Add testutils.ConfPatcher and use it in tests

The tests were modifying a global ConfigOpts object, without
resetting the old value, which could affect other tests as well.
The new ConfPatcher class can be used both as a context manager
and as a decorator, making sure that the old value of configuration
option is set back after exiting from the decorated function or from
the context manager.

Change-Id: If23bf225207977e0e313dc806d53bca8a40215d6

cloudbaseinit/tests/metadata/services/test_ec2service.py

@@ -31,7 +31,6 @@ CONF = cfg.CONF
 class EC2ServiceTest(unittest.TestCase):
 
     def setUp(self):
-        CONF.set_override('retry_count_interval', 0)
         self._service = ec2service.EC2Service()
 
     @mock.patch('cloudbaseinit.utils.network.check_metadata_ip_route')

cloudbaseinit/tests/metadata/services/test_httpservice.py

@@ -31,7 +31,6 @@ CONF = cfg.CONF
 class HttpServiceTest(unittest.TestCase):
 
     def setUp(self):
-        CONF.set_override('retry_count_interval', 0)
         self._httpservice = httpservice.HttpService()
 
     @mock.patch('cloudbaseinit.utils.network.check_metadata_ip_route')

cloudbaseinit/tests/metadata/services/test_maasservice.py

@@ -25,6 +25,7 @@ from oslo.config import cfg
 from six.moves.urllib import error
 
 from cloudbaseinit.metadata.services import base
+from cloudbaseinit.tests import testutils
 from cloudbaseinit.utils import x509constants
 
 if sys.version_info < (3, 0):
@@ -47,7 +48,7 @@ class MaaSHttpServiceTest(unittest.TestCase):
     @mock.patch("cloudbaseinit.metadata.services.maasservice.MaaSHttpService"
                 "._get_data")
     def _test_load(self, mock_get_data, ip):
-        CONF.set_override('maas_metadata_url', ip)
+        with testutils.ConfPatcher('maas_metadata_url', ip):
             response = self._maasservice.load()
             if ip is not None:
                 mock_get_data.assert_called_once_with(
@@ -124,7 +125,7 @@ class MaaSHttpServiceTest(unittest.TestCase):
                 "._get_response")
     def test_get_data(self, mock_get_response, mock_Request,
                       mock_get_oauth_headers):
-        CONF.set_override('maas_metadata_url', '196.254.196.254')
+        with testutils.ConfPatcher('maas_metadata_url', '196.254.196.254'):
             fake_path = os.path.join('fake', 'path')
             mock_get_oauth_headers.return_value = 'fake headers'
             response = self._maasservice._get_data(path=fake_path)

cloudbaseinit/tests/plugins/windows/test_createuser.py

@@ -22,6 +22,7 @@ from oslo.config import cfg
 
 from cloudbaseinit.plugins import base
 from cloudbaseinit.plugins.windows import createuser
+from cloudbaseinit.tests import testutils
 
 CONF = cfg.CONF
 
@@ -38,12 +39,12 @@ class CreateUserPluginTests(unittest.TestCase):
         mock_osutils.generate_random_password.assert_called_once_with(14)
         self.assertEqual('fake password', response)
 
+    @testutils.ConfPatcher('groups', ['Admins'])
     @mock.patch('cloudbaseinit.osutils.factory.get_os_utils')
     @mock.patch('cloudbaseinit.plugins.windows.createuser.CreateUserPlugin'
                 '._get_password')
     def _test_execute(self, mock_get_password, mock_get_os_utils,
                       user_exists=True):
-        CONF.set_override('groups', ['Admins'])
         shared_data = {}
         mock_token = mock.MagicMock()
         mock_osutils = mock.MagicMock()

cloudbaseinit/tests/plugins/windows/test_extendvolumes.py

@@ -20,9 +20,8 @@ try:
     import unittest.mock as mock
 except ImportError:
     import mock
-from oslo.config import cfg
 
-CONF = cfg.CONF
+from cloudbaseinit.tests import testutils
 
 
 class ExtendVolumesPluginTests(unittest.TestCase):
@@ -187,7 +186,7 @@ class ExtendVolumesPluginTests(unittest.TestCase):
         self.assertEqual(['fake packs'], response)
 
     def test_get_volumes_to_extend(self):
-        CONF.set_override('volumes_to_extend', '1')
+        with testutils.ConfPatcher('volumes_to_extend', '1'):
             response = self._extend_volumes._get_volumes_to_extend()
             self.assertEqual([1], response)
 
