--- a/tests/test-histedit-non-commute.t	Tue Mar 31 23:25:26 2020 +0900
+++ b/tests/test-histedit-non-commute.t	Thu Apr 09 15:44:21 2020 -0400
@@ -300,4 +300,7 @@
      summary:     Initial commit
   
 
+An invalid editor shouldn't leave the user in a broken state:
+  $ EDITOR=totally-not-a-thing-unsensible-editor-value hg histedit 4
+
   $ cd ..