<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <title>CSSOM - CSSGroupingRule - cssRules</title>
    <link rel="help" href="https://drafts.csswg.org/cssom/#the-cssgroupingrule-interface">
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script>
    function create(t) {
        var style = document.createElement('style');
        style.appendChild(document.createTextNode('@media all { * {} }'));
        document.head.appendChild(style);
        t.add_cleanup(function() {
            document.head.removeChild(style);
        });

        assert_true(!!style.sheet, 'setup - sheet defined');
        assert_equals(
            style.sheet.cssRules.length, 1, 'setup - grouping rule created'
        );
        assert_equals(
            style.sheet.cssRules[0].cssRules.length, 1, 'setup - rule created'
        );
        return style.sheet.cssRules[0];
    }

    test(function (t) {
        var groupingRule = create(t);
        groupingRule.cssRules.wptMarker = 'wpt';

        // `insertRule` is used to prompt non-conforming implementations to
        // create a new CSSRuleList object. Its behavior is verified by a
        // dedicated test and should not influence the result of this
        // particular test.
        try {
            groupingRule.insertRule('.foo {}', 0);
            groupingRule.insertRule('.bar {}', 0);
            groupingRule.insertRule('.baz {}', 0);
        } catch (err) {}

        assert_equals(groupingRule.cssRules.wptMarker, 'wpt');

        try {
            groupingRule.deleteRule('.foo {}', 0);
            groupingRule.deleteRule('.bar {}', 0);
            groupingRule.deleteRule('.baz {}', 0);
        } catch (err) {}

        assert_equals(groupingRule.cssRules.wptMarker, 'wpt');
    }, '[SameObject] is honored');
    </script>
</head>
</html>