Adopt oslotest BaseTestCase as a base class for DietTestCase

This will make us more in line with other projects in terms of testing
API. It also allows to remove some duplicate code from base test classes
for Neutron, leaving just Neutron specific fixture setup there.

Note: we don't add a new dependency because the library is already used
in some of database functional tests through oslo.db base test classes.

Change-Id: Ifec6cce386d8b024605496026c8469200f3c002b
Closes-Bug: #1531484

neutron/tests/base.py

@@ -18,7 +18,6 @@
 
 import contextlib
 import gc
-import logging as std_logging
 import os
 import os.path
 import random
@@ -31,8 +30,8 @@ from oslo_concurrency.fixture import lockutils
 from oslo_config import cfg
 from oslo_messaging import conffixture as messaging_conffixture
 from oslo_utils import strutils
+from oslotest import base
 import six
-import testtools
 
 from neutron._i18n import _
 from neutron.agent.linux import external_process
@@ -52,7 +51,6 @@ from neutron.tests import tools
 
 CONF = cfg.CONF
 CONF.import_opt('state_path', 'neutron.common.config')
-LOG_FORMAT = "%(asctime)s %(levelname)8s [%(name)s] %(message)s"
 
 ROOTDIR = os.path.dirname(__file__)
 ETCDIR = os.path.join(ROOTDIR, 'etc')
@@ -100,10 +98,6 @@ def bool_from_env(key, strict=False, default=False):
     return strutils.bool_from_string(value, strict=strict, default=default)
 
 
-def get_test_timeout(default=0):
-    return int(os.environ.get('OS_TEST_TIMEOUT', 0))
-
-
 def sanitize_log_path(path):
     # Sanitize the string so that its log path is shell friendly
     return path.replace(' ', '-').replace('(', '_').replace(')', '_')
@@ -122,7 +116,7 @@ class AttributeDict(dict):
         raise AttributeError(_("Unknown attribute '%s'.") % name)
 
 
-class DietTestCase(testtools.TestCase):
+class DietTestCase(base.BaseTestCase):
     """Same great taste, less filling.
 
     BaseTestCase is responsible for doing lots of plugin-centric setup
@@ -147,39 +141,14 @@ class DietTestCase(testtools.TestCase):
         # Make sure we see all relevant deprecation warnings when running tests
         self.useFixture(tools.WarningsFixture())
 
-        if bool_from_env('OS_DEBUG'):
-            _level = std_logging.DEBUG
-        else:
-            _level = std_logging.INFO
-        capture_logs = bool_from_env('OS_LOG_CAPTURE')
-        if not capture_logs:
-            std_logging.basicConfig(format=LOG_FORMAT, level=_level)
-        self.log_fixture = self.useFixture(
-            fixtures.FakeLogger(
-                format=LOG_FORMAT,
-                level=_level,
-                nuke_handlers=capture_logs,
-            ))
-
-        test_timeout = get_test_timeout()
-        if test_timeout == -1:
-            test_timeout = 0
-        if test_timeout > 0:
-            self.useFixture(fixtures.Timeout(test_timeout, gentle=True))
-
-        # If someone does use tempfile directly, ensure that it's cleaned up
-        self.useFixture(fixtures.NestedTempfile())
-        self.useFixture(fixtures.TempHomeDir())
-
+        # NOTE(ihrachys): oslotest already sets stopall for cleanup, but it
+        # does it using six.moves.mock (the library was moved into
+        # unittest.mock in Python 3.4). So until we switch to six.moves.mock
+        # everywhere in unit tests, we can't remove this setup. The base class
+        # is used in 3party projects, so we would need to switch all of them to
+        # six before removing the cleanup callback from here.
         self.addCleanup(mock.patch.stopall)
 
-        if bool_from_env('OS_STDOUT_CAPTURE'):
-            stdout = self.useFixture(fixtures.StringStream('stdout')).stream
-            self.useFixture(fixtures.MonkeyPatch('sys.stdout', stdout))
-        if bool_from_env('OS_STDERR_CAPTURE'):
-            stderr = self.useFixture(fixtures.StringStream('stderr')).stream
-            self.useFixture(fixtures.MonkeyPatch('sys.stderr', stderr))
-
         self.addOnException(self.check_for_systemexit)
         self.orig_pid = os.getpid()
 
@@ -271,16 +240,6 @@ class BaseTestCase(DietTestCase):
     def setUp(self):
         super(BaseTestCase, self).setUp()
 
-        # suppress all but errors here
-        capture_logs = bool_from_env('OS_LOG_CAPTURE')
-        self.useFixture(
-            fixtures.FakeLogger(
-                name='neutron.api.extensions',
-                format=LOG_FORMAT,
-                level=std_logging.ERROR,
-                nuke_handlers=capture_logs,
-            ))
-
         self.useFixture(lockutils.ExternalLockFixture())
 
         cfg.CONF.set_override('state_path', self.get_default_temp_dir().path)

neutron/tests/functional/agent/linux/test_ovsdb_monitor.py

@@ -26,7 +26,6 @@ from oslo_config import cfg
 
 from neutron.agent.linux import ovsdb_monitor
 from neutron.agent.linux import utils
-from neutron.tests import base as tests_base
 from neutron.tests.common import net_helpers
 from neutron.tests.functional.agent.linux import base as linux_base
 from neutron.tests.functional import base as functional_base
@@ -85,10 +84,7 @@ class TestSimpleInterfaceMonitor(BaseMonitorTest):
 
         self.monitor = ovsdb_monitor.SimpleInterfaceMonitor()
         self.addCleanup(self.monitor.stop)
-        # In case a global test timeout isn't set or disabled, use a
-        # value that will ensure the monitor has time to start.
-        timeout = max(tests_base.get_test_timeout(), 60)
-        self.monitor.start(block=True, timeout=timeout)
+        self.monitor.start(block=True, timeout=60)
 
     def test_has_updates(self):
         utils.wait_until_true(lambda: self.monitor.has_updates)

neutron/tests/unit/plugins/ml2/drivers/test_helpers.py

@@ -13,16 +13,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import fixtures
 import mock
 from oslo_db import exception as exc
-from oslo_log import log as logging
 from sqlalchemy.orm import query
 
 import neutron.db.api as db
-from neutron.plugins.ml2.drivers import helpers
 from neutron.plugins.ml2.drivers import type_vlan
-from neutron.tests import base
 from neutron.tests.unit import testlib_api
 
 
@@ -43,12 +39,6 @@ class HelpersTest(testlib_api.SqlTestCase):
         self.driver.network_vlan_ranges = NETWORK_VLAN_RANGES
         self.driver._sync_vlan_allocations()
         self.session = db.get_session()
-        self.useFixture(
-            fixtures.FakeLogger(
-                name=helpers.__name__,
-                format=base.LOG_FORMAT,
-                level=logging.DEBUG
-            ))
 
     def check_raw_segment(self, expected, observed):
         for key, value in expected.items():