diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index d169fb2f59..d0f4f3885d 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -177,6 +177,8 @@ debug () {
 #	Invoke "git commit" with --signoff
 #   --author <author>
 #	Invoke "git commit" with --author <author>
+#   --no-tag
+#	Do not tag the resulting commit
 #
 # This will commit a file with the given contents and the given commit
 # message, and tag the resulting commit with the given tag name.