1 files changed, 3 insertions, 1 deletions
diff --git a/tests/storage/databases/main/test_receipts.py b/tests/storage/databases/main/test_receipts.py
index 68026e2830..ac77aec003 100644
--- a/tests/storage/databases/main/test_receipts.py
+++ b/tests/storage/databases/main/test_receipts.py
@@ -168,7 +168,9 @@ class ReceiptsBackgroundUpdateStoreTestCase(HomeserverTestCase):
                     {"stream_id": 6, "event_id": "$some_event"},
                 ],
                 (self.other_room_id, "m.read", self.user_id): [
-                    {"stream_id": 7, "event_id": "$some_event"}
+                    # It is possible for stream IDs to be duplicated.
+                    {"stream_id": 7, "event_id": "$some_event"},
+                    {"stream_id": 7, "event_id": "$some_event"},
                 ],
             },
             expected_unique_receipts={