Add unit tests

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py

index a27029c678..bd91b9f018 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -307,7 +307,7 @@ class Filter(object):
             content = event.get("content", {})
             # check if there is a string url field in the content for filtering purposes
             contains_url = isinstance(content.get("url"), text_type)
-            labels = content.get(LabelsField)
+            labels = content.get(LabelsField, [])
 
         return self.check_fields(room_id, sender, ev_type, labels, contains_url)