diff --git a/src/test-iter.cc b/src/test-iter.cc
index 7ce6d8f..10db975 100644
--- a/src/test-iter.cc
+++ b/src/test-iter.cc
@@ -272,7 +272,7 @@
   hb_repeat (7u);
   hb_repeat (nullptr);
   hb_repeat (vl);
-  assert ((hb_range (10) | hb_take (3)).len () == 3);
+  assert (hb_len (hb_range (10) | hb_take (3)) == 3);
   assert (hb_range (9).len () == 9);
   assert (hb_range (2, 9).len () == 7);
   assert (hb_range (2, 9, 3).len () == 3);