Make readonly field tests use exception from oslo.versionedobjects

This cleans up a tactical change in the previous patch by removing the
readonly exception from nova's module and modifying the tests that check
for this behavior to catch the library's exception directly.

Related to blueprint use-oslo-objects

Change-Id: I49ef7f10ea73744e886d95423e49f86c8be93258

nova/exception.py

@@ -28,7 +28,6 @@ import sys
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import excutils
-from oslo_versionedobjects import exception as ovo_exc
 import six
 import webob.exc
 
@@ -1520,11 +1519,6 @@ class IncompatibleObjectVersion(NovaException):
                 'maximum supported version is: %(supported)s')
 
 
-# FIXME(danms): Remove this and convert existing object tests to catch
-# the oslo_versionedobjects exception themselves
-ReadOnlyFieldError = ovo_exc.ReadOnlyFieldError
-
-
 class ObjectActionError(NovaException):
     msg_fmt = _('Object action %(action)s failed because: %(reason)s')
 

nova/tests/unit/objects/test_compute_node.py

@@ -15,6 +15,7 @@
 import mock
 from oslo_serialization import jsonutils
 from oslo_utils import timeutils
+from oslo_versionedobjects import exception as ovo_exc
 
 from nova import db
 from nova import exception
@@ -307,7 +308,7 @@ class _TestComputeNodeObject(object):
     def test_set_id_failure(self, db_mock):
         compute = compute_node.ComputeNode(context=self.context)
         compute.create()
-        self.assertRaises(exception.ReadOnlyFieldError, setattr,
+        self.assertRaises(ovo_exc.ReadOnlyFieldError, setattr,
                           compute, 'id', 124)
 
     def test_destroy(self):

nova/tests/unit/objects/test_security_group_rule.py

@@ -14,8 +14,9 @@
 
 import mock
 
+from oslo_versionedobjects import exception as ovo_exc
+
 from nova import db
-from nova import exception
 from nova import objects
 from nova.tests.unit.objects import test_objects
 from nova.tests.unit.objects import test_security_group
@@ -81,7 +82,7 @@ class _TestSecurityGroupRuleObject(object):
     def test_set_id_failure(self, db_mock):
         rule = objects.SecurityGroupRule(context=self.context)
         rule.create()
-        self.assertRaises(exception.ReadOnlyFieldError, setattr,
+        self.assertRaises(ovo_exc.ReadOnlyFieldError, setattr,
                           rule, 'id', 124)
 
 

nova/tests/unit/objects/test_service.py

@@ -14,6 +14,7 @@
 
 import mock
 from oslo_utils import timeutils
+from oslo_versionedobjects import exception as ovo_exc
 
 from nova import db
 from nova import exception
@@ -138,7 +139,7 @@ class _TestServiceObject(object):
     def test_set_id_failure(self, db_mock):
         service_obj = service.Service(context=self.context)
         service_obj.create()
-        self.assertRaises(exception.ReadOnlyFieldError, setattr,
+        self.assertRaises(ovo_exc.ReadOnlyFieldError, setattr,
                           service_obj, 'id', 124)
 
     def _test_destroy(self):