public function restore($version) {
    $fixture = "tests/fixtures/$version.sql";

    if (file_exists("$fixture.bz2")) {
      return $this->collectionBuilder()
        ->addTask(
          $this->taskExec('bunzip2')->arg("$fixture.bz2")->option('keep')->option('force')
        )
        ->addTask(
          $this->taskDrupal('database:restore')->option('file', "../$fixture")
        )
        ->completion(
          $this->taskFilesystemStack()->remove($fixture)
        );
    }
    else {
      $this->say("$version fixture does not exist.");
    }
  }