ML2 plugin cannot raise NoResultFound exception

The ML2 plugin cannot raise NoResultFound exception because it does not
use the correct sqlalchemy library:
'from sqlalchemy import exc as ...' instead of 'from sqlalchemy.orm
import exc as ...'

Closes-Bug: #1277914
Change-Id: If3819adc62b9254f0c08eea6dcfcf5f06288e20e

neutron/plugins/ml2/plugin.py

@@ -15,6 +15,7 @@
 
 from oslo.config import cfg
 from sqlalchemy import exc as sql_exc
+from sqlalchemy.orm import exc as sa_exc
 
 from neutron.agent import securitygroups_rpc as sg_rpc
 from neutron.api.rpc.agentnotifiers import dhcp_rpc_agent_api
@@ -595,7 +596,7 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                 port_db = (session.query(models_v2.Port).
                            enable_eagerloads(False).
                            filter_by(id=id).with_lockmode('update').one())
-            except sql_exc.NoResultFound:
+            except sa_exc.NoResultFound:
                 raise exc.PortNotFound(port_id=id)
             original_port = self._make_port_dict(port_db)
             updated_port = super(Ml2Plugin, self).update_port(context, id,
@@ -653,7 +654,7 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                 port_db = (session.query(models_v2.Port).
                            enable_eagerloads(False).
                            filter_by(id=id).with_lockmode('update').one())
-            except sql_exc.NoResultFound:
+            except sa_exc.NoResultFound:
                 # the port existed when l3plugin.prevent_l3_port_deletion
                 # was called but now is already gone
                 LOG.debug(_("The port '%s' was deleted"), id)

neutron/tests/unit/ml2/test_ml2_plugin.py

@@ -13,10 +13,16 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import mock
+
+from neutron.common import exceptions as exc
+from neutron import context
 from neutron.extensions import multiprovidernet as mpnet
 from neutron.extensions import portbindings
 from neutron.extensions import providernet as pnet
+from neutron import manager
 from neutron.plugins.ml2 import config
+from neutron.plugins.ml2 import plugin as ml2_plugin
 from neutron.tests.unit import _test_extension_portbindings as test_bindings
 from neutron.tests.unit import test_db_plugin as test_plugin
 from neutron.tests.unit import test_extension_extradhcpopts as test_dhcpopts
@@ -90,6 +96,23 @@ class TestMl2PortsV2(test_plugin.TestPortsV2, Ml2PluginV2TestCase):
             self.assertEqual(port['port']['status'], 'DOWN')
             self.assertEqual(self.port_create_status, 'DOWN')
 
+    def test_update_non_existent_port(self):
+        ctx = context.get_admin_context()
+        plugin = manager.NeutronManager.get_plugin()
+        data = {'port': {'admin_state_up': False}}
+        self.assertRaises(exc.PortNotFound, plugin.update_port, ctx,
+                          'invalid-uuid', data)
+
+    def test_delete_non_existent_port(self):
+        ctx = context.get_admin_context()
+        plugin = manager.NeutronManager.get_plugin()
+        with mock.patch.object(ml2_plugin.LOG, 'debug') as log_debug:
+            plugin.delete_port(ctx, 'invalid-uuid', l3_port_check=False)
+            log_debug.assert_has_calls([
+                mock.call(_("Deleting port %s"), 'invalid-uuid'),
+                mock.call(_("The port '%s' was deleted"), 'invalid-uuid')
+            ])
+
 
 class TestMl2PortBinding(Ml2PluginV2TestCase,
                          test_bindings.PortBindingsTestCase):