$this->drupalGet('/upgrade'); $session->pageTextContains("An upgrade has already been performed on this site. To perform a new migration, create a clean and empty new install of Drupal $this->destinationSiteVersion. Rollbacks are not yet supported through the user interface."); $this->submitForm([], 'Import new configuration and content from old site'); $this->submitForm($this->edits, 'Review upgrade'); $this->submitForm([], 'I acknowledge I may lose data. Continue anyway.');