diff --git a/neutron/tests/unit/objects/db/test_api.py b/neutron/tests/unit/objects/db/test_api.py
index beef8bc1f1f..da91546b30e 100644
--- a/neutron/tests/unit/objects/db/test_api.py
+++ b/neutron/tests/unit/objects/db/test_api.py
@@ -25,9 +25,6 @@ from neutron.tests import base as test_base
 from neutron.tests.unit import testlib_api
 
 
-PLUGIN_NAME = 'neutron.db.db_base_plugin_v2.NeutronDbPluginV2'
-
-
 class FakeModel(object):
     def __init__(self, *args, **kwargs):
         pass
@@ -39,12 +36,6 @@ class FakeObj(base.NeutronDbObject):
 
 class GetObjectsTestCase(test_base.BaseTestCase):
 
-    def setUp(self):
-        super(GetObjectsTestCase, self).setUp()
-        # TODO(ihrachys): revisit plugin setup once we decouple
-        # objects.db.objects.api from core plugin instance
-        self.setup_coreplugin(PLUGIN_NAME)
-
     def test_get_objects_pass_marker_obj_when_limit_and_marker_passed(self):
         ctxt = context.get_admin_context()
         marker = mock.sentinel.marker
diff --git a/neutron/tests/unit/objects/test_base.py b/neutron/tests/unit/objects/test_base.py
index 821b7f3d839..68498161a87 100644
--- a/neutron/tests/unit/objects/test_base.py
+++ b/neutron/tests/unit/objects/test_base.py
@@ -559,13 +559,8 @@ class _BaseObjectTestCase(object):
 
     _test_class = FakeNeutronDbObject
 
-    CORE_PLUGIN = 'neutron.db.db_base_plugin_v2.NeutronDbPluginV2'
-
     def setUp(self):
         super(_BaseObjectTestCase, self).setUp()
-        # TODO(ihrachys): revisit plugin setup once we decouple
-        # neutron.objects.db.api from core plugin instance
-        self.setup_coreplugin(self.CORE_PLUGIN)
         # make sure all objects are loaded and registered in the registry
         objects.register_objects()
         self.context = context.get_admin_context()
diff --git a/neutron/tests/unit/objects/test_subnet.py b/neutron/tests/unit/objects/test_subnet.py
index 2ace9cd6293..f3561705e53 100644
--- a/neutron/tests/unit/objects/test_subnet.py
+++ b/neutron/tests/unit/objects/test_subnet.py
@@ -148,8 +148,13 @@ class SubnetDbObjectTestCase(obj_test_base.BaseDbObjectTestCase,
 
     _test_class = subnet.Subnet
 
+    CORE_PLUGIN = 'neutron.db.db_base_plugin_v2.NeutronDbPluginV2'
+
     def setUp(self):
         super(SubnetDbObjectTestCase, self).setUp()
+        # set up plugin because some models used here require a plugin
+        # (specifically, rbac models and their get_valid_actions validators)
+        self.setup_coreplugin(self.CORE_PLUGIN)
         network_id = self._create_test_network_id()
         self.update_obj_fields(
             {'network_id': network_id,