--- a/tests/test-fix.t	Tue Apr 27 14:59:45 2021 -0700
+++ b/tests/test-fix.t	Thu Feb 11 15:11:10 2021 -0800
@@ -1173,6 +1173,7 @@
   $ hg commit -m "second"
   $ hg --config experimental.evolution.allowunstable=False fix -r '.^'
   abort: cannot fix changeset with children
+  (see 'hg help evolution.instability')
   [10]
   $ hg fix -r '.^'
   1 new orphan changesets