diff --git a/tests/test-merge5 b/tests/test-merge5
--- a/tests/test-merge5
+++ b/tests/test-merge5
@@ -12,9 +12,13 @@ hg commit -m"comment #1" -d "1000000 0"
 hg update 0
 rm b
 hg commit -A -m"comment #2" -d "1000000 0"
+
+echo This is file a > a
 # in theory, we shouldn't need the "-y" below, but it prevents
 # this test from hanging when "hg update" erroneously prompts the
 # user for "keep or delete"
+hg update -y 1 # should fail (unclean repo)
+hg revert a
 hg update -y 1
 
 exit 0