diff --git a/tests/api/stubs.c b/tests/api/stubs.c
index 9f49c9d..7f1e898 100644
--- a/tests/api/stubs.c
+++ b/tests/api/stubs.c
@@ -46,6 +46,10 @@ char *pr_fs_encode_path(pool *p, const char *path) {
   return (char *) path;
 }
 
+int pr_fs_get_usable_fd(int fd) {
+  return -1;
+}
+
 void pr_log_debug(int level, const char *fmt, ...) {
 }