Lib/test/test_signal.py

   1 # Test the signal module
   2 from test.test_support import verbose, TestSkipped, TestFailed
   3 import signal
   4 import os, sys, time
   5
   6 if sys.platform[:3] in ('win', 'os2') or sys.platform=='riscos':
   7     raise TestSkipped, "Can't test signal on %s" % sys.platform
   8
   9 if verbose:
  10     x = '-x'
  11 else:
  12     x = '+x'
  13 pid = os.getpid()
  14
  15 # Shell script that will send us asynchronous signals
  16 script = """
  17  (
  18         set %(x)s
  19         sleep 2
  20         kill -HUP %(pid)d
  21         sleep 2
  22         kill -USR1 %(pid)d
  23         sleep 2
  24         kill -USR2 %(pid)d
  25  ) &
  26 """ % vars()
  27
  28 def handlerA(*args):
  29     if verbose:
  30         print "handlerA", args
  31
  32 class HandlerBCalled(Exception):
  33     pass
  34
  35 def handlerB(*args):
  36     if verbose:
  37         print "handlerB", args
  38     raise HandlerBCalled, args
  39
  40 signal.alarm(20)                        # Entire test lasts at most 20 sec.
  41 hup = signal.signal(signal.SIGHUP, handlerA)
  42 usr1 = signal.signal(signal.SIGUSR1, handlerB)
  43 usr2 = signal.signal(signal.SIGUSR2, signal.SIG_IGN)
  44 alrm = signal.signal(signal.SIGALRM, signal.default_int_handler)
  45
  46 try:
  47     os.system(script)
  48
  49     print "starting pause() loop..."
  50
  51     try:
  52         while 1:
  53             if verbose:
  54                 print "call pause()..."
  55             try:
  56                 signal.pause()
  57                 if verbose:
  58                     print "pause() returned"
  59             except HandlerBCalled:
  60                 if verbose:
  61                     print "HandlerBCalled exception caught"
  62                 else:
  63                     pass
  64
  65     except KeyboardInterrupt:
  66         if verbose:
  67             print "KeyboardInterrupt (assume the alarm() went off)"
  68
  69 finally:
  70     signal.signal(signal.SIGHUP, hup)
  71     signal.signal(signal.SIGUSR1, usr1)
  72     signal.signal(signal.SIGUSR2, usr2)
  73     signal.signal(signal.SIGALRM, alrm)