How to test routes in a Rails 3.1 mountable engine This problem has been eluding me for a few weeks... While working on Blogit I wanted to write specs for the routes but kept hitting ActionController::RoutingError with every approach I tried. Finally I discovered this solution: # spec/routing/post_routing_spec.rb ... before do @routes = Blogit::Engine.routes end it "routes /posts/page/:page to posts#index with page param" do { get: "posts/page/2" }.should route_to({ controller: "blogit/posts", action: "index", page: "2" } end Setting the @routes variable to the Blogit Engine's routes seemed to do the trick nicely! There's something really dirty and "hacky" about this approach though - there surely is a better way? If anyone knows, please leave a comment below.