rspec with zeus and spork

spec_helper.rb

require 'rubygems'

prefork = lambda {
  ENV["RAILS_ENV"] ||= 'test'
  require File.expand_path("../../config/environment", __FILE__)
  require 'rspec/rails'
}

each_run = lambda {
...
}

if defined?(Zeus)
  prefork.call
  $each_run = each_run
  class << Zeus.plan
    def after_fork_with_test
      after_fork_without_test
      $each_run.call
    end
    alias_method_chain :after_fork, :test
  end

elsif defined?(Spork)
  require 'spork'
  Spork.prefork(&prefork)
  Spork.each_run(&each_run)

else
  prefork.call
  each_run.call
end