application_helper.rb

  def is_page?(page)
    if params
      params["id"] == page && params["controller"] == "high_voltage/pages"
    else
      false
    end
  end

application_helper_spec.rb

describe ApplicationHelper do
  describe ".is_page?(page)" do
    it "returns true if we're on the page with ID passed as page arg" do
      # need to set our controller params to something like:
      # params = {id: 'a_page', controller:'high_voltage/pages'}
      helper.is_page?('a_page').should == true
    end
  end
end