@@ -200,7 +199,6 @@ class ExtendVolumesPluginTests(unittest.TestCase):
                 'ExtendVolumesPlugin._extend_volumes')
     def test_execute(self, mock_extend_volumes, mock_query_packs,
                      mock_query_providers, mock_load_vds_service):
-        CONF.set_override('volumes_to_extend', '1')
         mock_svc = mock.MagicMock()
         fake_providers = ['fake providers']
         fake_packs = ['fake packs']
@@ -210,6 +208,7 @@ class ExtendVolumesPluginTests(unittest.TestCase):
         mock_query_providers.return_value = fake_providers
         mock_query_packs.return_value = fake_packs
 
+        with testutils.ConfPatcher('volumes_to_extend', '1'):
             self._extend_volumes.execute(mock_service, fake_data)
 
         mock_query_providers.assert_called_once_with(mock_svc)

cloudbaseinit/tests/plugins/windows/test_licensing.py

@@ -19,13 +19,11 @@ try:
     import unittest.mock as mock
 except ImportError:
     import mock
-from oslo.config import cfg
 
 from cloudbaseinit import exception
 from cloudbaseinit.plugins import base
 from cloudbaseinit.plugins.windows import licensing
-
+from cloudbaseinit.tests import testutils
-CONF = cfg.CONF
 
 
 class WindowsLicensingPluginTests(unittest.TestCase):
@@ -86,9 +84,9 @@ class WindowsLicensingPluginTests(unittest.TestCase):
                       activate_windows):
         mock_osutils = mock.MagicMock()
         run_slmgr_calls = [mock.call(mock_osutils, ['/dlv'])]
-        CONF.set_override('activate_windows', activate_windows)
         mock_get_os_utils.return_value = mock_osutils
 
+        with testutils.ConfPatcher('activate_windows', activate_windows):
             response = self._licensing.execute(service=None, shared_data=None)
 
         mock_get_os_utils.assert_called_once_with()

cloudbaseinit/tests/plugins/windows/test_localscripts.py

@@ -22,9 +22,7 @@ except ImportError:
 
 from cloudbaseinit.plugins import base
 from cloudbaseinit.plugins.windows import localscripts
-from oslo.config import cfg
+from cloudbaseinit.tests import testutils
-
-CONF = cfg.CONF
 
 
 class LocalScriptsPluginTests(unittest.TestCase):
@@ -45,18 +43,20 @@ class LocalScriptsPluginTests(unittest.TestCase):
             sorted(os.path.join(fake_path, f) for f in fake_file_list),
             response)
 
+    @testutils.ConfPatcher('local_scripts_path',
+                           mock.sentinel.mock_local_scripts_path)
     @mock.patch('cloudbaseinit.plugins.windows.localscripts'
                 '.LocalScriptsPlugin._get_files_in_dir')
     @mock.patch('cloudbaseinit.plugins.windows.fileexecutils.exec_file')
     def test_execute(self, mock_exec_file, mock_get_files_in_dir):
         mock_service = mock.MagicMock()
         fake_path = os.path.join('fake', 'path')
-        CONF.set_override('local_scripts_path', True)
 
         mock_get_files_in_dir.return_value = [fake_path]
 
         response = self._localscripts.execute(mock_service, shared_data=None)
 
-        mock_get_files_in_dir.assert_called_once_with(CONF.local_scripts_path)
+        mock_get_files_in_dir.assert_called_once_with(
+            mock.sentinel.mock_local_scripts_path)
         mock_exec_file.assert_called_once_with(fake_path)
         self.assertEqual((base.PLUGIN_EXECUTION_DONE, False), response)

cloudbaseinit/tests/plugins/windows/test_ntpclient.py

@@ -18,15 +18,13 @@ try:
     import unittest.mock as mock
 except ImportError:
     import mock
-from oslo.config import cfg
 
 from cloudbaseinit import exception
 from cloudbaseinit.plugins import base
 from cloudbaseinit.plugins.windows import ntpclient
+from cloudbaseinit.tests import testutils
 from cloudbaseinit.utils import dhcp
 
