,
                      ["0", "1", "2"])
  assert_array_equals(Object.getOwnPropertyNames(el.attributes),
                      ["0", "1", "2", "a", "b"])
  for (var propName of Object.getOwnPropertyNames(el.attributes)) {
    assert_true(el.attributes[propName] instanceof Attr,
                "el.attributes has an Attr for property name " + propName);
  }
}, "Own property correctness with non-namespaced attribute before same-name namespaced one");

test(function() {
  var el = document.createElement("div"