Using capybara_discoball to mount a Rails engine?

[mejackreed]

Hi,

Just wondering if there was any experience with using capybara_discoball to mount a Rails engine (rather than another Rack application eg Sinatra).

I am trying mount a Rails::Engine within Capybara_Discoball in a Rails application and running into dead ends so far.

[jferris]

I haven't tried this, but you should be able to mount any Rack application. We frequently mount fake services written using Sinatra.

What does your boot code currently look like?

[mejackreed]

I was doing something like this:

runner = Capybara::Discoball::Runner.new(WfsRails::Runner)

runner.boot

Then:

require 'wfs_rails'

module WfsRails
  class Runner
    def initialize
      Rails.application.routes.draw do
        mount WfsRails::Engine => '/wfs_rails'
      end
    end
  end

I'm just not really sure what the entry point to a Rails engine should be in something like this.

[jferris]

I think the issue is that Runner needs to be a Rack application, so it should respond to call. It looks like Rails engines are Rack applications themselves; have you tried passing the engine directly? If you want to change the way routing works for the engine or something like that, I think middleware is likely the best approach.

[mejackreed]

Thanks I was able to figure this out with a colleague (thanks @cbeer).

For those interested, you can do something like:

runner = Capybara::Discoball::Runner.new(OpenStruct.new(new: WfsRails::Engine.app))

new for Rails::Engines is a private method and this was just a quick work around to proof of concept the approach.

[cbeer]

Right, the difference being the Rails::Engine API will only hand you an instance of a Rack application, while discoball seems to expect a class.

I wonder if there's some way to adapt discoball to be more lenient about the kinds of things it accepts.