diff --git a/tests/test-diffdir b/tests/test-diffdir
--- a/tests/test-diffdir
+++ b/tests/test-diffdir
@@ -3,7 +3,7 @@
 hg init
 touch a
 hg add a
-hg ci -m "a" -d "0 0"
+hg ci -m "a" -d "1000000 0"
 
 echo 123 > b
 hg add b