diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 9fd09dbe93..df443a981d 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -314,7 +314,7 @@ test_expect_success PERL 'setup change in subdirectory' '
 	git commit -m "added sub/sub" &&
 	echo test >>file &&
 	echo test >>sub/sub &&
-	git add . &&
+	git add file sub/sub &&
 	git commit -m "modified both"
 '