test_server.rb

#!/usr/bin/ruby

require 'gems/environment'
require 'rack'
require 'thin'
require 'em-http'

module Rack
  module TestServer
    def self.run app, middlewares=[], &block
      app = app.kind_of?(Class) ? Class.new(app) : app
      EM.run {
        server = Thread.new do
          Thin::Logging.silent = true
          Thin::Server.start('127.0.0.1', 12345) do
            middlewares.each {|m| use m }
            use Rack::TestServer::Logger
            run app
          end
        end
        sleep 0.1
        client = Thread.new { block.call(app) }
        server.join
        client.join
      }
    end

    def self.logs
      @@logs ||= []
    end

    class Logger
      def initialize app
        @app = app
      end
      def call env
        res = @app.call env
        TestServer.logs << [ env, res ]
        res
      end
    end
  end
end

Rack::TestServer.run lambda {|env| [ 200, {}, 'ok' ]} do |app|
  http = EventMachine::HttpRequest.new('http://127.0.0.1:12345/').get
  http.callback { p http.response; EM.stop }
  http.errback  { puts "failed"; EM.stop }
end