add tests

servo · mrmiywj · Jun 7, 2016 · Jun 9, 2016 · Jun 10, 2016 · Jun 10, 2016
commit d29ceebb150aaa6460b16811009c57d68b07223f
diff --git a/tests/wpt/web-platform-tests/html/semantics/forms/the-form-element/form-indexed-element.html b/tests/wpt/web-platform-tests/html/semantics/forms/the-form-element/form-indexed-element.html
@@ -20,5 +20,7 @@
   var form = document.getElementById("form");
   assert_equals(form[0], document.getElementById("r1"));
   assert_equals(form[1], document.getElementById("r2"));
+  assert_equals(form[2], undefined);
+  assert_equals(form[-1], undefined);
   }, "form.elements should be accessed correctly by index")
 </script>