class TestAccessBlock

class TestAccessBlock extends BlockBase implements ContainerFactoryPluginInterface {
  
  /**
   * The state service.
   */
  protected $state;
  
  /**
   * Tests the test access block.
   *
   *
   * @param array $configuration
   *   The plugin configuration, i.e. an array with configuration values keyed
   *   by configuration option name. The special key 'context' may be used to
   *   initialize the defined contexts by setting it to an array of context
   *   values keyed by context names.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\Core\State\StateInterface $state
   *   The state.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, StateInterface $state) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->state = $state;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($configuration, $plugin_id, $plugin_definition, $container->get('state'));
  }
  
  /**
   * {@inheritdoc}
   */
  protected function blockAccess(AccountInterface $account) {
    return $this->state
      ->get('test_block_access', FALSE) ? AccessResult::allowed()->setCacheMaxAge(0) : AccessResult::forbidden()->setCacheMaxAge(0);
  }
  
  /**
   * {@inheritdoc}
   */
  public function build() {
    return [
      '#markup' => 'Hello test world',
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCacheMaxAge() {
    return Cache::PERMANENT;
  }

}