1 files changed, 1 insertions, 1 deletions
diff --git a/tests/test_federation.py b/tests/test_federation.py
index 87a16d7d7a..c2f12c2741 100644
--- a/tests/test_federation.py
+++ b/tests/test_federation.py
@@ -95,7 +95,7 @@ class MessageAcceptTests(unittest.HomeserverTestCase):
         prev_events that said event references.
         """
 
-        def post_json(destination, path, data, headers=None, timeout=0):
+        async def post_json(destination, path, data, headers=None, timeout=0):
             # If it asks us for new missing events, give them NOTHING
             if path.startswith("/_matrix/federation/v1/get_missing_events/"):
                 return {"events": []}