Inheritance: extends Opengraph
 public function testWriter()
 {
     $writer = new Opengraph\Writer();
     $writer->append(Opengraph\Writer::OG_TITLE, 'test');
     $this->assert->string($writer->render())->isEqualTo("\t" . '<meta property="og:title" content="test" />' . PHP_EOL);
     $this->assert->object($writer->addMeta(Opengraph\Writer::OG_TYPE, Opengraph\Writer::TYPE_WEBSITE, Opengraph\Writer::APPEND))->isInstanceOf('\\Opengraph\\Writer');
     $this->assert->object($writer->append(Opengraph\Writer::OG_TYPE, Opengraph\Writer::TYPE_WEBSITE))->isInstanceOf('\\Opengraph\\Writer');
     $this->assert->object($writer->prepend(Opengraph\Writer::OG_IMAGE, 'http://www.google.com/'))->isInstanceOf('\\Opengraph\\Writer');
     $this->assert->object($writer->getMetas())->isInstanceOf('\\ArrayObject');
     $this->assert->string(md5($writer->serialize()))->isEqualTo('34335afeb44c2f54d5e28fa1a499e0b9');
     $this->assert->integer($writer->count())->isEqualTo(3);
     $this->assert->object($writer->current())->isInstanceOf('\\Opengraph\\Meta');
     $this->assert->integer($writer->key())->isEqualTo(0);
     $writer->next();
     $this->assert->integer($writer->key())->isEqualTo(1);
     $this->assert->boolean($writer->valid())->isTrue();
     $writer->next();
     $writer->next();
     $writer->next();
     $this->assert->boolean($writer->valid())->isFalse();
     $writer->rewind();
     $this->assert->integer($writer->key())->isEqualTo(0);
     $writer->unserialize('C:11:"ArrayObject":751:{x:i:0;a:6:{i:0;O:14:"Opengraph\\Meta":2:{s:12:"*_property";s:6:"og:url";s:11:"*_content";s:36:"http://www.imdb.com/title/tt0117500/";}i:1;O:14:"Opengraph\\Meta":2:{s:12:"*_property";s:8:"og:title";s:11:"*_content";s:11:"Rock (1996)";}i:2;O:14:"Opengraph\\Meta":2:{s:12:"*_property";s:7:"og:type";s:11:"*_content";s:11:"video.movie";}i:3;O:14:"Opengraph\\Meta":2:{s:12:"*_property";s:8:"og:image";s:11:"*_content";s:99:"http://ia.media-imdb.com/images/M/MV5BMTM3MTczOTM1OF5BMl5BanBnXkFtZTYwMjc1NDA5._V1._SX98_SY140_.jpg";}i:4;O:14:"Opengraph\\Meta":2:{s:12:"*_property";s:12:"og:site_name";s:11:"*_content";s:4:"IMDb";}i:5;O:14:"Opengraph\\Meta":2:{s:12:"*_property";s:9:"fb:app_id";s:11:"*_content";s:15:"115109575169727";}};m:a:0:{}}');
     $this->assert->integer($writer->count())->isEqualTo(6);
     $this->assert->array($writer->getArrayCopy())->isEqualTo(array('og:url' => 'http://www.imdb.com/title/tt0117500/', 'og:title' => 'Rock (1996)', 'og:type' => 'video.movie', 'og:image' => array(0 => array('og:image:url' => 'http://ia.media-imdb.com/images/M/MV5BMTM3MTczOTM1OF5BMl5BanBnXkFtZTYwMjc1NDA5._V1._SX98_SY140_.jpg')), 'og:site_name' => 'IMDb', 'fb:app_id' => '115109575169727'));
     $this->assert->string($writer->getMeta(Opengraph\Writer::OG_TITLE))->isEqualTo('Rock (1996)');
     /*$this->assert->object($writer->getMeta(Opengraph\Writer::OG_TITLE))
           ->isInstanceOf('\Opengraph\Meta');
       */
     $this->assert->boolean($writer->hasMeta(Opengraph\Writer::OG_TITLE))->isTrue();
     $this->assert->boolean($writer->removeMeta(Opengraph\Writer::OG_TITLE))->isTrue();
     $this->assert->integer($writer->count())->isEqualTo(5);
     $this->assert->boolean($writer->removeMeta(Opengraph\Writer::OG_TITLE))->isFalse();
     $this->assert->boolean($writer->getMeta(Opengraph\Writer::OG_TITLE))->isFalse();
     $this->assert->boolean($writer->hasMeta(Opengraph\Writer::OG_TITLE))->isFalse();
     $writer->addMeta(Opengraph\Writer::OG_TYPE, Opengraph\Writer::TYPE_BOOK, Opengraph\Writer::APPEND);
     $this->assert->string($writer->getMeta(Opengraph\Writer::OG_TYPE))->isEqualTo(Opengraph\Writer::TYPE_BOOK);
     $writer = new Opengraph\Writer();
     $this->assert->integer($writer->count())->isEqualTo(5);
 }
<?php

namespace Application;

require_once __DIR__ . '/../src/Opengraph/Meta.php';
require_once __DIR__ . '/../src/Opengraph/Opengraph.php';
require_once __DIR__ . '/../src/Opengraph/Writer.php';
use Opengraph;
$writer = new Opengraph\Writer();
$writer->append(Opengraph\Writer::OG_TITLE, 'The Rock');
$writer->append(Opengraph\Writer::OG_TYPE, Opengraph\Writer::TYPE_VIDEO_MOVIE);
$writer->append(Opengraph\Writer::OG_URL, 'http://www.imdb.com/title/tt0117500/');
$writer->append(Opengraph\Writer::OG_IMAGE, 'http://ia.media-imdb.com/images/rock.jpg');
echo $writer->render() . PHP_EOL;