Add set_default() method to fixture

Add a set_default() method to the fixture to allow it to be passed to
set_default() functions in other oslo libraries that expect to be given
a ConfigObj instance. This lets tests in one project use a fixture to
set defaults for options in code they don't own, and unset those
defaults when the test is cleaned up.

Change-Id: Ifa9e6e2ab4ab4f93a7dc22d786ee6fd6ae7224ae

oslo_config/fixture.py

@@ -177,3 +177,27 @@ class Config(fixtures.Fixture):
 
         self.conf.default_config_files = config_files
         self.conf.reload_config_files()
+
+    def set_default(self, name, default, group=None):
+        """Set a default value for an option.
+
+        This method is not necessarily meant to be invoked
+        directly. It is here to allow the set_defaults() functions in
+        various Oslo libraries to work with a Config fixture instead
+        of a ConfigOpts instance.
+
+        Use it like::
+
+            class MyTest(testtools.TestCase):
+
+                def setUp(self):
+                    super(MyTest, self).setUp()
+                    self.conf = self.useFixture(fixture.Config())
+
+                def test_something(self):
+                    some_library.set_defaults(self.conf, name='value')
+                    some_library.do_something_exciting()
+
+        """
+        self.conf.set_default(name, default, group)
+        self.addCleanup(self.conf.clear_default, name, group)

oslo_config/tests/test_fixture.py

@@ -29,79 +29,79 @@ class ConfigTestCase(base.BaseTestCase):
         config_fixture.setUp()
         config_fixture.register_opt(cfg.StrOpt(
             'testing_option', default='initial_value'))
-        return (config_fixture, conf)
+        return config_fixture
 
     def test_overridden_value(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
-        self.assertEqual(conf.get('testing_option'), 'initial_value')
+        self.assertEqual(f.conf.get('testing_option'), 'initial_value')
         f.config(testing_option='changed_value')
-        self.assertEqual(conf.get('testing_option'),
+        self.assertEqual('changed_value',
                          f.conf.get('testing_option'))
 
     def test_cleanup(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         f.config(testing_option='changed_value')
         self.assertEqual(f.conf.get('testing_option'),
                          'changed_value')
         f.conf.reset()
-        self.assertEqual(conf.get('testing_option'), 'initial_value')
+        self.assertEqual(f.conf.get('testing_option'), 'initial_value')
 
     def test_register_option(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         opt = cfg.StrOpt('new_test_opt', default='initial_value')
         f.register_opt(opt)
-        self.assertEqual(conf.get('new_test_opt'),
+        self.assertEqual(f.conf.get('new_test_opt'),
                          opt.default)
 
     def test_register_options(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         opt1 = cfg.StrOpt('first_test_opt', default='initial_value_1')
         opt2 = cfg.StrOpt('second_test_opt', default='initial_value_2')
         f.register_opts([opt1, opt2])
-        self.assertEqual(conf.get('first_test_opt'), opt1.default)
+        self.assertEqual(f.conf.get('first_test_opt'), opt1.default)
-        self.assertEqual(conf.get('second_test_opt'), opt2.default)
+        self.assertEqual(f.conf.get('second_test_opt'), opt2.default)
 
     def test_cleanup_unregister_option(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         opt = cfg.StrOpt('new_test_opt', default='initial_value')
         f.register_opt(opt)
-        self.assertEqual(conf.get('new_test_opt'),
+        self.assertEqual(f.conf.get('new_test_opt'),
                          opt.default)
         f.cleanUp()
-        self.assertRaises(cfg.NoSuchOptError, conf.get, 'new_test_opt')
+        self.assertRaises(cfg.NoSuchOptError, f.conf.get, 'new_test_opt')
 
     def test_register_cli_option(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         opt = cfg.StrOpt('new_test_opt', default='initial_value')
         f.register_cli_opt(opt)
-        self.assertEqual(conf.get('new_test_opt'),
+        self.assertEqual(f.conf.get('new_test_opt'),
                          opt.default)
 
     def test_register_cli_options(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         opt1 = cfg.StrOpt('first_test_opt', default='initial_value_1')
         opt2 = cfg.StrOpt('second_test_opt', default='initial_value_2')
         f.register_cli_opts([opt1, opt2])
-        self.assertEqual(conf.get('first_test_opt'), opt1.default)
+        self.assertEqual(f.conf.get('first_test_opt'), opt1.default)
-        self.assertEqual(conf.get('second_test_opt'), opt2.default)
+        self.assertEqual(f.conf.get('second_test_opt'), opt2.default)
 
     def test_cleanup_unregister_cli_option(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         opt = cfg.StrOpt('new_test_opt', default='initial_value')
         f.register_cli_opt(opt)
-        self.assertEqual(conf.get('new_test_opt'),
+        self.assertEqual(f.conf.get('new_test_opt'),
                          opt.default)
         f.cleanUp()
-        self.assertRaises(cfg.NoSuchOptError, conf.get, 'new_test_opt')
+        self.assertRaises(cfg.NoSuchOptError, f.conf.get, 'new_test_opt')
 
     def test_load_raw_values(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
         f.load_raw_values(first_test_opt='loaded_value_1',
                           second_test_opt='loaded_value_2')
 
