fter() without any argument.');

    test(function() {
        var parent = document.createElement('div');
        parent.appendChild(child);
        child.after(null);
        var expected = innerHTML + 'null';
        assert_equals(parent.innerHTML, expected);
    }, nodeName + '.after() with null as an argument.');

    test(function() {
        var parent = document.createElement('div');
        parent.appendChild(child);
        child.after(undefined);
        var expected = innerHTML + 'undefined';
  