diff --git a/event_model/tests/test_run_router.py b/event_model/tests/test_run_router.py
index a6dbf541..b25b6391 100644
--- a/event_model/tests/test_run_router.py
+++ b/event_model/tests/test_run_router.py
@@ -218,7 +218,7 @@ def test_run_router_streams(tmp_path):
     stream_resource_doc, compose_stream_datum = compose_stream_resource(
         mimetype="image/tiff",
         data_key="det1",
-        uri="file://" + str(tmp_path) + "/test_streams",
+        uri="file://localhost" + str(tmp_path) + "/test_streams",
         parameters={},
     )
     docs.append(("stream_resource", stream_resource_doc))