diff --git a/tests/test_meds.py b/tests/test_meds.py
index 979996d..5b94529 100644
--- a/tests/test_meds.py
+++ b/tests/test_meds.py
@@ -375,7 +375,7 @@ def parse_labels_yaml(yaml_str: str) -> dict[str, pl.DataFrame]:
 
 WANT_EMPTY_WINDOW_SCHEMA = {"subject_id": pl.Int64}
 WANT_NON_EMPTY_WINDOW_SCHEMA = {
-    "subject_id": pl.UInt32,
+    "subject_id": pl.Int64,
     "prediction_time": pl.Datetime,
     "boolean_value": pl.Int64,
     "trigger": pl.Datetime,