diff --git a/tests/jerry/N.delete.js b/tests/jerry/N.delete.js
index 1c82b9859..d90900f6a 100644
--- a/tests/jerry/N.delete.js
+++ b/tests/jerry/N.delete.js
@@ -21,6 +21,7 @@ assert (a[0] === 1);
 assert (delete a[0] === true);
 assert (a[0] == undefined);
 assert (delete 0 === true);
+assert (delete "0" === true);
 var b = {c:0};
 assert (b.c === 0);
 assert (delete b.c === true);