-CONF = cfg.CONF
-
 
 class NTPClientPluginTests(unittest.TestCase):
 
@@ -105,6 +103,7 @@ class NTPClientPluginTests(unittest.TestCase):
                                             fail_service_start=False,
                                             patch_check_os_version=False)
 
+    @testutils.ConfPatcher('ntp_use_dhcp_config', True)
     @mock.patch('cloudbaseinit.osutils.factory.get_os_utils')
     @mock.patch('cloudbaseinit.utils.dhcp.get_dhcp_options')
     @mock.patch('cloudbaseinit.plugins.windows.ntpclient.NTPClientPlugin.'
@@ -119,7 +118,6 @@ class NTPClientPluginTests(unittest.TestCase):
         # see the expected result.
         mock_unpack_ntp_hosts.side_effect = original_unpack_hosts
 
-        CONF.set_override('ntp_use_dhcp_config', True)
         mock_service = mock.MagicMock()
         mock_osutils = mock.MagicMock()
         mock_options_data = mock.MagicMock()

cloudbaseinit/tests/plugins/windows/test_sethostname.py

@@ -18,13 +18,11 @@ try:
     import unittest.mock as mock
 except ImportError:
     import mock
-from oslo.config import cfg
 
 from cloudbaseinit.plugins import base
 from cloudbaseinit.plugins.windows import sethostname
 from cloudbaseinit.tests.metadata import fake_json_response
-
+from cloudbaseinit.tests import testutils
-CONF = cfg.CONF
 
 
 class SetHostNamePluginPluginTests(unittest.TestCase):
@@ -34,6 +32,7 @@ class SetHostNamePluginPluginTests(unittest.TestCase):
         self.fake_data = fake_json_response.get_fake_metadata_json(
             '2013-04-04')
 
+    @testutils.ConfPatcher('netbios_host_name_compatibility', True)
     @mock.patch('platform.node')
     @mock.patch('cloudbaseinit.osutils.factory.get_os_utils')
     def _test_execute(self, mock_get_os_utils, mock_node, hostname_exists=True,
@@ -52,7 +51,6 @@ class SetHostNamePluginPluginTests(unittest.TestCase):
         else:
             mock_service.get_host_name.return_value = None
 
-        CONF.set_override('netbios_host_name_compatibility', True)
         mock_get_os_utils.return_value = mock_osutils
 
         if hostname_exists is True:

cloudbaseinit/tests/plugins/windows/test_setuserpassword.py

@@ -23,6 +23,7 @@ from oslo.config import cfg
 from cloudbaseinit.plugins import constants
 from cloudbaseinit.plugins.windows import setuserpassword
 from cloudbaseinit.tests.metadata import fake_json_response
+from cloudbaseinit.tests import testutils
 
 CONF = cfg.CONF
 
@@ -74,7 +75,6 @@ class SetUserPasswordPluginTests(unittest.TestCase):
         mock_service = mock.MagicMock()
         mock_osutils = mock.MagicMock()
         mock_service.get_admin_password.return_value = 'Passw0rd'
-        CONF.set_override('inject_user_password', inject_password)
         mock_osutils.generate_random_password.return_value = 'Passw0rd'
         response = self._setpassword_plugin._get_password(mock_service,
                                                           mock_osutils)
@@ -85,9 +85,11 @@ class SetUserPasswordPluginTests(unittest.TestCase):
         self.assertEqual('Passw0rd', response)
 
     def test_get_password_inject_true(self):
+        with testutils.ConfPatcher('inject_user_password', True):
             self._test_get_password(inject_password=True)
 
     def test_get_password_inject_false(self):
+        with testutils.ConfPatcher('inject_user_password', False):
             self._test_get_password(inject_password=False)
 
     @mock.patch('cloudbaseinit.plugins.windows.setuserpassword.'

