create_routes

# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 270
        def create_routes(config = nil)
          @routes = ActionDispatch::Routing::RouteSet.new(config || ActionDispatch::Routing::RouteSet::DEFAULT_CONFIG)
          if @controller
            @controller = @controller.clone
            _routes = @routes

            @controller.singleton_class.include(_routes.url_helpers)

            if @controller.respond_to? :view_context_class
              view_context_class = Class.new(@controller.view_context_class) do
                include _routes.url_helpers
              end

              custom_view_context = Module.new {
                define_method(:view_context_class) do
                  view_context_class
                end
              }
              @controller.extend(custom_view_context)
            end
          end
          yield @routes
        end