--- a/tests/test-fileset.t	Thu Sep 10 23:29:55 2015 +0900
+++ b/tests/test-fileset.t	Thu Sep 10 23:32:36 2015 +0900
@@ -49,6 +49,9 @@
   $ fileset 'a* - a1'
   a2
   $ fileset 'a_b'
+  $ fileset '"\xy"'
+  hg: parse error: invalid \x escape
+  [255]
 
 Test files status