Worker::stack PHP Method

    public function stack(Collectable &$work)
    {
    }

 public function testGetStacked()
 {
     $worker = new Worker();
     $work = new WorkerTestWork();
     $worker->stack($work);
     $this->assertEquals(1, $worker->getStacked());
     $worker->stack($work);
     $this->assertEquals(2, $worker->getStacked());
 }