public function testItem()
{
$item = new Item();
$date = new DateTime();
$item->setId('id');
$item->setName('name');
$item->setIntro('intro');
$item->setContent('content');
$item->setSource('source');
$item->setAuthor('author');
$item->setImage('image');
$item->setDate($date);
$item->setExtra('key', 'value');
$item->setTags(array('tag'));
$this->assertEquals('id', $item->getId());
$this->assertEquals('name', $item->getName());
$this->assertEquals('intro', $item->getIntro());
$this->assertEquals('content', $item->getContent());
$this->assertEquals('source', $item->getSource());
$this->assertEquals('author', $item->getAuthor());
$this->assertEquals('image', $item->getImage());
$this->assertEquals($date, $item->getDate());
$this->assertEquals('value', $item->getExtra('key'));
$this->assertEquals(null, $item->getExtra('key-no-exist'));
$this->assertEquals(array('tag'), $item->getTags());
}