create_routes

# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 58
          def create_routes
            app = self.app
            routes = ActionDispatch::Routing::RouteSet.new

            @original_routes ||= app.routes
            @original_routes.singleton_class.redefine_method(:call, &routes.method(:call))

            https = integration_session.https?
            host = integration_session.host

            app.instance_variable_set(:@routes, routes)
            @integration_session = Class.new(ActionDispatch::Integration::Session) do
              include app.routes.url_helpers
              include app.routes.mounted_helpers
            end.new(app)
            @integration_session.https! https
            @integration_session.host! host
            @routes = routes

            yield routes
          end