,9 +924,7 @@ class ResourceAdoptTest(HeatTestCase):
         super(ResourceAdoptTest, self).setUp()
         resource._register_class('GenericResourceType',
                                  generic_rsrc.GenericResource)
-        self.mock_warnings = mock.patch('heat.engine.resource.warnings')
+        self.patch('heat.engine.resource.warnings')
-        self.mock_warnings.start()
-        self.addCleanup(self.mock_warnings.stop)
 
     def test_adopt_resource_success(self):
         adopt_data = '{}'
@@ -1504,9 +1500,7 @@ class MetadataTest(HeatTestCase):
 
         scheduler.TaskRunner(self.res.create)()
         self.addCleanup(self.stack.delete)
-        self.mock_warnings = mock.patch('heat.engine.resource.warnings')
+        self.patch('heat.engine.resource.warnings')
-        self.mock_warnings.start()
-        self.addCleanup(self.mock_warnings.stop)
 
     def test_read_initial(self):
         self.assertEqual({'Test': 'Initial metadata'}, self.res.metadata_get())

heat/tests/test_validate.py

@@ -12,7 +12,6 @@
 #    under the License.
 
 from glanceclient import exc as glance_exceptions
-import mock
 import six
 
 from heat.common import exception
@@ -812,9 +811,7 @@ class validateTest(HeatTestCase):
         self.gc = fakes.FakeClient()
         resources.initialise()
         self.ctx = utils.dummy_context()
-        self.mock_warnings = mock.patch('heat.engine.service.warnings')
+        self.patch('heat.engine.service.warnings')
-        self.mock_warnings.start()
-        self.addCleanup(self.mock_warnings.stop)
 
     def _mock_get_image_id_success(self, imageId_input, imageId):
         self.m.StubOutWithMock(glance.GlanceClientPlugin, 'get_image_id')