assertTrue(\Drupal::hasService('service_provider_test_class'), 'The service_provider_test_class service has been registered to the DIC'); // The event subscriber method in the test class calls drupal_set_message() // with a message saying it has fired. This will fire on every page request // so it should show up on the front page. $this->drupalGet(''); $this->assertText(t('The service_provider_test event subscriber fired!'), 'The service_provider_test event subscriber fired'); } }