';
        return array(
            array('',        ''),
            array('',                        ''),
            array('',    ''),
            array('',                      ''),
        );
    }
    /**
     * @dataProvider getTestCandidate()
     */
    public function testCollapseEmptyTagsForBug21177($original, $expected)
    {
        $this->assertEquals($expected, XML_Util::collapseEmptyTags($original, XML_UTIL_COLLAPSE_ALL), "Failed bugcheck.");
    }
}