LayoutTests/fast/forms/input-text-double-click.html

<input type="text" value="word another">
<p>Tests double-clicking on a word. If the test succeeds, the word "word" should be selected.</p>
<script>
onload = async () => {
    if (!window.testRunner)
        return;

    testRunner.waitUntilDone();

    if (window.eventSender) {
        await eventSender.asyncMouseMoveTo(15, 15);
        await eventSender.asyncMouseDown();
        await eventSender.asyncMouseUp();
        await eventSender.asyncMouseDown();
        await eventSender.asyncMouseUp();
    }

    testRunner.notifyDone();
}
</script>