diff --git a/src/platform/tests/platform.c b/src/platform/tests/platform.c
index 8a680c521b..9d2f970a24 100644
--- a/src/platform/tests/platform.c
+++ b/src/platform/tests/platform.c
@@ -532,6 +532,9 @@ parse_ip_address (int family, char *str, gpointer address, int *plen)
 {
 	char *endptr;
 
+	if (plen)
+		*plen = 0;
+
 	if (plen) {
 		char *ptr = strchr (str, '/');
 		if (ptr) {