diff --git a/testing/test_conftest.py b/testing/test_conftest.py
index 5d5407717..6c8072019 100644
--- a/testing/test_conftest.py
+++ b/testing/test_conftest.py
@@ -382,6 +382,7 @@ def test_my_option(pytester):
         encoding="utf-8",
     )
     result = pytester.runpytest("--my_option=None", str(testdir))
+    assert result.ret == 0
     result.stdout.fnmatch_lines(["*1 passed*"])