LayoutTests/fast/dom/Window/window-open-top.html

<script>
if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
}
window.open("resources/destination.html", "_top");
</script>
<p>If you can still see this text, then the test of window.open(URL, "_top") has failed.</p>