class RowTest

class RowTest extends RowPluginBase {
    
    /**
     * A string which will be output when the view is rendered.
     *
     * @var string
     */
    public $output;
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['test_option'] = [
            'default' => '',
        ];
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        parent::buildOptionsForm($form, $form_state);
        $form['test_option'] = [
            '#title' => $this->t('Test option'),
            '#type' => 'textfield',
            '#description' => $this->t('This is a textfield for test_option.'),
            '#default_value' => $this->options['test_option'],
        ];
    }
    
    /**
     * Sets the output property.
     *
     * @param string $output
     *   The string to output by this plugin.
     */
    public function setOutput($output) {
        $this->output = $output;
    }
    
    /**
     * Returns the output property.
     *
     * @return string
     */
    public function getOutput() {
        return $this->output;
    }
    
    /**
     * {@inheritdoc}
     */
    public function render($row) {
        return $this->getOutput();
    }
    
    /**
     * {@inheritdoc}
     */
    public function calculateDependencies() {
        return [
            'content' => [
                'RowTest',
            ],
        ];
    }

}