--- a/tests/test-revset.t	Thu Sep 10 23:25:10 2015 +0900
+++ b/tests/test-revset.t	Thu Sep 10 23:29:55 2015 +0900
@@ -353,6 +353,9 @@
   $ log 'date('
   hg: parse error at 5: not a prefix: end
   [255]
+  $ log 'date("\xy")'
+  hg: parse error: invalid \x escape
+  [255]
   $ log 'date(tip)'
   abort: invalid date: 'tip'
   [255]