<!doctype html>
<html>
<head>
<script src="../../resources/js-test-pre.js"></script>
<style>
target {
    background-color: white;
}
target:nth-last-child(n+5) {
    background-color: rgb(1, 2, 3);
}
</style>
</head>
<body>
    <div id="with-renderer">
        <target class="element_1"></target>
        <target class="element_2"></target>
        <target class="element_3"></target>
        <target class="element_4"></target>
        <target class="element_5"></target>
    </div>
    <div id="without-renderer" style="display:none;">
        <target class="element_1"></target>
        <target class="element_2"></target>
        <target class="element_3"></target>
        <target class="element_4"></target>
        <target class="element_5"></target>
    </div>
</body>
<script>
description('Test style update of :nth-last-child() when the tree structure is modified.');

function testColor(classesThatShouldMatch) {
    var allTargets = document.querySelectorAll("target");
    for (var i = 0; i < allTargets.length; ++i) {
        var expectMath = classesThatShouldMatch.indexOf(allTargets[i].className) != -1;
        shouldBeEqualToString('getComputedStyle(document.querySelectorAll("target")[' + i + ']).backgroundColor', expectMath ? 'rgb(1, 2, 3)' : 'rgb(255, 255, 255)');
    }
}

function addElementAsFirstChild(tagName, className)
{
    var newElement = document.createElement(tagName);
    newElement.className = className;

    var withRenderer = document.getElementById("with-renderer");
    withRenderer.insertBefore(newElement, withRenderer.firstChild);

    var withoutRenderer = document.getElementById("without-renderer");
    withoutRenderer.insertBefore(newElement.cloneNode(), withoutRenderer.firstChild);
}

function removeElementsOfClass(className)
{
    var allElementsToRemove = document.querySelectorAll('.' + className);
    for (var i = 0; i < allElementsToRemove.length; ++i)
        allElementsToRemove[i].parentElement.removeChild(allElementsToRemove[i]);
}

debug("Initialy, only the first can match.");
testColor(["element_1"]);

debug("Adding an element &lt;target&gt; on top, we should now match 0 and 1.");
addElementAsFirstChild("target", "element_0")
testColor(["element_0", "element_1"]);

// Using nottarget is interesting because the ':nth-last-child()' part is not matched for those elements.
debug("Adding an element &lt;nottarget&gt; on top, we should now match -1, 0, 1.");
addElementAsFirstChild("nottarget", "element_-1")
testColor(["element_-1", "element_0", "element_1"]);

debug("Adding an element &lt;nottarget&gt; on top, we should now match -2, -1, 0, 1.");
addElementAsFirstChild("nottarget", "element_-2")
testColor(["element_-2", "element_-1", "element_0", "element_1"]);

debug("Adding an element &lt;target&gt; on top, we should now match -3, -2, -1, 0, 1.");
addElementAsFirstChild("target", "element_-3")
testColor(["element_-3", "element_-2", "element_-1", "element_0", "element_1"]);

debug("Adding an element &lt;nottarget&gt; on top, we should now match -4, -3, -2, -1, 0, 1.");
addElementAsFirstChild("nottarget", "element_-4")
testColor(["element_-4", "element_-3", "element_-2", "element_-1", "element_0", "element_1"]);

debug("Removing one of the &lt;nottarget&gt;, -2 should no longer match.");
removeElementsOfClass("element_-2");
testColor(["element_-4", "element_-3", "element_-1", "element_0", "element_1"]);

debug("Removing one of the &lt;target&gt;, -4 should no longer match.");
removeElementsOfClass("element_-4");
testColor(["element_-3", "element_-1", "element_0", "element_1"]);

debug("Removing one of the &lt;notarget&gt;, -1 should no longer match.");
removeElementsOfClass("element_-1");
testColor(["element_-3", "element_0", "element_1"]);

debug("Removing one of the &lt;target&gt;, -3 should no longer match.");
removeElementsOfClass("element_-3");
testColor(["element_0", "element_1"]);

debug("Removing one of the &lt;target&gt;, 0 should no longer match.");
removeElementsOfClass("element_0");
testColor(["element_1"]);

debug("Removing one of the &lt;target&gt;, there are only 4 siblings left, nothing can match.");
removeElementsOfClass("element_1");
testColor([]);

</script>
<script src="../../resources/js-test-post.js"></script>
</html>