RefreshVariablesTrait.php

<?php

namespace Drupal\Core\Test;

use Drupal\Core\Cache\Cache;

/**
 * Provides a method to refresh in-memory configuration and state information.
 */
trait RefreshVariablesTrait {
    
    /**
     * Refreshes in-memory configuration and state information.
     *
     * Useful after a page request is made that changes configuration or state in
     * a different thread.
     *
     * In other words calling a settings page with $this->drupalPostForm() with a
     * changed value would update configuration to reflect that change, but in the
     * thread that made the call (thread running the test) the changed values
     * would not be picked up.
     *
     * This method clears the cache and loads a fresh copy.
     */
    protected function refreshVariables() {
        // Clear the tag cache.
        \Drupal::service('cache_tags.invalidator')->resetChecksums();
        foreach (Cache::getBins() as $backend) {
            if (is_callable([
                $backend,
                'reset',
            ])) {
                $backend->reset();
            }
        }
        \Drupal::service('config.factory')->reset();
        \Drupal::service('state')->resetCache();
    }

}