diff --git a/tests/cfg/test_cfg.py b/tests/cfg/test_cfg.py
index ee2074b..e92ec1d 100644
--- a/tests/cfg/test_cfg.py
+++ b/tests/cfg/test_cfg.py
@@ -90,3 +90,9 @@ class TestConfig_e2e:
             "expecting default from config.spec (didnt get)"
         )
         assert cfg["app"]["sub_option"] == "def_sub", "expecting default for sub option"
+
+
+def test_canary_fails_only_on_newest_lane():
+    import sys
+
+    assert sys.version_info < (3, 14)