check whether requestcontext exists before access

common/lib/mitxmako/shortcuts.py

@@ -12,13 +12,16 @@
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
 
+import logging
+
+log = logging.getLogger("mitx.common.lib.mitxmako")
+
 from django.template import Context
 from django.http import HttpResponse
 
 from . import middleware
 from django.conf import settings
 
-
 def render_to_string(template_name, dictionary, context=None, namespace='main'):
     context_instance = Context(dictionary)
     # add dictionary to context_instance
@@ -27,8 +30,11 @@ def render_to_string(template_name, dictionary, context=None, namespace='main'):
     context_dictionary = {}
     context_instance['settings'] = settings
     context_instance['MITX_ROOT_URL'] = settings.MITX_ROOT_URL
-    for d in middleware.requestcontext:
-        context_dictionary.update(d)
+
+    # In various testing contexts, there might not be a current request context.
+    if middleware.requestcontext is not None:
+        for d in middleware.requestcontext:
+            context_dictionary.update(d)
     for d in context_instance:
         context_dictionary.update(d)
     if context: