diff --git a/tests/t_fticks.c b/tests/t_fticks.c
index c7c6ab6..b1d852a 100644
--- a/tests/t_fticks.c
+++ b/tests/t_fticks.c
@@ -2,6 +2,7 @@
 /* See LICENSE for licensing information. */
 
 #include <stdio.h>
+#include <string.h>
 #include <errno.h>
 #include "../radsecproxy.h"
 #include "../fticks_hashmac.h"