settings

test-db.php
<?php

include('web/sites/default/settings.php');

$dbHostName = $databases['default']['default']['host'];
$dataBaseName = $databases['default']['default']['database'];
$dbUserName = $databases['default']['default']['username'];
$dbPassword = $databases['default']['default']['password'];
$dbPort = $databases['default']['default']['port'];

$pdo = new PDO('mysql:host='.$dbHostName.';port='.$dbPort.';dbname='.$dataBaseName.'', $dbUserName, $dbPassword, array(
  // PDO::MYSQL_ATTR_SSL_CA    =>'ca.cert',
  PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT => TRUE
  )
);

$query = $pdo->query('SHOW TABLES;');
print_r($query->fetchAll());

return $pdo;