diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index f3af10fb7e..5fd5494ef1 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1195,8 +1195,9 @@ test_must_fail () {
 		echo >&7 "test_must_fail: only 'git' is allowed: $*"
 		return 1
 	fi
-	"$@" 2>&7
-	exit_code=$?
+
+	exit_code=0; "$@" 2>&7 || exit_code=$?
+
 	if test $exit_code -eq 0 && ! list_contains "$_test_ok" success
 	then
 		echo >&4 "test_must_fail: command succeeded: $*"