MockUserNameBlock.php

<?php

namespace Drupal\plugin_test\Plugin\plugin_test\mock_block;

use Drupal\Core\Plugin\ContextAwarePluginInterface;
use Drupal\Core\Plugin\ContextAwarePluginTrait;
use Drupal\Core\Plugin\PluginBase;

/**
 * Implementation of a user name block plugin used by Plugin API context test.
 *
 * @see \Drupal\plugin_test\Plugin\MockBlockManager
 */
class MockUserNameBlock extends PluginBase implements ContextAwarePluginInterface {
    use ContextAwarePluginTrait;
    public function getTitle() {
        $user = $this->getContextValue('user');
        return $user->label();
    }

}