<!DOCTYPE html>
<style>
    body { margin: 8px; -webkit-writing-mode: vertical-rl; }
    div.box { -webkit-box-sizing: border; border: solid blue; }
    div.shorter { width: 54px; }
    div.taller { width: 72px; }
</style>
<div style="width: 100px; height: 325px; -webkit-columns:6; -webkit-column-gap:5px; columns:6; column-gap:5px; column-fill:auto;">
    <div class="taller box"></div>
    <div class="taller box"></div>
    <div id="break-before" class="shorter box" style="-webkit-column-break-before: always;"></div>
    <div class="shorter box" style="-webkit-column-break-after: always;"></div>
    <div id="after-break" class="shorter box"></div>
    <div id="no-break" class="shorter box" style="-webkit-column-break-inside: avoid;"></div>
</div>
<pre id="console"></pre>
<script>
    if (window.testRunner)
        testRunner.dumpAsText();

    function log(message)
    {
        document.getElementById("console").appendChild(document.createTextNode(message + "\n"));
    }

    function testBoxColumn(id, expectedColumn) {
        var rect = document.getElementById(id).getBoundingClientRect();
        var actualPosition = Math.round(rect.top);
        var expectedPosition = 8 + (50 + 5) * expectedColumn;

        if (actualPosition == expectedPosition)
            log("PASS: '" + id + "' is in column " + expectedColumn);
        else
            log("FAIL: '" + id + "' is at position " + actualPosition + " instead of " + expectedPosition);
    }

    testBoxColumn("break-before", 2);
    testBoxColumn("after-break", 4);
    testBoxColumn("no-break", 5);
</script>