public function testGetIdList()
{
// create new document
$document1Id = $this->collection->createDocument(array('p' => 1))->save()->getId();
// create new document
$document2Id = $this->collection->createDocument(array('p' => 1))->save()->getId();
$this->assertEquals(array($document1Id, $document2Id), $this->collection->find()->sort(array('p' => 1))->getIdList());
}