LayoutTests/http/tests/loading/preload-css-test.html

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

var results=[];
function checkForPreload(url, shouldbe) {
    var preloaded = internals.isPreloaded(url);
    if ((preloaded && shouldbe) || (!preloaded && !shouldbe))
        results.push("PASS\n");
    else
        results.push("FAIL\n");
}
function printResults(){
    for(var i = 0; i < results.length; i++)
        document.getElementsByTagName("body")[0].appendChild(document.createTextNode(results[i]));
}
    
</script>
<script src="http://127.0.0.1:8000/resources/slow-script.pl?delay=1000"></script>
<script>
checkForPreload("resources/big_mq.css", true);
checkForPreload("resources/small_mq.css", false);
</script>
<link href="resources/big_mq.css" rel="stylesheet" media="screen and (min-width: 800px)">
<link href="resources/small_mq.css" rel="stylesheet" media="screen and (max-width: 799px)">
<script src="http://127.0.0.1:8000/resources/slow-script.pl?delay=1000"></script>

<body>
<p>Preload scanner should preload only the relevant MQ external CSS</p>
<script>
printResults();
</script>