diff --git a/test/mocked_fsrc.c b/test/mocked_fsrc.c
index 362470b..9f76ad5 100644
--- a/test/mocked_fsrc.c
+++ b/test/mocked_fsrc.c
@@ -156,6 +156,7 @@ void mfs_free(IsoFileSource *src)
 }
 
 IsoFileSourceIface mfs_class = {
+    0,
     mfs_get_path,
     mfs_get_name,
     mfs_lstat,