test cleanup: Use oslotest's Timeout fixture

Nova had its own copy of oslotest's Timeout fixture (probably predating
that one, actually). DRY it up.

A future change should be able to remove references to this fixture from
nova.test.TestCase by inheriting from oslotest.base.BaseTestCase instead
of testtools.TestCase. But we may or may not want to do the same for
NovaMigrationsCheckers subclasses (TestNovaMigrations*) since that would
pull in fixtures we don't care about (output and tempfile/tempdir).

Change-Id: I813a80fae306334abb653e6d3603eabe2d2332bf

nova/test.py

@@ -47,6 +47,7 @@ from oslo_utils import timeutils
 from oslo_versionedobjects import fixture as ovo_fixture
 from oslotest import mock_fixture
 from oslotest import moxstubout
+from oslotest import timeout
 import six
 from six.moves import builtins
 import testtools
@@ -177,9 +178,9 @@ class TestCase(testtools.TestCase):
     def setUp(self):
         """Run before each test method to initialize test environment."""
         super(TestCase, self).setUp()
-        self.useFixture(nova_fixtures.Timeout(
-            os.environ.get('OS_TEST_TIMEOUT', 0),
-            self.TIMEOUT_SCALING_FACTOR))
+        # The Timeout fixture picks up env.OS_TEST_TIMEOUT, defaulting to 0.
+        self.useFixture(timeout.Timeout(
+            scaling_factor=self.TIMEOUT_SCALING_FACTOR))
 
         self.useFixture(nova_fixtures.OpenStackSDKFixture())
 

nova/tests/fixtures.py

@@ -231,35 +231,6 @@ class OutputStreamCapture(fixtures.Fixture):
         return self.out._details["stdout"].as_text()
 
 
-class Timeout(fixtures.Fixture):
-    """Setup per test timeouts.
-
-    In order to avoid test deadlocks we support setting up a test
-    timeout parameter read from the environment. In almost all
-    cases where the timeout is reached this means a deadlock.
-
-    A class level TIMEOUT_SCALING_FACTOR also exists, which allows
-    extremely long tests to specify they need more time.
-    """
-
-    def __init__(self, timeout, scaling=1):
-        super(Timeout, self).__init__()
-        try:
-            self.test_timeout = int(timeout)
-        except ValueError:
-            # If timeout value is invalid do not set a timeout.
-            self.test_timeout = 0
-        if scaling >= 1:
-            self.test_timeout *= scaling
-        else:
-            raise ValueError('scaling value must be >= 1')
-
-    def setUp(self):
-        super(Timeout, self).setUp()
-        if self.test_timeout > 0:
-            self.useFixture(fixtures.Timeout(self.test_timeout, gentle=True))
-
-
 class DatabasePoisonFixture(fixtures.Fixture):
     def setUp(self):
         super(DatabasePoisonFixture, self).setUp()

nova/tests/unit/db/test_migrations.py

@@ -42,6 +42,7 @@ from oslo_db.sqlalchemy import enginefacade
 from oslo_db.sqlalchemy import test_fixtures
 from oslo_db.sqlalchemy import test_migrations
 from oslo_db.sqlalchemy import utils as oslodbutils
+from oslotest import timeout
 import sqlalchemy
 from sqlalchemy.engine import reflection
 import sqlalchemy.exc
@@ -96,13 +97,9 @@ class NovaMigrationsCheckers(test_migrations.ModelsMigrationsSync,
         self.useFixture(nova_fixtures.StandardLogging())
 
         super(NovaMigrationsCheckers, self).setUp()
-        # NOTE(rpodolyaka): we need to repeat the functionality of the base
-        # test case a bit here as this gets overridden by oslotest base test
-        # case and nova base test case cleanup must be the last one (as it
-        # deletes attributes of test case instances)
-        self.useFixture(nova_fixtures.Timeout(
-            os.environ.get('OS_TEST_TIMEOUT', 0),
-            self.TIMEOUT_SCALING_FACTOR))
+        # The Timeout fixture picks up env.OS_TEST_TIMEOUT, defaulting to 0.
+        self.useFixture(timeout.Timeout(
+            scaling_factor=self.TIMEOUT_SCALING_FACTOR))
         self.engine = enginefacade.writer.get_engine()
 
     def assertColumnExists(self, engine, table_name, column):

nova/tests/unit/test_fixtures.py

@@ -145,27 +145,6 @@ class TestLogging(testtools.TestCase):
         self.assertIn("at debug", stdlog.logger.output)
 
 
-class TestTimeout(testtools.TestCase):
-    """Tests for our timeout fixture.
-
-    Testing the actual timeout mechanism is beyond the scope of this
-    test, because it's a pretty clear pass through to fixtures'
-    timeout fixture, which tested in their tree.
-
-    """
-    def test_scaling(self):
-        # a bad scaling factor
-        self.assertRaises(ValueError, fixtures.Timeout, 1, 0.5)
-
-        # various things that should work.
-        timeout = fixtures.Timeout(10)
-        self.assertEqual(10, timeout.test_timeout)
-        timeout = fixtures.Timeout("10")
-        self.assertEqual(10, timeout.test_timeout)
-        timeout = fixtures.Timeout("10", 2)
-        self.assertEqual(20, timeout.test_timeout)
-
-
 class TestOSAPIFixture(testtools.TestCase):
     @mock.patch('nova.objects.Service.get_by_host_and_binary')
     @mock.patch('nova.objects.Service.create')