1 files changed, 21 insertions, 0 deletions
diff --git a/tests/rest/client/test_sync.py b/tests/rest/client/test_sync.py
index b085c50356..ae16184828 100644
--- a/tests/rest/client/test_sync.py
+++ b/tests/rest/client/test_sync.py
@@ -948,3 +948,24 @@ class ExcludeRoomTestCase(unittest.HomeserverTestCase):
 
         self.assertNotIn(self.excluded_room_id, channel.json_body["rooms"]["invite"])
         self.assertIn(self.included_room_id, channel.json_body["rooms"]["invite"])
+
+    def test_incremental_sync(self) -> None:
+        """Tests that activity in the room is properly filtered out of incremental
+        syncs.
+        """
+        channel = self.make_request("GET", "/sync", access_token=self.tok)
+        self.assertEqual(channel.code, 200, channel.result)
+        next_batch = channel.json_body["next_batch"]
+
+        self.helper.send(self.excluded_room_id, tok=self.tok)
+        self.helper.send(self.included_room_id, tok=self.tok)
+
+        channel = self.make_request(
+            "GET",
+            f"/sync?since={next_batch}",
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self.assertNotIn(self.excluded_room_id, channel.json_body["rooms"]["join"])
+        self.assertIn(self.included_room_id, channel.json_body["rooms"]["join"])