# File test/test_multi_process.rb, line 53
    def io_passing_parent
      pin, pout = IO.pipe
      @s1.write('send_io')
      @s1.send_io(pout)
      pout.close
      assert_equal('recv_io', @s1.read(7))
      assert_equal("Hello world.\n", pin.read)
      pin.close

      nil
    end