specify posix.fcntl:

- before:

    fc = require "posix.fcntl"

- describe open:

  - before: |

      unistd = require "posix.unistd"

      O_CREAT, O_RDONLY, O_WRONLY = fc.O_CREAT, fc.O_RDONLY, fc.O_WRONLY

      open = fc.open

      close, read, write = unistd.close, unistd.read, unistd.write

      dir = posix.mkdtemp (template)

      fh = io.open (dir .. "/file", "w")

      fh:write "garbage\n"

      fh:close ()

  - after:

      rmtmp (dir)

  - context with bad arguments:

      badargs.diagnose (open, "(string, int, ?int)")

  - it opens an existing file:

      fd, err = open (dir .. "/file", O_RDONLY)

      expect (type (fd)).to_be "number"

      expect (fd >= 0).to_be (true)

      expect (read (fd, 10)).to_be "garbage\n"

      close (fd)

  - it opens a new file:

      buf = "more garbage\n"

      fd, err = open (dir .. "/creat", bor (O_CREAT, O_WRONLY))

      expect (type (fd)).to_be "number"

      expect (fd >= 0).to_be (true)

      expect (write (fd, buf)).to_be (#buf)

      close (fd)

- describe posix_fadvise:

  - before:

      posix_fadvise = fc.posix_fadvise

  - context with bad arguments:

      if posix_fadvise then

        badargs.diagnose (posix_fadvise, "(int, int, int, int)")

      end