diff --git a/tests/test-empty-file b/tests/test-empty-file
--- a/tests/test-empty-file
+++ b/tests/test-empty-file
@@ -22,4 +22,4 @@ hg merge 1
 # empty file that came from rev 1.
 hg status
 hg commit -m merge -d '1000000 0'
-hg manifest tip
+hg manifest --debug tip