ementsFromPoint(' + x + ',' + y + ')';
  var sequence = eval(query);
  assert_equals(nodeListToString(sequence), nodeListToString(expected), query);
}

function createBox(id) {
    var div = document.createElement('div');
    div.id = id;
    div.style.width = '100px';
    div.style.height = '10px';
    return div;
}

function centerX(element) {
    return element.offsetLeft + element.offsetWidth / 2;
}

function centerY(element) {
    return element.offsetTop + element.offsetHeight / 2;
}

var shadowRoot =