specify posix.sys.msg:
- before:
    errno = require "posix.errno"
    msg   = require "posix.sys.msg"
    st    = require "posix.sys.stat"

    EEXIST = errno.EEXIST
    msgget, msgsnd, msgrcv = msg.msgget, msg.msgsnd, msg.msgrcv
    IPC_CREAT, IPC_EXCL = msg.IPC_CREAT, msg.IPC_EXCL
    S_IRWXU, S_IRWXG, S_IRWXO = st.S_IRWXU, st.S_IRWXG, st.S_IRWXO

    mode = bor (S_IRWXU, S_IRWXG, S_IRWXO)
    mq, err, errnum = msgget (100, bor (IPC_CREAT, IPC_EXCL, mode))
    if errnum == EEXIST then
      mq, err = msgget (100, mode)
    end

    type = 42
    data = "Answer to the Ultimate Question of Life"


- describe msgget:
  - context with bad arguments:
      badargs.diagnose (msgget, "(int, ?int)")

  - it creates a queue:
      expect (mq).not_to_be (nil)
      expect (err).to_be (nil)


- describe msgsnd:
  - context with bad arguments:
      badargs.diagnose (msgsnd, "(int, int, string, ?int)")

  - it sends a message:
      ok, err = msgsnd (mq, type, data)
      expect (ok).not_to_be (err)


- describe msgrcv:
  - context with bad arguments:
      badargs.diagnose (msgrcv, "(int, int, ?int, ?int)")

  - it receives a message:
      expect ({msgrcv (mq, 128)}).to_equal {type, data, nil}