Threadsafeの検証をしようとしてこれだけでは上手くいかなかったSpec

params_filter_thread_spec.rb

describe Jpmobile::ParamsFilter do
  include Rack::Test::Methods
  include Jpmobile::RackHelper
  include Jpmobile::Util

 context 'Threadで動作している時' do
    before(:all) do
      @app = Jpmobile::MobileCarrier.new(Jpmobile::ParamsFilter.new(UnitApplication.new))
      @form_params = {
        'bar' => 'baz',
        'hoge' => 'hige',
        'hage' => 'hige',
      }
      @form_string = @form_params.map {|k, v|
        '%s=%s' % [utf8_to_sjis(k), utf8_to_sjis(v)]
      }.join('&')
      @mobile_request = Rack::MockRequest.env_for(
        "/?guid=ON&id=1",
        'REQUEST_METHOD' => 'POST',
        'CONTENT_TYPE' => 'application/x-www-form-urlencoded',
        'HTTP_USER_AGENT' => 'DoCoMo/2.0 SH906i(c100;TB;W24H16)',
        :input => @form_string,
      )
      @not_mobile_request = Rack::MockRequest.env_for(
        "/?guid=ON&id=1",
        'REQUEST_METHOD' => 'GET',
        'CONTENT_TYPE' => 'application/x-www-form-urlencoded',
        'HTTP_USER_AGENT' => 'Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)'
      )
    end

    it '正しいレスポンスが帰る' do
      threads = []
      10.times do
        10.times do
          threads.push(Thread.new{
            sleep 0.5 * rand
            res = @app.call(@mobile_request)
            expect(res[0]).to eq(200)
          })
        end
        100.times do
          threads.push(Thread.new{
            sleep 0.5 * rand
            res = @app.call(@not_mobile_request)
            expect(res[0]).to eq(200)
          })
        end
      end
      threads.each{|t| t.join }
    end
  end
end