ViewsTestCacheContextFilter.php

<?php

namespace Drupal\views_test_data\Plugin\views\filter;

use Drupal\views\Attribute\ViewsFilter;
use Drupal\views\Plugin\views\filter\FilterPluginBase;
class ViewsTestCacheContextFilter extends FilterPluginBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $this->value = \Drupal::state()->get('views_test_cache_context', 'George');
        parent::query();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheContexts() {
        $cache_contexts = parent::getCacheContexts();
        $cache_contexts[] = 'views_test_cache_context';
        return $cache_contexts;
    }

}