  $ dune exec ./trivial.exe
  Ok

  $ dune exec ./start.exe
  Ok

  $ dune exec ./stop.exe
  Ok

  $ dune exec ./oneshot.exe
  Signal
  Ok

  $ dune exec ./signum.exe
  true

  $ dune exec ./start_exception.exe
  Ok

  $ dune exec ./oneshot_exception.exe
  Ok
