Fix looking for ovs agent based on compute node name

In neutron agents faults tests module, there is test which looks
for neutron-ovs-agent which runs on same host as VM is spawned to
stop this neutron-ovs-agent.
This usually worked fine, but in case e.g. of TripleO hostname
given in neutron agents list contained full domain name and
hostname from nova's output containes short name.
Because of this missmatch there was no neutron-ovs-agent found to
stop and test was failing.
This patch fixes this issue by changing comparison of hostnames
of vm's host and agent's host.

Additionally this patch adds proper handling of the case when
neutron-ovs-agent isn't found.

Change-Id: If240188392feb6067af4f9a4a82e8ed95b4b99ee

tobiko/__init__.py

@@ -25,6 +25,7 @@ from tobiko.common import _operation
 from tobiko.common import _os
 from tobiko.common import _select
 from tobiko.common import _skip
+from tobiko.common import _utils
 
 
 details_content = _detail.details_content
@@ -89,6 +90,8 @@ skip = _skip.skip
 skip_if = _skip.skip_if
 skip_unless = _skip.skip_unless
 
+get_short_hostname = _utils.get_short_hostname
+
 
 from tobiko import config  # noqa
 config.init_config()

tobiko/common/_utils.py

@@ -0,0 +1,18 @@
+# Copyright 2020 Red Hat
+#
+#    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 __future__ import absolute_import
+
+
+def get_short_hostname(hostname):
+    return hostname.lower().split('.', 1)[0]

tobiko/tests/faults/agents/test_neutron_agents.py

@@ -31,6 +31,10 @@ from tobiko.shell import sh
 LOG = log.getLogger(__name__)
 
 
+class AgentNotFoundOnHost(tobiko.TobikoException):
+    message = ("Agent {agent_type!s} not found on the host {host!s}")
+
+
 class AgentTestMixin(object):
 
     def stop_service_on_agents(self, service_name, agents):
@@ -341,9 +345,12 @@ class OvsAgentTest(testtools.TestCase, AgentTestMixin):
             self.agent_service_name, self.stopped_agents)
 
     def _get_agent_from_host(self, host):
+        host_shortname = tobiko.get_short_hostname(host.name)
         for agent in self.ovs_agents:
-            if agent['host'] == host.name:
+            if host_shortname == tobiko.get_short_hostname(agent['host']):
                 return agent
+        raise AgentNotFoundOnHost(agent_type="neutron-ovs-agent",
+                                  host=host.name)
 
     def test_vm_reachability_during_stop_ovs_agent(self):
         # Check if vm is reachable before test

tobiko/tests/unit/test_utils.py

@@ -0,0 +1,30 @@
+# Copyright 2020 Red Hat
+#
+#    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 __future__ import absolute_import
+
+import tobiko
+from tobiko.tests import unit
+
+
+class UtilsTests(unit.TobikoUnitTest):
+
+    def test_get_short_hostname(self):
+        self.assertEqual("testhost", tobiko.get_short_hostname("testhost"))
+        self.assertEqual("testhost", tobiko.get_short_hostname("TesTHoSt"))
+        self.assertEqual(
+            "testhost", tobiko.get_short_hostname("testhost.domain"))
+        self.assertEqual(
+            "testhost", tobiko.get_short_hostname("teSthOsT.dOmAin"))
+        self.assertEqual("testhost", tobiko.get_short_hostname("testhost."))
+        self.assertEqual("testhost", tobiko.get_short_hostname("TesTHoSt."))