NetcatTester.stop_processes skip "No such process" exception

If any of the processes, client or server, spawned by NetcatTester is
not present during the stop command (kill signal sent), by default the
method will not raise an exception.

Change-Id: If8cf47a01dc353734ad07ca6cd4db7bec6c90fb6
Closes-Bug: #1852869

neutron/tests/common/net_helpers.py

@@ -28,6 +28,7 @@ import time
 import fixtures
 import netaddr
 from neutron_lib import constants as n_const
+from neutron_lib import exceptions as n_exc
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import uuidutils
@@ -554,13 +555,22 @@ class NetcatTester(object):
         proc = RootHelperProcess(cmd, namespace=namespace)
         return proc
 
-    def stop_processes(self):
+    def stop_processes(self, skip_errors=None):
+        skip_errors = (['No such process'] if skip_errors is None
+                       else skip_errors)
         for proc_attr in ('_client_process', '_server_process'):
             proc = getattr(self, proc_attr)
             if proc:
-                if proc.poll() is None:
-                    proc.kill()
-                    proc.wait()
+                try:
+                    if proc.poll() is None:
+                        proc.kill()
+                        proc.wait()
+                except n_exc.ProcessExecutionError as exc:
+                    for skip_error in skip_errors:
+                        if skip_error in str(exc):
+                            break
+                    else:
+                        raise exc
                 setattr(self, proc_attr, None)
 
 

neutron/tests/functional/tests/common/test_net_helpers.py

@@ -0,0 +1,75 @@
+# Copyright 2019 Red Hat, Inc.
+#
+#    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.
+
+import signal
+
+import mock
+
+from neutron_lib import exceptions as n_exc
+
+from neutron.agent.linux import ip_lib
+from neutron.agent.linux import utils
+from neutron.common import utils as n_utils
+from neutron.tests.common import net_helpers
+from neutron.tests.functional import base
+
+
+class NetcatTesterTestCase(base.BaseSudoTestCase):
+
+    def setUp(self):
+        super(NetcatTesterTestCase, self).setUp()
+        self.ns1 = self.useFixture(net_helpers.NamespaceFixture('nc-')).name
+        self.ns2 = self.useFixture(net_helpers.NamespaceFixture('nc-')).name
+        self.nc = net_helpers.NetcatTester(self.ns1, self.ns2, '10.30.0.2',
+                                           '1234', 'tcp')
+        ip_wrapper = ip_lib.IPWrapper(namespace=self.ns1)
+        veth1, veth2 = ip_wrapper.add_veth('veth1', 'veth2', self.ns2)
+        veth1.link.set_up()
+        veth1.addr.add('10.30.0.1/24')
+        veth2.link.set_up()
+        veth2.addr.add('10.30.0.2/24')
+
+    def test_stop_process(self):
+        self.nc.test_connectivity()
+        server_pid = self.nc.server_process.child_pid
+        client_pid = self.nc.client_process.child_pid
+        self.assertTrue(utils.process_is_running(server_pid))
+        self.assertTrue(utils.process_is_running(client_pid))
+
+        self.nc.stop_processes()
+        self.assertFalse(utils.process_is_running(server_pid))
+        self.assertFalse(utils.process_is_running(client_pid))
+
+    def test_stop_process_no_process(self):
+        self.nc.test_connectivity()
+        client_pid = self.nc.client_process.child_pid
+        utils.execute(['kill', '-%d' % signal.SIGKILL, client_pid],
+                      run_as_root=True)
+        n_utils.wait_until_true(
+            lambda: not utils.process_is_running(client_pid), timeout=5)
+        with mock.patch.object(net_helpers.RootHelperProcess, 'poll',
+                               return_value=None):
+            self.assertRaises(n_exc.ProcessExecutionError,
+                              self.nc.stop_processes,
+                              skip_errors=[])
+
+    def test_stop_process_no_process_skip_no_process_exception(self):
+        self.nc.test_connectivity()
+        server_pid = self.nc.server_process.child_pid
+        utils.execute(['kill', '-%d' % signal.SIGKILL, server_pid],
+                      run_as_root=True)
+
+        with mock.patch.object(net_helpers.RootHelperProcess, 'poll',
+                               side_effect=[None, True, None, True]):
+            self.nc.stop_processes()