/**
  * Tests installation and uninstallation.
  */
 function testInstallationAndUninstallation()
 {
     /** @var \Drupal\Core\Extension\ModuleInstallerInterface $module_installer */
     $module_installer = \Drupal::service('module_installer');
     $module_handler = \Drupal::moduleHandler();
     $this->assertTrue(Currency::load('XXX') instanceof CurrencyInterface);
     $this->assertTrue(CurrencyLocale::load('en_US') instanceof CurrencyLocaleInterface);
     $module_installer->uninstall(array('currency'));
     $this->assertFalse($module_handler->moduleExists('currency'));
 }