diff --git a/tests/test_benchmarks_web_fileresponse.py b/tests/test_benchmarks_web_fileresponse.py
index cf2ebe94af3..f1ad62e1cb5 100644
--- a/tests/test_benchmarks_web_fileresponse.py
+++ b/tests/test_benchmarks_web_fileresponse.py
@@ -46,7 +46,8 @@ def test_simple_web_file_sendfile_fallback_response(
 
     async def handler(request: web.Request) -> web.FileResponse:
         transport = request.transport
-        transport._sendfile_compatible = False
+        assert transport is not None
+        transport._sendfile_compatible = False  # type: ignore
         return web.FileResponse(path=filepath)
 
     app = web.Application()