Move cleanup of launched instances to common class

Use the nomenclature for resource cleanup as defined in the
`BaseCharmTest`.

zaza/openstack/charm_tests/neutron/tests.py

@@ -616,24 +616,6 @@ class NeutronNetworkingBase(test_utils.OpenStackBaseTest):
         super(NeutronNetworkingBase, cls).setUpClass()
         cls.neutron_client = (
             openstack_utils.get_neutron_session_client(cls.keystone_session))
-        # NOTE(fnordahl): in the event of a test failure we do not want to run
-        # tear down code as it will make debugging a problem virtually
-        # impossible.  To alleviate each test method will set the
-        # `run_tearDown` instance variable at the end which will let us run
-        # tear down only when there were no failure.
-        cls.run_tearDown = False
-
-    @classmethod
-    def tearDown(cls):
-        """Remove test resources."""
-        if cls.run_tearDown:
-            logging.info('Running teardown')
-            for server in cls.nova_client.servers.list():
-                if server.name.startswith(cls.RESOURCE_PREFIX):
-                    openstack_utils.delete_resource(
-                        cls.nova_client.servers,
-                        server.id,
-                        msg="server")
 
     @tenacity.retry(wait=tenacity.wait_exponential(multiplier=1, max=60),
                     reraise=True, stop=tenacity.stop_after_attempt(8))
@@ -803,7 +785,7 @@ class NeutronNetworkingTest(NeutronNetworkingBase):
         self.launch_guests()
         instance_1, instance_2 = self.retrieve_guests()
         self.check_connectivity(instance_1, instance_2)
-        self.run_tearDown = True
+        self.run_resource_cleanup = True
 
 
 class NeutronNetworkingVRRPTests(NeutronNetworkingBase):

zaza/openstack/charm_tests/test_utils.py

@@ -440,6 +440,20 @@ class OpenStackBaseTest(BaseCharmTest):
         cls.nova_client = (
             openstack_utils.get_nova_session_client(cls.keystone_session))
 
+    def resource_cleanup(self):
+        """Remove test resources."""
+        try:
+            logging.info('Removing instances launched by test ({}*)'
+                         .format(self.RESOURCE_PREFIX))
+            for server in self.nova_client.servers.list():
+                if server.name.startswith(self.RESOURCE_PREFIX):
+                    openstack_utils.delete_resource(
+                        self.nova_client.servers,
+                        server.id,
+                        msg="server")
+        except AttributeError:
+            # Test did not define self.RESOURCE_PREFIX, ignore.
+            pass
 
     def launch_guest(self, guest_name, userdata=None):
         """Launch two guests to use in tests.