/Lib/test/test_poll.py

  1# Test case for the os.poll() function
  2
  3import os, select, random, unittest
  4from test.test_support import TestSkipped, TESTFN, run_unittest
  5
  6try:
  7    select.poll
  8except AttributeError:
  9    raise TestSkipped, "select.poll not defined -- skipping test_poll"
 10
 11
 12def find_ready_matching(ready, flag):
 13    match = []
 14    for fd, mode in ready:
 15        if mode & flag:
 16            match.append(fd)
 17    return match
 18
 19class PollTests(unittest.TestCase):
 20
 21    def test_poll1(self):
 22        # Basic functional test of poll object
 23        # Create a bunch of pipe and test that poll works with them.
 24
 25        p = select.poll()
 26
 27        NUM_PIPES = 12
 28        MSG = " This is a test."
 29        MSG_LEN = len(MSG)
 30        readers = []
 31        writers = []
 32        r2w = {}
 33        w2r = {}
 34
 35        for i in range(NUM_PIPES):
 36            rd, wr = os.pipe()
 37            p.register(rd)
 38            p.modify(rd, select.POLLIN)
 39            p.register(wr, select.POLLOUT)
 40            readers.append(rd)
 41            writers.append(wr)
 42            r2w[rd] = wr
 43            w2r[wr] = rd
 44
 45        bufs = []
 46
 47        while writers:
 48            ready = p.poll()
 49            ready_writers = find_ready_matching(ready, select.POLLOUT)
 50            if not ready_writers:
 51                raise RuntimeError, "no pipes ready for writing"
 52            wr = random.choice(ready_writers)
 53            os.write(wr, MSG)
 54
 55            ready = p.poll()
 56            ready_readers = find_ready_matching(ready, select.POLLIN)
 57            if not ready_readers:
 58                raise RuntimeError, "no pipes ready for reading"
 59            rd = random.choice(ready_readers)
 60            buf = os.read(rd, MSG_LEN)
 61            self.assertEqual(len(buf), MSG_LEN)
 62            bufs.append(buf)
 63            os.close(r2w[rd]) ; os.close( rd )
 64            p.unregister( r2w[rd] )
 65            p.unregister( rd )
 66            writers.remove(r2w[rd])
 67
 68        self.assertEqual(bufs, [MSG] * NUM_PIPES)
 69
 70    def poll_unit_tests(self):
 71        # returns NVAL for invalid file descriptor
 72        FD = 42
 73        try:
 74            os.close(FD)
 75        except OSError:
 76            pass
 77        p = select.poll()
 78        p.register(FD)
 79        r = p.poll()
 80        self.assertEqual(r[0], (FD, select.POLLNVAL))
 81
 82        f = open(TESTFN, 'w')
 83        fd = f.fileno()
 84        p = select.poll()
 85        p.register(f)
 86        r = p.poll()
 87        self.assertEqual(r[0][0], fd)
 88        f.close()
 89        r = p.poll()
 90        self.assertEqual(r[0], (fd, select.POLLNVAL))
 91        os.unlink(TESTFN)
 92
 93        # type error for invalid arguments
 94        p = select.poll()
 95        self.assertRaises(TypeError, p.register, p)
 96        self.assertRaises(TypeError, p.unregister, p)
 97
 98        # can't unregister non-existent object
 99        p = select.poll()
100        self.assertRaises(KeyError, p.unregister, 3)
101
102        # Test error cases
103        pollster = select.poll()
104        class Nope:
105            pass
106
107        class Almost:
108            def fileno(self):
109                return 'fileno'
110
111        self.assertRaises(TypeError, pollster.register, Nope(), 0)
112        self.assertRaises(TypeError, pollster.register, Almost(), 0)
113
114    # Another test case for poll().  This is copied from the test case for
115    # select(), modified to use poll() instead.
116
117    def test_poll2(self):
118        cmd = 'for i in 0 1 2 3 4 5 6 7 8 9; do echo testing...; sleep 1; done'
119        p = os.popen(cmd, 'r')
120        pollster = select.poll()
121        pollster.register( p, select.POLLIN )
122        for tout in (0, 1000, 2000, 4000, 8000, 16000) + (-1,)*10:
123            fdlist = pollster.poll(tout)
124            if (fdlist == []):
125                continue
126            fd, flags = fdlist[0]
127            if flags & select.POLLHUP:
128                line = p.readline()
129                if line != "":
130                    self.fail('error: pipe seems to be closed, but still returns data')
131                continue
132
133            elif flags & select.POLLIN:
134                line = p.readline()
135                if not line:
136                    break
137                continue
138            else:
139                self.fail('Unexpected return value from select.poll: %s' % fdlist)
140        p.close()
141
142    def test_poll3(self):
143        # test int overflow
144        pollster = select.poll()
145        pollster.register(1)
146
147        self.assertRaises(OverflowError, pollster.poll, 1L << 64)
148
149        x = 2 + 3
150        if x != 5:
151            self.fail('Overflow must have occurred')
152
153def test_main():
154    run_unittest(PollTests)
155
156if __name__ == '__main__':
157    test_main()