class DrupalFlushAllCachesInInstallerTest

class DrupalFlushAllCachesInInstallerTest extends BrowserTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    protected $profile = 'cache_flush_test';
    
    /**
     * {@inheritdoc}
     */
    protected function prepareEnvironment() {
        parent::prepareEnvironment();
        $info = [
            'type' => 'profile',
            'core_version_requirement' => '*',
            'name' => 'Cache flush test',
            'install' => [
                'language',
            ],
        ];
        // File API functions are not available yet.
        $path = $this->siteDirectory . '/profiles/cache_flush_test';
        mkdir($path, 0777, TRUE);
        file_put_contents("{$path}/cache_flush_test.info.yml", Yaml::encode($info));
        $php_code = <<<EOF
<?php
function cache_flush_test_install() {
  // Note it is bad practice to call this method during hook_install() as it
  // results in an additional expensive container rebuild.
  drupal_flush_all_caches();
  // Ensure services are available after calling drupal_flush_all_caches().
  \\Drupal::state()->set('cache_flush_test', \\Drupal::hasService('language_negotiator'));
}
EOF;
        file_put_contents("{$path}/cache_flush_test.install", $php_code);
    }
    
    /**
     * Confirms that the installation succeeded.
     */
    public function testInstalled() : void {
        $this->assertTrue(\Drupal::state()->get('cache_flush_test'));
    }

}