         # Must not be registered.
-        self.assertRaises(cfg.NoSuchOptError, conf.get, 'first_test_opt')
+        self.assertRaises(cfg.NoSuchOptError, f.conf.get, 'first_test_opt')
-        self.assertRaises(cfg.NoSuchOptError, conf.get, 'second_test_opt')
+        self.assertRaises(cfg.NoSuchOptError, f.conf.get, 'second_test_opt')
 
         opt1 = cfg.StrOpt('first_test_opt', default='initial_value_1')
         opt2 = cfg.StrOpt('second_test_opt', default='initial_value_2')
@@ -109,38 +109,38 @@ class ConfigTestCase(base.BaseTestCase):
         f.register_opt(opt1)
         f.register_opt(opt2)
 
-        self.assertEqual(conf.first_test_opt, 'loaded_value_1')
+        self.assertEqual(f.conf.first_test_opt, 'loaded_value_1')
-        self.assertEqual(conf.second_test_opt, 'loaded_value_2')
+        self.assertEqual(f.conf.second_test_opt, 'loaded_value_2')
 
         # Cleanup.
         f.cleanUp()
 
         # Must no longer be registered.
-        self.assertRaises(cfg.NoSuchOptError, conf.get, 'first_test_opt')
+        self.assertRaises(cfg.NoSuchOptError, f.conf.get, 'first_test_opt')
-        self.assertRaises(cfg.NoSuchOptError, conf.get, 'second_test_opt')
+        self.assertRaises(cfg.NoSuchOptError, f.conf.get, 'second_test_opt')
 
         # Even when registered, must be default.
         f.register_opt(opt1)
         f.register_opt(opt2)
-        self.assertEqual(conf.first_test_opt, 'initial_value_1')
+        self.assertEqual(f.conf.first_test_opt, 'initial_value_1')
-        self.assertEqual(conf.second_test_opt, 'initial_value_2')
+        self.assertEqual(f.conf.second_test_opt, 'initial_value_2')
 
     def test_assert_default_files_cleanup(self):
         """Assert that using the fixture forces a clean list."""
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
-        self.assertNotIn('default_config_files', conf)
+        self.assertNotIn('default_config_files', f.conf)
 
         config_files = ['./test_fixture.conf']
         f.set_config_files(config_files)
 
-        self.assertEqual(conf.default_config_files, config_files)
+        self.assertEqual(f.conf.default_config_files, config_files)
         f.cleanUp()
 
-        self.assertNotIn('default_config_files', conf)
+        self.assertNotIn('default_config_files', f.conf)
 
     def test_load_custom_files(self):
-        f, conf = self._make_fixture()
+        f = self._make_fixture()
-        self.assertNotIn('default_config_files', conf)
+        self.assertNotIn('default_config_files', f.conf)
         config_files = ['./oslo_config/tests/test_fixture.conf']
         f.set_config_files(config_files)
 
@@ -150,5 +150,34 @@ class ConfigTestCase(base.BaseTestCase):
         f.register_opt(opt1)
         f.register_opt(opt2)
 
-        self.assertEqual('loaded_value_1', conf.get('first_test_opt'))
+        self.assertEqual('loaded_value_1', f.conf.get('first_test_opt'))
-        self.assertEqual('loaded_value_2', conf.get('second_test_opt'))
+        self.assertEqual('loaded_value_2', f.conf.get('second_test_opt'))
+
+    def test_set_default(self):
+        f = self._make_fixture()
+        opt = cfg.StrOpt('new_test_opt', default='initial_value')
+        # Register the option directly so it is not cleaned up by the
+        # fixture.
+        f.conf.register_opt(opt)
+        f.set_default(
+            name='new_test_opt',
+            default='alternate_value',
+        )
+        self.assertEqual('alternate_value', f.conf.new_test_opt)
+        f.cleanUp()
+        self.assertEqual('initial_value', f.conf.new_test_opt)
+
+    def test_set_default_group(self):
+        f = self._make_fixture()
+        opt = cfg.StrOpt('new_test_opt', default='initial_value')
+        # Register the option directly so it is not cleaned up by the
+        # fixture.
+        f.conf.register_opt(opt, group='foo')
+        f.set_default(
+            name='new_test_opt',
+            default='alternate_value',
+            group='foo',
+        )
+        self.assertEqual('alternate_value', f.conf.foo.new_test_opt)
+        f.cleanUp()
+        self.assertEqual('initial_value', f.conf.foo.new_test_opt)