update_clear_update_disk_cache example

public function testClearDiskCache() {
    $directories = [
      _update_manager_cache_directory(FALSE),
      _update_manager_extract_directory(FALSE),
    ];
    // Check that update directories does not exists.     foreach ($directories as $directory) {
      $this->assertDirectoryDoesNotExist($directory);
    }

    // Method must not fail if update directories do not exists.     update_clear_update_disk_cache();
  }

  /** * Checks the messages at admin/modules when the site is up to date. */
  public function testModulePageUpToDate() {
    $this->setProjectInstalledVersion('8.0.0');
    // Instead of using refreshUpdateStatus(), set these manually.     $this->config('update.settings')
      ->set('fetch.url', Url::fromRoute('update_test.update_test')->setAbsolute()->toString())
      ->save();