public function testSerializeXmlFormat()
 {
     $doc = new ezcDocumentDocbook();
     $doc->options->indentXml = true;
     $doc->loadFile(dirname(__FILE__) . '/files/xhtml_sample_basic.xml');
     $this->assertEquals(file_get_contents(dirname(__FILE__) . '/files/xhtml_sample_basic_indented.xml'), $doc->save());
 }