ableOwnProps2(el.attributes),
                      ["0", "1", "2"])
  assert_array_equals(Object.getOwnPropertyNames(el.attributes),
                      ["0", "1", "2", "a:b", "c:d"])
  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 two namespaced attributes with the same name-with-prefix");

test(function() {
  var e