<!doctype html>
<html>
<head>
<script src="../../resources/js-test-pre.js"></script>
<style>
#test-root * {
    background-color: red;
}
</style>
<style id="style">
</style>
</head>
<body>
    <div style="display:none" id="test-root">
        <testcase id="testcase1"></testcase>
        <testcase id="testcase2"></testcase>
        <testcase id="testcase3"></testcase>
        <testcase id="testcase4"></testcase>
        <testcase id="testcase5"></testcase>
    </div>
</body>
<script>
description('Test cases of :nth-last-child() matching only the last child.');

function testQuerySelector(selector, expectedIds) {
    shouldBe("document.querySelectorAll('" + selector + "').length", '' + expectedIds.length);
    for (var i = 0; i < expectedIds.length; ++i)
        shouldBeEqualToString("document.querySelectorAll('" + selector + "')[" + i + "].id", expectedIds[i]);
}

function testStyling(selector, expectedIds) {
    var stylingElement = document.getElementById("style");
    stylingElement.innerHTML = '' + selector + ' { background-color: rgb(10, 100, 200); }';

    var allTestCases = document.querySelectorAll("#test-root *");
    for (var i = 0; i < allTestCases.length; ++i) {
        var expectMatch = expectedIds.indexOf(allTestCases[i].id) >= 0;
        shouldBeEqualToString('getComputedStyle(document.querySelectorAll("#test-root *")[' + i + ']).backgroundColor', expectMatch ? 'rgb(10, 100, 200)' : 'rgb(255, 0, 0)');
    }

    stylingElement.innerHTML = '';
}

function testSelector(selector, expectedIds) {
    debug("Testing \"" + selector + "\"");
    testQuerySelector("#test-root " + selector, expectedIds);
    testStyling("#test-root " + selector, expectedIds);
    debug("");
}

// All of thoses only match the last child, they are synonym with :last-child.
testSelector(":nth-last-child(1)", ["testcase5"]);
testSelector(":nth-last-child(+1)", ["testcase5"]);
testSelector(":nth-last-child(-n+1)", ["testcase5"]);
testSelector(":nth-last-child(-2n+1)", ["testcase5"]);
testSelector(":nth-last-child(-3n+1)", ["testcase5"]);

// The above combined with other :nth-last-child().
testSelector(":nth-last-child(odd):nth-last-child(1):nth-last-child(2n+1)", ["testcase5"]);
testSelector(":nth-last-child(odd):nth-last-child(+1):nth-last-child(2n+1)", ["testcase5"]);
testSelector(":nth-last-child(odd):nth-last-child(-n+1):nth-last-child(2n+1)", ["testcase5"]);
testSelector(":nth-last-child(odd):nth-last-child(-2n+1):nth-last-child(2n+1)", ["testcase5"]);
testSelector(":nth-last-child(odd):nth-last-child(-3n+1):nth-last-child(2n+1)", ["testcase5"]);

// Some related counter examples.
testSelector(":nth-last-child(-n-1)", []);

testSelector(":nth-last-child(n+1)", ["testcase1", "testcase2", "testcase3", "testcase4", "testcase5"]);
testSelector(":nth-last-child(n-1)", ["testcase1", "testcase2", "testcase3", "testcase4", "testcase5"]);
</script>
<script src="../../resources/js-test-post.js"></script>
</html>