php7 display document stored in mongodb 3.4 - php

Question

I am very new to php and mongodb. I have installed php7.0 and mongo 3.4.10 on Ubuntu 16.04.3 LTS.
I can display desired document by entering mongo cli command:
db.testcollection.find({_id:'superid'}).pretty()
It gives me this result:
{ "_id" : "superid", "record" : "whatever" }
But I am tryig to display document from mongodb collection with this php script:
<?php
$mongo = new \MongoDB\Driver\Manager();
$filter = ['_id' => 'superid'];
$options = [];
$query = new \MongoDB\Driver\Query($filter, $options);
$rows = $mongo->executeQuery('db.testcollection', $query);
foreach ($rows as $document) {
print_($document);
var_dump($document);
echo $document;
}
echo "The END"
?>
This only display "The END".
What I am missing in my php script to display mongo query result similarly as cli command?

Answer 1

The problem was:
I have created new databse called test using this commands in mongo shell:
use test;
db.createCollection("testcollection");
db.testcollection.insert({ "_id" : "superid", "record" : "whatever"});
So path to db was test.testcollection not db.testcollection.
When I correct appropriate line like this:
$rows = $mongo->executeQuery('test.testcollection', $query);
It works as expected.
I was confused by mongo shell (cli) that gives me right result without need to specify database name (even after logoff mongo shell and login again).
On the other hand you must specify dbname.collectionname in php (what makes sense) :)