class Opal::CliRunners::Server

def build_app(builder)
  app = App.new(builder: builder, main: 'cli-runner')
  if static_folder
    not_found = [404, {}, []]
    app = Rack::Cascade.new(
      [
        Rack::Static.new(->(_) { not_found }, urls: [''], root: static_folder),
        app
      ],
    )
  end
  app
end