cloudbaseinit/tests/plugins/windows/test_sshpublickeys.py

@@ -19,14 +19,12 @@ try:
     import unittest.mock as mock
 except ImportError:
     import mock
-from oslo.config import cfg
 
 from cloudbaseinit import exception
 from cloudbaseinit.plugins import base
 from cloudbaseinit.plugins.windows import sshpublickeys
 from cloudbaseinit.tests.metadata import fake_json_response
-
+from cloudbaseinit.tests import testutils
-CONF = cfg.CONF
 
 
 class SetUserSSHPublicKeysPluginTests(unittest.TestCase):
@@ -36,6 +34,7 @@ class SetUserSSHPublicKeysPluginTests(unittest.TestCase):
         self.fake_data = fake_json_response.get_fake_metadata_json(
             '2013-04-04')
 
+    @testutils.ConfPatcher('username', mock.sentinel.username)
     @mock.patch('cloudbaseinit.osutils.factory.get_os_utils')
     @mock.patch('os.path')
     @mock.patch('os.makedirs')
@@ -45,7 +44,6 @@ class SetUserSSHPublicKeysPluginTests(unittest.TestCase):
         mock_osutils = mock.MagicMock()
         fake_shared_data = 'fake data'
         mock_service.get_public_keys.return_value = self.fake_data
-        CONF.set_override('username', 'fake user')
         mock_get_os_utils.return_value = mock_osutils
         mock_osutils.get_user_home.return_value = user_home
         mock_os_path.exists.return_value = False
@@ -61,7 +59,8 @@ class SetUserSSHPublicKeysPluginTests(unittest.TestCase):
                 response = self._set_ssh_keys_plugin.execute(mock_service,
                                                              fake_shared_data)
                 mock_service.get_public_keys.assert_called_with()
-                mock_osutils.get_user_home.assert_called_with('fake user')
+                mock_osutils.get_user_home.assert_called_with(
+                    mock.sentinel.username)
                 self.assertEqual(2, mock_os_path.join.call_count)
                 mock_os_makedirs.assert_called_once_with(mock_os_path.join())
 

cloudbaseinit/tests/testutils.py

@@ -13,18 +13,24 @@
 #    under the License.
 
 import contextlib
+import functools
 import logging as base_logging
 import os
 import shutil
 import tempfile
 
+from oslo.config import cfg
+
 from cloudbaseinit.openstack.common import log as logging
 
 
+CONF = cfg.CONF
+
 __all__ = (
     'create_tempfile',
     'create_tempdir',
     'LogSnatcher',
+    'ConfPatcher',
 )
 
 
@@ -108,3 +114,34 @@ class LogSnatcher(object):
     def __exit__(self, *args):
         self._logger.handlers.remove(self._snatch_handler)
         self._logger.logger.setLevel(self._previous_level)
+
+
+class ConfPatcher(object):
+    """Override the configuration for the given key, with the given value.
+
+    This class can be used both as a context manager and as a decorator.
+    """
+    # TODO(cpopa): mock.patch.dict would have been a better solution
+    #              but oslo.config.cfg doesn't support item
+    #              assignment.
+
+    def __init__(self, key, value, conf=CONF):
+        self._original_value = conf.get(key)
+        self._key = key
+        self._value = value
+        self._conf = conf
+
+    def __call__(self, func, *args, **kwargs):
+        def _wrapped_f(*args, **kwargs):
+            with self:
+                return func(*args, **kwargs)
+
+        functools.update_wrapper(_wrapped_f, func)
+        return _wrapped_f
+
+    def __enter__(self):
+        self._conf.set_override(self._key, self._value)
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self._conf.set_override(self._key, self._original_value)

cloudbaseinit/tests/utils/test_log.py

@@ -38,6 +38,7 @@ class SerialPortHandlerTests(unittest.TestCase):
 
         self.log = importlib.import_module("cloudbaseinit.utils.log")
 
+        self._old_value = CONF.get('logging_serial_port_settings')
         CONF.set_override('logging_serial_port_settings', "COM1,115200,N,8")
         self._serial_port_handler = self.log.SerialPortHandler()
         self._unicode_stream = self._serial_port_handler._UnicodeToBytesStream(
@@ -46,6 +47,7 @@ class SerialPortHandlerTests(unittest.TestCase):
 
     def tearDown(self):
         self._module_patcher.stop()
+        CONF.set_override('logging_serial_port_settings', self._old_value)
 
     def test_init(self):
         mock_Serial = self._serial.Serial