Tests the System queue.
public function testSystemQueue() {
$this
->installSchema('system', 'queue');
// Create two queues.
$queue1 = new DatabaseQueue($this
->randomName(), Database::getConnection());
$queue1
->createQueue();
$queue2 = new DatabaseQueue($this
->randomName(), Database::getConnection());
$queue2
->createQueue();
$this
->queueTest($queue1, $queue2);
}