Testing rails mountable engine routes with rspec • Coding Stuff

In order to test engine routes (and controllers) you may need to set the routes attributes:

describe Gossiper::NotificationsController, 'routing' do
   # here's the trick
   routes { Gossiper::Engine.routes }

  it "routes to index" do
    expect(get('/notifications')).to
      route_to('gossiper/notifications#index')
  end
end