diff --git a/t/test-lib.sh b/t/test-lib.sh
index bdd9513b84..160479b81e 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -379,6 +379,11 @@ test_config () {
 	git config "$@"
 }
 
+test_config_global () {
+	test_when_finished "test_unconfig --global '$1'" &&
+	git config --global "$@"
+}
+
 # Use test_set_prereq to tell that a particular prerequisite is available.
 # The prerequisite can later be checked for in two ways:
 #