diff -r 07f09995e857 -r ae95853c250a tests/test-amend.t
--- a/tests/test-amend.t	Tue Sep 12 11:18:35 2017 -0400
+++ b/tests/test-amend.t	Mon Sep 11 18:07:29 2017 +0200
@@ -85,6 +85,14 @@
   nothing changed
   [1]
 
+  $ hg amend -d "0 0"
+  nothing changed
+  [1]
+
+  $ hg amend -d "Thu Jan 01 00:00:00 1970 UTC"
+  nothing changed
+  [1]
+
 Matcher and metadata options
 
   $ echo 3 > C