diff --git a/test/test_ls.py b/test/test_ls.py
index 43f6018..4a13e0a 100644
--- a/test/test_ls.py
+++ b/test/test_ls.py
@@ -1,6 +1,6 @@
 import json
 from unittest.mock import mock_open, patch
-from con_duct.suite.ls import _flatten_dict, load_duct_runs
+from con_duct.suite.ls import _flatten_dict, _restrict_row, load_duct_runs
 
 
 def test_load_duct_runs_sanity():
@@ -43,3 +43,12 @@ def test_flatten_dict():
     nested = {"a": {"b": 1, "c": 2}, "d": 3}
     result = _flatten_dict(nested)
     assert result == {"b": 1, "c": 2, "d": 3}
+
+
+def test_restrict_row():
+    row = {"prefix": "/test/path", "exit_code": 0, "extra": "ignore"}
+    fields = ["exit_code"]
+    result = _restrict_row(fields, row)
+    assert "prefix" in result
+    assert "exit_code" in result
+    assert "extra" not in result