Stash\Pool::setDriver PHP Method

    public function setDriver(DriverInterface $driver)
    {
        $this->driver = $driver;
    }

 protected function setUp()
 {
     $this->driver = new Ephemeral([]);
     $this->pool = new Pool();
     $this->pool->setDriver($this->driver);
     $this->pool->setItemClass('Bankiru\\Stash\\TaggedItem');
 }