Introduce @serial test execution decorator

Tempest provides a LockFixture to avoid two potentially interfering
tests to run in parallel. However, this solution does not scale when
we want to separate a set of tests from many other test cases. For
example, host aggregate and availability zone testing needs compute
hosts without any nova servers to be able to test moving computes
between aggregates but a lot of other tests are creating nova
servers. To fully separate these aggregate tests from the rest of
the tempest test cases, this patch proposes a @serial class decorator
to mark a test class to be run totally independently of any other test
classes.

Under the hood, the @serial decorator is implemented with a tempest-wide
interprocess read-write lock. The serial test classes always take the
write lock, while the non-serial classes take the read lock. The lock
allows in many readers OR a single writer. So the serial tests are run
independently from the rest.

To minimize the time a serial test blocks other tempest tests run in
parallel, this patch also introduced a serial_tests test directory to
store the serial tests. The current test ordering in a fresh env
uses alphabetical order so the serial tests will run at the end of
the execution not randomly in the middle. The gate uses fresh VMs
for every run so we can rely on this optimization there. In local
envs where tests are re-run, the subsequent runs will be ordered at
runtime by stestr. Therfore, a longer runtime might be observed due to
locking, but the correctness of the test execution is still kept.

Related-Bug: #821732
Change-Id: I0181517edab75f586464a38c4811417f888783b1

1 files changed, 0 insertions, 142 deletions

diff --git a/tempest/scenario/test_aggregates_basic_ops.py b/tempest/scenario/test_aggregates_basic_ops.py
deleted file mode 100644
index 58e234f70..000000000
--- a/tempest/scenario/test_aggregates_basic_ops.py
+++ /dev/null
@@ -1,142 +0,0 @@
-# Copyright 2013 IBM Corp.
-# All Rights Reserved.
-#
-#    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 tempest.common import tempest_fixtures as fixtures
-from tempest.common import utils
-from tempest.lib.common.utils import data_utils
-from tempest.lib import decorators
-from tempest.scenario import manager
-
-
-class TestAggregatesBasicOps(manager.ScenarioTest):
-    """Creates an aggregate within an availability zone
-
-    Adds a host to the aggregate
-    Checks aggregate details
-    Updates aggregate's name
-    Removes host from aggregate
-    Deletes aggregate
-    """
-
-    credentials = ['primary', 'admin']
-
-    @classmethod
-    def setup_clients(cls):
-        super(TestAggregatesBasicOps, cls).setup_clients()
-        # Use admin client by default
-        cls.aggregates_client = cls.os_admin.aggregates_client
-        cls.services_client = cls.os_admin.services_client
-
-    def _create_aggregate(self, **kwargs):
-        aggregate = (self.aggregates_client.create_aggregate(**kwargs)
-                     ['aggregate'])
-        self.addCleanup(self.aggregates_client.delete_aggregate,
-                        aggregate['id'])
-        aggregate_name = kwargs['name']
-        availability_zone = kwargs['availability_zone']
-        self.assertEqual(aggregate['name'], aggregate_name)
-        self.assertEqual(aggregate['availability_zone'], availability_zone)
-        return aggregate
-
-    def _get_host_name(self):
-        # Find a host that has not been added to other availability zone,
-        # for one host can't be added to different availability zones.
-        svc_list = self.services_client.list_services(
-            binary='nova-compute')['services']
-        self.assertNotEmpty(svc_list)
-        hosts_available = []
-        for host in svc_list:
-            if (host['state'] == 'up' and host['status'] == 'enabled'):
-                hosts_available.append(host['host'])
-        aggregates = self.aggregates_client.list_aggregates()['aggregates']
-        hosts_in_zone = []
-        for agg in aggregates:
-            if agg['availability_zone']:
-                hosts_in_zone.extend(agg['hosts'])
-        hosts = [v for v in hosts_available if v not in hosts_in_zone]
-        if not hosts:
-            raise self.skipException("All hosts are already in other "
-                                     "availability zones, so can't add "
-                                     "host to aggregate. \nAggregates list: "
-                                     "%s" % aggregates)
-        return hosts[0]
-
-    def _add_host(self, aggregate_id, host):
-        aggregate = (self.aggregates_client.add_host(aggregate_id, host=host)
-                     ['aggregate'])
-        self.addCleanup(self._remove_host, aggregate['id'], host)
-        self.assertIn(host, aggregate['hosts'])
-
-    def _remove_host(self, aggregate_id, host):
-        aggregate = self.aggregates_client.remove_host(aggregate_id, host=host)
-        self.assertNotIn(host, aggregate['aggregate']['hosts'])
-
-    def _check_aggregate_details(self, aggregate, aggregate_name, azone,
-                                 hosts, metadata):
-        aggregate = (self.aggregates_client.show_aggregate(aggregate['id'])
-                     ['aggregate'])
-        self.assertEqual(aggregate_name, aggregate['name'])
-        self.assertEqual(azone, aggregate['availability_zone'])
-        self.assertEqual(hosts, aggregate['hosts'])
-        for meta_key in metadata:
-            self.assertIn(meta_key, aggregate['metadata'])
-            self.assertEqual(metadata[meta_key],
-                             aggregate['metadata'][meta_key])
-
-    def _set_aggregate_metadata(self, aggregate, meta):
-        aggregate = self.aggregates_client.set_metadata(aggregate['id'],
-                                                        metadata=meta)
-
-        for key in meta.keys():
-            self.assertEqual(meta[key],
-                             aggregate['aggregate']['metadata'][key])
-
-    def _update_aggregate(self, aggregate, aggregate_name,
-                          availability_zone):
-        aggregate = self.aggregates_client.update_aggregate(
-            aggregate['id'], name=aggregate_name,
-            availability_zone=availability_zone)['aggregate']
-        self.assertEqual(aggregate['name'], aggregate_name)
-        self.assertEqual(aggregate['availability_zone'], availability_zone)
-        return aggregate
-
-    @decorators.idempotent_id('cb2b4c4f-0c7c-4164-bdde-6285b302a081')
-    @decorators.attr(type='slow')
-    @utils.services('compute')
-    def test_aggregate_basic_ops(self):
-        self.useFixture(fixtures.LockFixture('availability_zone'))
-        az = 'foo_zone'
-        aggregate_name = data_utils.rand_name('aggregate-scenario')
-        aggregate = self._create_aggregate(name=aggregate_name,
-                                           availability_zone=az)
-
-        metadata = {'meta_key': 'meta_value'}
-        self._set_aggregate_metadata(aggregate, metadata)
-
-        host = self._get_host_name()
-        self._add_host(aggregate['id'], host)
-        self._check_aggregate_details(aggregate, aggregate_name, az, [host],
-                                      metadata)
-
-        aggregate_name = data_utils.rand_name('renamed-aggregate-scenario')
-        # Updating the name alone. The az must be specified again otherwise
-        # the tempest client would send None in the put body
-        aggregate = self._update_aggregate(aggregate, aggregate_name, az)
-
-        new_metadata = {'foo': 'bar'}
-        self._set_aggregate_metadata(aggregate, new_metadata)
-
-        self._check_aggregate_details(aggregate, aggregate['name'], az,
-                                      [host], new_metadata)