How to test with RSpec a Rails plugin using “link_to” and “current_page?”

I'm writing a Rails plugin that builds up a menu in a view. I'm using
*link`_`to* to build the link and *current_page?* to set
class="active" on the current page.

I've *include*d *ActionView::Helpers::UrlHelper* so I can use
*link`_`to*.

To get *current`_`page?* working in the view, I've had to inherit the
current class (apparently ActionView::Base) and it works perfectly
well. Unfortunately, this totally breaks the tests with RSpec.

I'm calling *link`_`to* and *current`_`page?* like this:

    def menu(options = {}, &block)
      carte = my_menu.new(self)
      yield carte
      carte.to_s unless carte.empty?
    end

    class my_menu
      include ActionView::Helpers::TagHelper
      include ActionView::Helpers::UrlHelper

      def initialize(base)
        @base = base
      end

      def link
        @base.link_to(name, url_options, html_options)
        @base.current_page?(url_options)
      end
    end

And I get this error with RSpec:
    Undefined method `link_to' for #<
Spec::Rails::Example::RailsExampleGroup::Subclass_1:0x24afa90>

Any clue?