class TestSessionBag

class TestSessionBag implements SessionBagInterface {
    
    /**
     * The bag name.
     */
    const BAG_NAME = 'session_test';
    
    /**
     * Key used when persisting the session.
     *
     * @var string
     */
    protected $storageKey;
    
    /**
     * Storage for data to save.
     *
     * @var array
     */
    protected $attributes = [];
    
    /**
     * Constructs a new TestSessionBag object.
     *
     * @param string $storage_key
     *   The key used to store test attributes.
     */
    public function __construct($storage_key = '_dp_session_test') {
        $this->storageKey = $storage_key;
    }
    
    /**
     * Sets the test flag.
     */
    public function setFlag() {
        $this->attributes['test_flag'] = TRUE;
    }
    
    /**
     * Returns TRUE if the test flag is set.
     *
     * @return bool
     *   TRUE when flag is set, FALSE otherwise.
     */
    public function hasFlag() {
        return !empty($this->attributes['test_flag']);
    }
    
    /**
     * Clears the test flag.
     */
    public function clearFlag() {
        unset($this->attributes['test_flag']);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getName() : string {
        return self::BAG_NAME;
    }
    
    /**
     * {@inheritdoc}
     */
    public function initialize(array &$attributes) {
        $this->attributes =& $attributes;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getStorageKey() : string {
        return $this->storageKey;
    }
    
    /**
     * {@inheritdoc}
     */
    public function clear() : mixed {
        $return = $this->attributes;
        $this->attributes = [];
        return $return;
    }

}