diff --git a/bindep.txt b/bindep.txt
index 22a288467ff..b196c8fff63 100644
--- a/bindep.txt
+++ b/bindep.txt
@@ -4,6 +4,7 @@ build-essential [platform:dpkg test]
 gcc [platform:rpm test]
 gettext [!platform:suse]
 gettext-runtime [platform:suse]
+graphviz [test]
 libffi-dev [platform:dpkg]
 libffi-devel [platform:redhat]
 libffi48-devel [platform:suse]
diff --git a/cinder/volume/qos_specs.py b/cinder/volume/qos_specs.py
index 4e334e7de1d..a86fe109bbe 100644
--- a/cinder/volume/qos_specs.py
+++ b/cinder/volume/qos_specs.py
@@ -40,13 +40,13 @@ def create(context, name, specs=None):
 
     Expected format of the input parameter:
 
-        .. code-block:: json
+       .. code-block:: python
 
-            {
-                'consumer': 'front-end',
-                'total_iops_sec': 1000,
-                'total_bytes_sec': 1024000
-            }
+          {
+             'consumer': 'front-end',
+             'total_iops_sec': 1000,
+             'total_bytes_sec': 1024000
+          }
 
     """
     # Validate the key-value pairs in the qos spec.
diff --git a/setup.cfg b/setup.cfg
index 723823b5599..6a519e39808 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -75,6 +75,7 @@ tempest.test_plugins =
 
 [build_sphinx]
 all_files = 1
+warning-is-error = 1
 build-dir = doc/build
 source-dir = doc/source