def undo_bundler
      clean_env = nil
      Bundler.with_clean_env do
        clean_env = ENV.to_hash
      end
      ENV.replace(clean_env)
    end
def undo_bundler
      clean_env = nil
      Bundler.with_clean_env do
        clean_env = ENV.to_hash
      end
      ENV.replace(clean_env)
    end
Unit tests must undo the Bundler environment so that the gem's
 own Gemfile doesn't affect subprocesses that may have their
 own Gemfile.