Move Clubs application invitation responsibilities to a controller

invitations_controller.rb

# app/controllers/admin/clubs/applications/invitations_controller.rb
module Admin
  module Clubs
    module Applications
      # InvitationsController allows an application invitation to be sent, and
      # to trigger subsequent actions, such as setting state on the application
      # or sending an invitation email.
      class InvitationsController < Admin::ApplicationController
        respond_to :js
        before_filter :set_application

        def create
          @invitation = @application.invitations.create!
          @application.invite
          @application.schedulable

          ClubsMailer.next_steps_application(
            @application.applicant.user.id
          ).deliver
        end

        private

        def set_application
          @application = ::Clubs::Application.find(params[:application_id])
        end
      end
    end
  end
end

invitations_controller_spec.rb

# spec/controllers/admin/clubs/applications/invitations_controller_spec.rb
require 'spec_helper'

describe Admin::Clubs::Applications::InvitationsController do
  let(:admin_user) { create(:user, :admin) }
  let(:application) { create(:clubs_application) }

  context 'when signed in' do
    before { sign_in(admin_user) }

    # POST :create
    describe 'POST #create' do
      it 'assigns the given application to @application' do
        post :create, application_id: application.id
        expect(assigns(:application)).to eq(application)
      end

      it 'creates an invitation notification' do
        expect {
          post :create, application_id: application.id
        }.to change(Clubs::Notification::Invitation, :count).by(1)
      end

      it 'sets the application state to schedulable' do
        post :create, application_id: application.id
        application.reload
        expect(application.schedulable?).to eq(true)
      end

      it 'sets the invited_at timestamp' do
        Timecop.freeze do
          post :create, application_id: application.id
          application.reload
          expect(application.invited_at.to_i).to eq(Time.now.to_i)
        end
      end

      it 'renders the invite template' do
        post :create, application_id: application.id
        expect(response).to render_template(:create)
      end
    end
  end
end

routes.rb

# config/routes.rb
namespace :clubs do
  resources :applications do
    scope module: 'applications' do
      resource :invitation, only: [:create]
    end
  end
end