Removes unnecessary Embrane module-level mocks

The embrane unit tests install a magicmock into
the system modules at the module level which
persists across all unit tests and isn't required.
This patch removes the unnecessary and limits the
life of the module mocks where they are necessary.

Partial-Bug: #1316401
Change-Id: Iaa38ee0c6821d46a6d78eefef39006df2c1c47e5

neutron/tests/unit/embrane/test_embrane_defaults.py

@@ -17,17 +17,11 @@
 #
 # @author:  Ivar Lazzaro, Embrane, Inc.
 
-import sys
-
-import mock
 from oslo.config import cfg
 
 from neutron.plugins.embrane.common import config  # noqa
 from neutron.tests import base
 
-# Need to mock heleosapi.
-sys.modules["heleosapi"] = mock.Mock()
-
 
 class ConfigurationTest(base.BaseTestCase):
 

neutron/tests/unit/embrane/test_embrane_l3_plugin.py

@@ -17,9 +17,6 @@
 #
 # @author:  Ivar Lazzaro, Embrane, Inc.
 
-import sys
-
-import mock
 from oslo.config import cfg
 
 from neutron.db import api as db
@@ -29,7 +26,6 @@ from neutron.tests.unit import test_l3_plugin as router_test
 
 PLUGIN_NAME = ('neutron.plugins.embrane.plugins.embrane_fake_plugin.'
                'EmbraneFakePlugin')
-sys.modules["heleosapi"] = mock.Mock()
 
 
 class TestEmbraneL3NatDBTestCase(router_test.L3NatDBIntTestCase):

neutron/tests/unit/embrane/test_embrane_neutron_plugin.py

@@ -16,7 +16,6 @@
 #    under the License.
 #
 # @author:  Ivar Lazzaro, Embrane, Inc.
-
 import sys
 
 import mock
@@ -28,7 +27,6 @@ from neutron.tests.unit import test_db_plugin as test_plugin
 
 PLUGIN_NAME = ('neutron.plugins.embrane.plugins.embrane_fake_plugin.'
                'EmbraneFakePlugin')
-sys.modules["heleosapi"] = mock.Mock()
 
 
 class EmbranePluginV2TestCase(test_plugin.NeutronDbPluginV2TestCase):
@@ -36,7 +34,11 @@ class EmbranePluginV2TestCase(test_plugin.NeutronDbPluginV2TestCase):
 
     def setUp(self):
         cfg.CONF.set_override('admin_password', "admin123", 'heleos')
+        p = mock.patch.dict(sys.modules, {'heleosapi': mock.Mock()})
+        p.start()
         self.addCleanup(db.clear_db)
+        # dict patches must be explicitly stopped
+        self.addCleanup(p.stop)
         super(EmbranePluginV2TestCase, self).setUp(self._plugin_name)
 
 

neutron/tests/unit/services/loadbalancer/drivers/embrane/test_embrane_defaults.py

@@ -17,16 +17,11 @@
 #
 # @author:  Ivar Lazzaro, Embrane, Inc.
 
-import sys
-
-import mock
 from oslo.config import cfg
 
 from neutron.services.loadbalancer.drivers.embrane import config  # noqa
 from neutron.tests import base
 
-sys.modules["heleosapi"] = mock.Mock()
-
 
 class ConfigurationTest(base.BaseTestCase):
 

neutron/tests/unit/services/loadbalancer/drivers/embrane/test_plugin_driver.py

@@ -20,16 +20,19 @@
 import sys
 
 import mock
-sys.modules["heleosapi"] = mock.Mock()
 from oslo.config import cfg
 
 from neutron import context
 from neutron.openstack.common.db import exception as n_exc
+from neutron.tests.unit.db.loadbalancer import test_db_loadbalancer
+
+HELEOSAPIMOCK = mock.Mock()
+sys.modules["heleosapi"] = HELEOSAPIMOCK
 from neutron.services.loadbalancer.drivers.embrane import config  # noqa
 from neutron.services.loadbalancer.drivers.embrane import constants as h_con
 from neutron.services.loadbalancer.drivers.embrane import db as h_db
-from neutron.tests.unit.db.loadbalancer import test_db_loadbalancer
-
+# Stop the mock from persisting indefinitely in the global modules space
+del sys.modules["heleosapi"]
 
 EMBRANE_PROVIDER = ('LOADBALANCER:lbaas:neutron.services.'
                     'loadbalancer.drivers.embrane.driver.'
@@ -42,10 +45,12 @@ class TestLoadBalancerPluginBase(
     def setUp(self):
         cfg.CONF.set_override('admin_password', "admin123", 'heleoslb')
         cfg.CONF.set_override('sync_interval', 0, 'heleoslb')
-
+        mock.patch.dict(sys.modules, {'heleosapi': HELEOSAPIMOCK}).start()
         super(TestLoadBalancerPluginBase, self).setUp(
             lbaas_provider=EMBRANE_PROVIDER)
         self.driver = self.plugin.drivers['lbaas']
+        # prevent module mock from saving calls between tests
+        self.addCleanup(HELEOSAPIMOCK.reset_mock)
 
 
 class TestLoadBalancerPlugin(test_db_loadbalancer.TestLoadBalancer,