--- a/tests/check_yaml.c
+++ b/tests/check_yaml.c
@@ -426,6 +426,7 @@ main(int argc, char *argv[]) {
   yaml_event_delete(&event);
 
   char *tables_list = malloc(sizeof(char) * 512);
+  tables_list[0] = '\0';
   read_tables(&parser, tables_list);
 
   if (!yaml_parser_parse(&parser, &event) ||
