diff --git a/tests/plugins/test_debug.py b/tests/plugins/test_debug.py
index a58ff07..a553cd9 100644
--- a/tests/plugins/test_debug.py
+++ b/tests/plugins/test_debug.py
@@ -110,3 +110,8 @@ def test_stringify_cfm():
     )
     print(stringify_cfm(cfm))
     assert cfm_str in stringify_cfm(cfm)
+
+
+def test_stringify_cfm_can_stringify_none_cfm():
+    cfm_str = "CFM:\nNone"
+    assert cfm_str in stringify_cfm(None)