diff --git a/backend/tests/test_detect_blocking_io_static.py b/backend/tests/test_detect_blocking_io_static.py
index 142f02e7d1..9985b7099f 100644
--- a/backend/tests/test_detect_blocking_io_static.py
+++ b/backend/tests/test_detect_blocking_io_static.py
@@ -246,7 +246,7 @@ def test_json_output_uses_concise_review_record_schema(tmp_path: Path, capsys) -
         {
             "priority": "HIGH",
             "location": {
-                "path": str(source_file),
+                "path": source_file.as_posix(),
                 "line": 4,
                 "column": 5,
                 "function": "handler",