--- a/tests/test-touch.t	Tue Jan 22 12:54:43 2019 -0500
+++ b/tests/test-touch.t	Thu Apr 11 22:41:41 2019 +0200
@@ -161,3 +161,12 @@
        rewritten(.*) as [0-9a-f]{12} using touch by test (.*) (re)
          note: testing with no successor
   
+
+Public phase
+
+  $ hg phase --public -r 2
+  $ hg touch 2
+  abort: cannot touch public changesets: * (glob)
+  (see 'hg help phases' for details)
+  [255]
+  $ hg touch --duplicate 2