third_party/blink/web_tests/editing/selection/last-empty-inline.html

<div>
To test this manually, press mouse button below the '!' and drag the mouse to the comma between "Hello" and "world!". It's OK if "world!" is selected.
</div>

<div id="result" style="width: 200px;">
<span>Hello,</span><span id="world">world!</span><br><span style="padding-left: 200px; padding-bottom: 200px; background-color: blue; height: 200px;"></span>
</div>

<script>
if (window.testRunner) {
    testRunner.dumpAsText();

    var world = document.getElementById("world");
    var endX = world.offsetLeft;
    var startX = endX + world.offsetWidth;
    var endY = world.offsetTop;
    var startY = endY + 50;

    eventSender.mouseMoveTo(startX, startY);
    eventSender.mouseDown();
    eventSender.mouseMoveTo(startX, startY);
    eventSender.mouseMoveTo(endX, endY);
    eventSender.mouseUp();

    var result = document.getElementById("result");
    if (window.getSelection() == "world!") {
        result.style.backgroundColor = "green";
        result.innerHTML = "PASS";
    } else
        result.innerHTML = "FAILED: the selection was " + window.getSelection();
}
</script>