Typhoeus::Hydra issue

Gemfile

source "http://rubygems.org"

gem 'typhoeus', '>=0.6.2'
#gem 'typhoeus', :git => 'git://github.com/typhoeus/typhoeus.git'
gem 'webmock', '>=1.9.3'
gem 'rspec', :require => 'spec'

spec_helper.rb

# spec/spec_helper.rb

require 'webmock/rspec'
require File.expand_path(File.dirname(__FILE__) + '/../test')

test.rb

require "rubygems"
require "bundler/setup"
require 'typhoeus'

class Foo

  attr_reader :target_url

  def initialize(target_url)
    @target_url = target_url
  end

  def retrieve_files(max_concurrency = 2)
    hydra = Typhoeus::Hydra.new(:max_concurrency => max_concurrency)
    found = []

    urls.each do |url|
      request = Typhoeus::Request.new(url)

      request.on_complete do |response|
        found << response.request.base_url
      end

      hydra.queue(request)
    end

    hydra.run
    found
  end

  def urls
    urls = []

    Foo.files.each {|file| urls << "#@target_url/#{file}"}

    urls
  end

  def self.files
    %w{file1.php file2.php file3.php file4.php}
  end
end

# uncomment this for real case
# foo = Foo.new('http://google.com')
# p foo.retrieve_files

test_spec.rb

# spec/test_spec.rb

require 'spec_helper'

describe Foo do
  let(:url) { 'http://google.com' }
  subject(:foo) { Foo.new(url) }

  before { stub_request(:get, /.*/).to_return(status: 200) }

  describe '#retrieve_files' do
    (1..4).each do |concurrency|

      context "when concurrency = #{concurrency}" do
        it 'returns all the files' do
          foo.retrieve_files(concurrency).sort.should == foo.urls.sort
        end
      end
    end
  end
end