should_be_mocked.rb

if Rails.env.test?
  class TCPSocket
    alias_method :old_initialize, :initialize
    def initialize(*args)
      if !['localhost', '127.0.0.1', 'www.example.com'].include?(args.first)
        # Uncomment and comment the raise line to log all the violations
        # logger = Logger.new(File.join(Rails.root, 'log', 'open_sockets.log'))
        # logger.info "#{Time.now}: #{args.inspect}"
        raise "#{Time.now}: #{args.inspect}"
      end
      old_initialize(*args)
    end
  end
end