class TestHelperPlugin

class TestHelperPlugin extends PluginBase {
    
    /**
     * Stores the defined options.
     *
     * @var array
     */
    protected $definedOptions = [];
    
    /**
     * Calls the protected method setOptionDefaults().
     *
     * @see \Drupal\views\Plugin\views\PluginBase::setOptionDefaults()
     */
    public function testSetOptionDefaults(&$storage, $options, $level = 0) {
        $this->setOptionDefaults($storage, $options);
    }
    
    /**
     * Allows to set the defined options.
     *
     * @param array $options
     *   The options to set.
     *
     * @return $this
     */
    public function setDefinedOptions($options) {
        $this->definedOptions = $options;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        // Normally we provide a limited set of options, but for testing purposes we
        // make it possible to set the defined options statically.
        return $this->definedOptions;
    }

}