chore(neutron-understack): switch oslo_config overrides to a fixture

Rather than patching the global scoped oslo_config, switch to using a
fixture which resets between tests to ensure that things are cleaned up
appropriately. This will be necessary when we no longer initialize
oslo_config in the global/import scope of the module. While moving this
it pointed out an issue with one of the tests missing a mock which
attempted to hit the DB, which now couldn't be initialized because we
didn't setup our configs because the data had the wrong types which is
being fixed in this as well.

Author: cardoe

python/neutron-understack/neutron_understack/tests/conftest.py

@@ -22,7 +22,9 @@
 from neutron_lib import constants as p_const
 from neutron_lib.api.definitions import portbindings
 from neutron_lib.callbacks.events import DBEventPayload
+from oslo_config import fixture as config_fixture
 
+from neutron_understack import config as understack_config
 from neutron_understack.ironic import IronicClient
 from neutron_understack.neutron_understack_mech import UnderstackDriver
 from neutron_understack.tests.helpers import Ml2PluginNoInit
@@ -276,7 +278,7 @@ def ironic_client(mocker) -> IronicClient:
 
 
 @pytest.fixture
-def understack_driver(ironic_client) -> UnderstackDriver:
+def understack_driver(oslo_config, ironic_client) -> UnderstackDriver:
     driver = UnderstackDriver()
     driver.undersync = Undersync("auth_token", "api_url")
     driver.ironic_client = ironic_client
@@ -341,18 +343,29 @@ def port_db_payload(network) -> DBEventPayload:
 
 
 @pytest.fixture
-def ml2_understack_conf(mocker, ucvni_group_id) -> None:
-    mocker.patch(
-        "neutron_understack.neutron_understack_mech.cfg.CONF.ml2_understack.ucvni_group",
-        str(ucvni_group_id),
+def oslo_config():
+    """CONF from oslo_config is global but we need to override it sometimes."""
+    conf_fixture = config_fixture.Config()
+    conf_fixture.setUp()
+    # register the ml2_understack options
+    understack_config.register_ml2_understack_opts(conf_fixture.conf)
+    yield conf_fixture
+    conf_fixture.cleanUp()
+
+
+@pytest.fixture
+def ml2_understack_conf(oslo_config, ucvni_group_id) -> None:
+    oslo_config.config(
+        ucvni_group=str(ucvni_group_id),
+        group="ml2_understack",
     )
-    mocker.patch(
-        "neutron_understack.neutron_understack_mech.cfg.CONF.ml2_understack.network_node_switchport_uuid",
-        "a27f7260-a7c5-4f0c-ac70-6258b026d368",
+    oslo_config.config(
+        network_node_switchport_uuid="a27f7260-a7c5-4f0c-ac70-6258b026d368",
+        group="ml2_understack",
     )
-    mocker.patch(
-        "neutron_understack.neutron_understack_mech.cfg.CONF.ml2_understack.undersync_dry_run",
-        False,
+    oslo_config.config(
+        undersync_dry_run=False,
+        group="ml2_understack",
     )
 
 

python/neutron-understack/neutron_understack/tests/test_trunk.py

@@ -336,14 +336,23 @@ class TestCheckSubportsSegmentationId:
     def test_when_trunk_id_is_network_node_trunk_id(
         self,
         mocker,
+        oslo_config,
         understack_trunk_driver,
         trunk_id,
     ):
-        mocker.patch(
-            "oslo_config.cfg.CONF.ml2_understack.network_node_trunk_uuid",
-            trunk_id,
+        oslo_config.config(
+            network_node_trunk_uuid=str(trunk_id),
+            group="ml2_understack",
+        )
+        # Mock to ensure the function returns early and doesn't call this
+        allowed_ranges_mock = mocker.patch(
+            "neutron_understack.utils.allowed_tenant_vlan_id_ranges"
+        )
+        result = understack_trunk_driver._check_subports_segmentation_id(
+            [], str(trunk_id)
         )
-        result = understack_trunk_driver._check_subports_segmentation_id([], trunk_id)
+        # Should not call allowed_tenant_vlan_id_ranges because it returns early
+        allowed_ranges_mock.assert_not_called()
         assert result is None
 
     def test_when_segmentation_id_is_in_allowed_range(

python/neutron-understack/neutron_understack/tests/test_utils.py

@@ -189,10 +189,11 @@ class TestAllowedTenantVlanIdRanges:
     def test_multiple_non_overlapping_ranges(
         self,
         mocker,
+        oslo_config,
     ):
-        mocker.patch(
-            "oslo_config.cfg.CONF.ml2_understack.default_tenant_vlan_id_range",
-            [1, 2000],
+        oslo_config.config(
+            default_tenant_vlan_id_range=[1, 2000],
+            group="ml2_understack",
         )
         mocker.patch(
             "neutron_understack.utils.fetch_vlan_network_segment_ranges",
@@ -205,10 +206,11 @@ def test_multiple_non_overlapping_ranges(
     def test_multiple_overlapping_ranges(
         self,
         mocker,
+        oslo_config,
     ):
-        mocker.patch(
-            "oslo_config.cfg.CONF.ml2_understack.default_tenant_vlan_id_range",
-            [1, 2000],
+        oslo_config.config(
+            default_tenant_vlan_id_range=[1, 2000],
+            group="ml2_understack",
         )
         mocker.patch(
             "neutron_understack.utils.fetch_vlan_network_segment_ranges",
@@ -221,10 +223,11 @@ def test_multiple_overlapping_ranges(
     def test_single_range(
         self,
         mocker,
+        oslo_config,
     ):
-        mocker.patch(
-            "oslo_config.cfg.CONF.ml2_understack.default_tenant_vlan_id_range",
-            [1, 2000],
+        oslo_config.config(
+            default_tenant_vlan_id_range=[1, 2000],
+            group="ml2_understack",
         )
         mocker.patch(
             "neutron_understack.utils.fetch_vlan_network_segment_ranges",