public function testIsset()
{
$doc = new Document(array('data' => array('title' => 'Post', 'content' => 'Lorem Ipsum', 'extra' => array('foo' => 'bar'))));
$this->assertTrue(isset($doc->title));
$this->assertTrue(isset($doc->content));
$this->assertFalse(isset($doc->body));
$key = 'extra.foo';
$this->assertTrue(isset($doc->{$key}));
$key = 'extra.baz';
$this->assertFalse(isset($doc->{$key}));
}