Add fullstack tests for update network's segmentation_id

Update of network's segmentation_id was introduced in [1] but
there was no API tests for it.
This patch adds fullstack tests which tests API calls to update
this attribute of vlan networks.

It is done in fullstack tests instead of tempest API test becasuse
this feature is dependend of used backend driver. Currently it is
supported only by openvswitch L2 agent.
In tempest API tests we don't have full controll of what L2 agent
is used to bound ports thus we can't be sure how test will behave.

In fullstack tests we have full control of this so it's easier to
implement such tests.

[1] https://bugs.launchpad.net/neutron/+bug/1806052

Change-Id: I5292c67bda2aff08d5302517b5bdf9d8472af8c4

neutron/tests/fullstack/test_segmentation_id.py

@@ -0,0 +1,101 @@
+#    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.
+
+from neutron_lib import constants
+from neutronclient.common import exceptions
+from oslo_utils import uuidutils
+
+from neutron.tests.fullstack import base
+from neutron.tests.fullstack.resources import config
+from neutron.tests.fullstack.resources import environment
+from neutron.tests.unit import testlib_api
+
+load_tests = testlib_api.module_load_tests
+
+
+class TestSegmentationId(base.BaseFullStackTestCase):
+
+    scenarios = [
+        ('Open vSwitch Agent', {'l2_agent_type': constants.AGENT_TYPE_OVS}),
+        ('Linux Bridge Agent', {
+            'l2_agent_type': constants.AGENT_TYPE_LINUXBRIDGE})]
+
+    def setUp(self):
+        hosts_description = [
+            environment.HostDescription(
+                l2_agent_type=self.l2_agent_type, l3_agent=False)]
+        env = environment.Environment(
+            environment.EnvironmentDescription(),
+            hosts_description)
+
+        super(TestSegmentationId, self).setUp(env)
+        self.tenant_id = uuidutils.generate_uuid()
+
+    def _create_network(self):
+        seg_id = 100
+        network = self.safe_client.create_network(
+            self.tenant_id, network_type="vlan", segmentation_id=seg_id,
+            physical_network=config.PHYSICAL_NETWORK_NAME)
+        self.assertEqual(seg_id, network['provider:segmentation_id'])
+
+        # Ensure that segmentation_id is really set properly in DB
+        network = self.safe_client.client.show_network(
+            network['id'])['network']
+        self.assertEqual(seg_id, network['provider:segmentation_id'])
+        return network
+
+    def _update_segmentation_id(self, network):
+        # Now change segmentation_id to some other value
+        new_seg_id = network['provider:segmentation_id'] + 1
+        new_net_args = {'provider:segmentation_id': new_seg_id}
+        network = self.safe_client.update_network(
+            network['id'], **new_net_args)
+        self.assertEqual(
+            new_seg_id, network['provider:segmentation_id'])
+        # Ensure that segmentation_id was really changed
+        network = self.safe_client.client.show_network(
+            network['id'])['network']
+        self.assertEqual(new_seg_id, network['provider:segmentation_id'])
+
+    def test_change_segmentation_id_no_ports_in_network(self):
+        network = self._create_network()
+        self._update_segmentation_id(network)
+
+    def test_change_segmentation_id_with_unbound_ports_in_network(self):
+        network = self._create_network()
+
+        self.safe_client.create_subnet(
+            self.tenant_id, network['id'], '20.0.0.0/24')
+
+        # Unbound port
+        self.safe_client.create_port(self.tenant_id, network['id'])
+        # Port failed to bind
+        self.safe_client.create_port(self.tenant_id, network['id'],
+                                     "non-exisiting-host")
+
+        self._update_segmentation_id(network)
+
+    def test_change_segmentation_id_with_bound_ports_in_network(self):
+        network = self._create_network()
+
+        self.safe_client.create_subnet(
+            self.tenant_id, network['id'], '20.0.0.0/24')
+        self.safe_client.create_port(self.tenant_id, network['id'],
+                                     self.environment.hosts[0].hostname)
+
+        if self.l2_agent_type == constants.AGENT_TYPE_LINUXBRIDGE:
+            # Linuxbridge agent don't support update of segmentation_id for
+            # the network so this should raise an exception
+            self.assertRaises(exceptions.BadRequest,
+                              self._update_segmentation_id, network)
+        else:
+            self._update_segmentation_id(network)