Saving and restoring Capybara sessions

capybara_session_factory.rb

module CapybaraSessionFactory

  class SessionAlreadyDefined < StandardError; end
  class SessionNotDefined < StandardError; end

  # Parse a capybara session mode, which has the form
  # "[driver]:[session_name]:[application_id]"
  #
  class CapybaraModeParser

    attr_reader :driver, :session_name, :application_id

    def initialize(mode)
      @mode = mode
      parse
    end

    private

      def parse
        @driver, @session_name, @application_id = @mode.split(':')
      end

  end

  class Session

    include Capybara::DSL

    def initialize(name, setup_proc)
      @name, @setup_proc = name, setup_proc
      @is_setup = false
    end

    def setup?
      @is_setup
    end

    def run_setup
      return if setup?
      instance_eval(&@setup_proc)
      @is_setup = true
    end

    def capybara_session_name
      "capybara_session_factory_#{@name}"
    end

  end

  class << self

    # Defines a new session and its setup code.
    #
    def define_session(name, &setup_proc)
      raise SessionAlreadyDefined if sessions.key?(name)
      sessions[name] = Session.new(name, setup_proc)
    end

    # Loads a session by name.
    # The setup code is only run on the first load.
    #
    def load_session(name)
      raise SessionNotDefined unless sessions.key?(name)

      session = sessions[name]

      Capybara.using_session(name) do
        session.run_setup unless session.setup?
        yield
      end
    end

    private

      def sessions
        @sessions ||= {}
      end

      # Returns true if the capybara mode string corresponds to a
      # CapybaraSessionFactory session.
      #
      def managed_session_mode?(mode)
        parser = CapybaraModeParser.new(mode)
        sessions.key?(parser.session_name)
      end

  end

end

class << Capybara

  # Force capybara not to reset sessions that are managed by CapybaraSessionFactory.
  # This let's sessions persist between tests.
  #
  # TODO: Capybara doesn't allow management of its "session_pool", so we need to monkey-path.
  # Capybara should be updated with a session manager strategy so this is not required.
  #
  def reset_sessions!
    session_pool.each do |mode, session|
      session.reset! unless CapybaraSessionFactory.managed_session_mode?(mode)
    end
  end
  alias_method :reset!, :reset_sessions!

end

dashboard_spec.rb

# spec/features/dashboard_spec.rb

require 'spec_helper'

describe 'the dashboard' do
  
  it 'has a welcome message' do
    CapybaraSessionFactory.load_session('signed in') do
      click_link 'Dashboard'
      
      expect(page).to have_content 'Welcome to your dashboard'
    end
  end
  
end

signed_in.rb

# spec/sessions/signed_in.rb

CapybaraSessionFactory.define_session 'signed in' do
  visit '/signup'
  fill_in 'First name', with: 'Bob'
  fill_in 'Email', with: 'bob@gmail.com'
  fill_in 'Password', with: 'password'
  click_button 'Sign Up'
end