/**
  * @return Sitemap\Sitemapindex
  */
 protected function getRoot()
 {
     if (null === $this->root) {
         $this->root = new Sitemap\Sitemapindex();
         foreach ($this->urlsets as $urlset) {
             $this->root->addSitemap($urlset);
         }
     }
     return $this->root;
 }
 public function testToXml()
 {
     $sitemapindex = new Sitemap\Sitemapindex();
     $xml = $sitemapindex->toXml();
     $this->assertXmlStringEqualsXmlString('<?xml version="1.0" encoding="UTF-8"?><sitemapindex xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/siteindex.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"></sitemapindex>', $xml);
 }