diff --git a/openstack_dashboard/dashboards/project/vg_snapshots/tests.py b/openstack_dashboard/dashboards/project/vg_snapshots/tests.py
index d66185335c..d14709792b 100644
--- a/openstack_dashboard/dashboards/project/vg_snapshots/tests.py
+++ b/openstack_dashboard/dashboards/project/vg_snapshots/tests.py
@@ -71,11 +71,10 @@ class GroupSnapshotTests(test.TestCase):
                       args=[vg_snapshot.id])
         res = self.client.post(url, formData)
         self.assertNoFormErrors(res)
-        # There are a bunch of backslashes for formatting in the message from
-        # the response, so remove them when validating the error message.
-        self.assertIn('Unable to create group "%s" from snapshot.'
-                      % new_cg_name,
-                      res.cookies.output().replace('\\', ''))
+        self.assertCookieMessage(
+            res,
+            'Unable to create group "%s" from snapshot.' % new_cg_name,
+            'Expected failure.')
         self.assertRedirectsNoFollow(res, INDEX_URL)
 
         mock_group_snapshot_get.assert_called_once_with(
diff --git a/openstack_dashboard/dashboards/project/volume_groups/tests.py b/openstack_dashboard/dashboards/project/volume_groups/tests.py
index e5caffd291..d80b4fb42a 100644
--- a/openstack_dashboard/dashboards/project/volume_groups/tests.py
+++ b/openstack_dashboard/dashboards/project/volume_groups/tests.py
@@ -108,8 +108,7 @@ class VolumeGroupTests(test.TestCase):
         res = self.client.post(url, formData)
         self.assertNoFormErrors(res)
         self.assertRedirectsNoFollow(res, INDEX_URL)
-        self.assertIn("Unable to create group.",
-                      res.cookies.output())
+        self.assertCookieMessage(res, "Unable to create group.")
 
         self.mock_extension_supported.assert_called_once_with(
             test.IsHttpRequest(), 'AvailabilityZones')
diff --git a/openstack_dashboard/test/helpers.py b/openstack_dashboard/test/helpers.py
index 6d2292673e..19afd7c02d 100644
--- a/openstack_dashboard/test/helpers.py
+++ b/openstack_dashboard/test/helpers.py
@@ -24,6 +24,7 @@ import traceback
 from unittest import mock
 
 from django.conf import settings
+from django.contrib.messages.storage import cookie as cookie_storage
 from django.contrib.messages.storage import default_storage
 from django.core.handlers import wsgi
 from django.test.client import RequestFactory
@@ -38,6 +39,7 @@ from requests.packages.urllib3.connection import HTTPConnection
 
 from horizon import base
 from horizon import conf
+from horizon import exceptions
 from horizon.test import helpers as horizon_helpers
 from openstack_dashboard import api
 from openstack_dashboard import context_processors
@@ -438,6 +440,16 @@ class TestCase(horizon_helpers.TestCase):
                 len(errors), 0,
                 "No errors were found on the workflow")
 
+    def assertCookieMessage(self, response, expected_msg, detail_msg=None):
+        data = response.cookies["messages"]
+        storage = cookie_storage.CookieStorage(None)
+        messages = [m.message for m in storage._decode(data.value)]
+        if detail_msg is not None:
+            _expected = exceptions._append_detail(expected_msg, detail_msg)
+        else:
+            _expected = expected_msg
+        self.assertIn(_expected, messages)
+
 
 class BaseAdminViewTests(TestCase):
     """Sets an active user with the "admin" role.