This is the most succinct style I can come up with for writing routing specs.

1_routing_spec.rb

require 'component/component_spec_helper'

describe "Routing", type: :routing do
  describe "for the home page" do
    specify {{ get: '/' }.should route_to('lists#index') }
  end
  describe "for authentication" do
    specify {{ get: '/auth/new' }.should route_to('sessions#new') }
    specify {{ get: '/auth/37signals/callback' }.should route_to('sessions#create', provider: '37signals') }
    specify {{ get: '/auth/failure' }.should route_to('sessions#failure') }
  end
  describe "for lists" do
    specify {{ get: '/lists' }.should route_to('lists#index') }
    specify {{ get: '/lists/new' }.should route_to('lists#new') }
    specify {{ post: '/lists' }.should route_to('lists#create') }
    specify {{ get: '/lists/3/edit' }.should route_to('lists#edit', id: '3') }
    specify {{ put: '/lists/3' }.should route_to('lists#update', id: '3') }
    specify {{ delete: '/lists/3' }.should route_to('lists#destroy', id: '3') }
  end
  describe "for basecamp" do
    specify {{ post: '/basecamp/projects/1/lists' }.should route_to('basecamp#create_list', project_id: '1') }
  end
end

2_output.txt

Routing
  for the home page
    should route {:get=>"/"} to {:controller=>"lists", :action=>"index"}
  for authentication
    should route {:get=>"/auth/new"} to {:controller=>"sessions", :action=>"new"}
    should route {:get=>"/auth/37signals/callback"} to {:provider=>"37signals", :controller=>"sessions", :action=>"create"}
    should route {:get=>"/auth/failure"} to {:controller=>"sessions", :action=>"failure"}
  for lists
    should route {:get=>"/lists"} to {:controller=>"lists", :action=>"index"}
    should route {:get=>"/lists/new"} to {:controller=>"lists", :action=>"new"}
    should route {:post=>"/lists"} to {:controller=>"lists", :action=>"create"}
    should route {:get=>"/lists/3/edit"} to {:id=>"3", :controller=>"lists", :action=>"edit"}
    should route {:put=>"/lists/3"} to {:id=>"3", :controller=>"lists", :action=>"update"}
    should route {:delete=>"/lists/3"} to {:id=>"3", :controller=>"lists", :action=>"destroy"}
  for basecamp
    should route {:post=>"/basecamp/projects/1/lists"} to {:project_id=>"1", :controller=>"basecamp", :action=>"create_list"}