Lib/test/test_pty.py

   1 import pty, os, sys
   2 from test.test_support import verbose, TestFailed, TestSkipped
   3
   4 TEST_STRING_1 = "I wish to buy a fish license.\n"
   5 TEST_STRING_2 = "For my pet fish, Eric.\n"
   6
   7 if verbose:
   8     def debug(msg):
   9         print msg
  10 else:
  11     def debug(msg):
  12         pass
  13
  14 # Marginal testing of pty suite. Cannot do extensive 'do or fail' testing
  15 # because pty code is not too portable.
  16
  17 try:
  18     debug("Calling master_open()")
  19     master_fd, slave_name = pty.master_open()
  20     debug("Got master_fd '%d', slave_name '%s'"%(master_fd, slave_name))
  21     debug("Calling slave_open(%s)"%`slave_name`)
  22     slave_fd = pty.slave_open(slave_name)
  23     debug("Got slave_fd '%d'"%slave_fd)
  24 except OSError:
  25     # " An optional feature could not be imported " ... ?
  26     raise TestSkipped, "Pseudo-terminals (seemingly) not functional."
  27
  28 if not os.isatty(slave_fd):
  29     raise TestFailed, "slave_fd is not a tty"
  30
  31 # IRIX apparently turns \n into \r\n. Allow that, but avoid allowing other
  32 # differences (like extra whitespace, trailing garbage, etc.)
  33
  34 debug("Writing to slave_fd")
  35 os.write(slave_fd, TEST_STRING_1)
  36 s1 = os.read(master_fd, 1024)
  37 sys.stdout.write(s1.replace("\r\n", "\n"))
  38
  39 debug("Writing chunked output")
  40 os.write(slave_fd, TEST_STRING_2[:5])
  41 os.write(slave_fd, TEST_STRING_2[5:])
  42 s2 = os.read(master_fd, 1024)
  43 sys.stdout.write(s2.replace("\r\n", "\n"))
  44
  45 os.close(slave_fd)
  46 os.close(master_fd)
  47
  48 # basic pty passed.
  49
  50 debug("calling pty.fork()")
  51 pid, master_fd = pty.fork()
  52 if pid == pty.CHILD:
  53     # stdout should be connected to a tty.
  54     if not os.isatty(1):
  55         debug("Child's fd 1 is not a tty?!")
  56         os._exit(3)
  57
  58     # After pty.fork(), the child should already be a session leader.
  59     # (on those systems that have that concept.)
  60     debug("In child, calling os.setsid()")
  61     try:
  62         os.setsid()
  63     except OSError:
  64         # Good, we already were session leader
  65         debug("Good: OSError was raised.")
  66         pass
  67     except AttributeError:
  68         # Have pty, but not setsid() ?
  69         debug("No setsid() available ?")
  70         pass
  71     except:
  72         # We don't want this error to propagate, escaping the call to
  73         # os._exit() and causing very peculiar behavior in the calling
  74         # regrtest.py !
  75         # Note: could add traceback printing here.
  76         debug("An unexpected error was raised.")
  77         os._exit(1)
  78     else:
  79         debug("os.setsid() succeeded! (bad!)")
  80         os._exit(2)
  81     os._exit(4)
  82 else:
  83     debug("Waiting for child (%d) to finish."%pid)
  84     (pid, status) = os.waitpid(pid, 0)
  85     res = status >> 8
  86     debug("Child (%d) exited with status %d (%d)."%(pid, res, status))
  87     if res == 1:
  88         raise TestFailed, "Child raised an unexpected exception in os.setsid()"
  89     elif res == 2:
  90         raise TestFailed, "pty.fork() failed to make child a session leader."
  91     elif res == 3:
  92         raise TestFailed, "Child spawned by pty.fork() did not have a tty as stdout"
  93     elif res != 4:
  94         raise TestFailed, "pty.fork() failed for unknown reasons."
  95
  96 os.close(master_fd)
  97
  98 # pty.fork() passed.