# File test/test_multi_process.rb, line 134
    def test_cancel
      pin, pout = IO.pipe
      pid = fork{
        pout.close
        pin.read(1)
        pin.close
        @restart_signal.notify_restart # call on child process
        exit!
      }
      pin.close

      begin
        th = Thread.new{
          @restart_signal.wait # call on parent process
        }
        @restart_signal.cancel # call on parent process
        pout.write("\0")
        pout.close
      ensure
        th.join
      end
      Process.waitpid(pid, 0)
      assert_equal(0, @restart_call)
      assert_equal(0, @close_call)
    end