diff --git a/barbican/api/hooks.py b/barbican/api/hooks.py
index fcb314465..5b502e898 100644
--- a/barbican/api/hooks.py
+++ b/barbican/api/hooks.py
@@ -29,7 +29,7 @@ from barbican.model import repositories
 class JSONErrorHook(pecan.hooks.PecanHook):
     def on_error(self, state, exc):
         if isinstance(exc, webob.exc.HTTPError):
-            exc.body = jsonutils.dumps({
+            exc.body = jsonutils.dump_as_bytes({
                 'code': exc.status_int,
                 'title': exc.title,
                 'description': exc.detail
diff --git a/tox.ini b/tox.ini
index 29d1fd4d8..a203d6842 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,6 +29,7 @@ commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasen
 commands =
     /usr/bin/find . -type f -name "*.pyc" -delete
     python -m testtools.run \
+        barbican.tests.api.controllers.test_cas \
         barbican.tests.api.controllers.test_versions \
         barbican.tests.api.middleware.test_context \
         barbican.tests.api.middleware.test_simple \