diff --git a/tests/basics/nanbox_smallint.py b/tests/basics/nanbox_smallint.py
index 642ca77b37..167b196010 100644
--- a/tests/basics/nanbox_smallint.py
+++ b/tests/basics/nanbox_smallint.py
@@ -9,6 +9,7 @@ try:
     float(123)
     micropython.heap_unlock()
 except:
+    micropython.heap_unlock()
     print("SKIP")
     raise SystemExit