--- a/tests/test-diffdir	Thu Dec 07 11:22:17 2006 +0100
+++ b/tests/test-diffdir	Thu Dec 07 14:15:11 2006 -0200
@@ -13,3 +13,8 @@
 
 echo foo > a
 hg diff --nodates
+
+hg diff -r ""
+hg diff -r tip -r ""
+
+true