public function testMetaData()
{
$this->mapping->setMetaData(['author' => 'Nil Portugués']);
$this->mapping->addMetaData('created_in', '0.00001232 seconds');
$this->assertEquals(['author' => 'Nil Portugués', 'created_in' => '0.00001232 seconds'], $this->mapping->getMetaData());
}