LayoutTests/fast/loader/non-deferred-substitute-load.html

<p>This tests that using substitute load in combination with non-deferred main resource loading will not cause
assertions or duplicate loads, which can happen if the substitute document contains JavaScript-alerts.</p>
<script>
if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.setDeferMainResourceDataLoad(false);
    testRunner.queueLoadHTMLString("<script>if (typeof(hasBeenLoaded) != 'undefined') {" +
        "document.getElementById('result').innerHTML = 'FAILURE';" +
    "} else { " +
        "hasBeenLoaded = true; document.write('<div id=result>PASS</div>'); alert('Triggering bug through JS-alert'); }" +
    "<\/script>");
} else
    document.write('This test must be run by DumpRenderTree!')
</script>