--- a/tests/test-revset.t	Sat Jan 10 13:14:00 2015 +0900
+++ b/tests/test-revset.t	Sun Jan 25 20:20:27 2015 +0900
@@ -477,6 +477,10 @@
   hg: parse error: rev expects a number
   [255]
 
+Test null revision
+  $ log 'ancestors(null)'
+  -1
+
   $ log 'outgoing()'
   8
   9