583 lines
16 KiB
Python
583 lines
16 KiB
Python
"""
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Various tests for synchronization primitives.
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"""
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import sys
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import time
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from thread import start_new_thread, get_ident
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import threading
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import unittest
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from test import test_support as support
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def _wait():
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# A crude wait/yield function not relying on synchronization primitives.
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time.sleep(0.01)
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class Bunch(object):
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"""
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A bunch of threads.
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"""
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def __init__(self, f, n, wait_before_exit=False):
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"""
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Construct a bunch of `n` threads running the same function `f`.
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If `wait_before_exit` is True, the threads won't terminate until
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do_finish() is called.
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"""
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self.f = f
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self.n = n
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self.started = []
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self.finished = []
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self._can_exit = not wait_before_exit
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def task():
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tid = get_ident()
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self.started.append(tid)
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try:
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f()
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finally:
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self.finished.append(tid)
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while not self._can_exit:
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_wait()
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try:
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for i in range(n):
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start_new_thread(task, ())
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except:
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self._can_exit = True
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raise
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def wait_for_started(self):
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while len(self.started) < self.n:
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_wait()
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def wait_for_finished(self):
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while len(self.finished) < self.n:
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_wait()
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def do_finish(self):
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self._can_exit = True
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class BaseTestCase(unittest.TestCase):
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def setUp(self):
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self._threads = support.threading_setup()
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def tearDown(self):
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support.threading_cleanup(*self._threads)
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support.reap_children()
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class BaseLockTests(BaseTestCase):
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"""
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Tests for both recursive and non-recursive locks.
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"""
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def test_constructor(self):
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lock = self.locktype()
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del lock
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def test_acquire_destroy(self):
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lock = self.locktype()
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lock.acquire()
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del lock
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def test_acquire_release(self):
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lock = self.locktype()
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lock.acquire()
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lock.release()
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del lock
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def test_try_acquire(self):
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lock = self.locktype()
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self.assertTrue(lock.acquire(False))
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lock.release()
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def test_try_acquire_contended(self):
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lock = self.locktype()
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lock.acquire()
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result = []
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def f():
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result.append(lock.acquire(False))
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Bunch(f, 1).wait_for_finished()
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self.assertFalse(result[0])
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lock.release()
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def test_acquire_contended(self):
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lock = self.locktype()
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lock.acquire()
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N = 5
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def f():
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lock.acquire()
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lock.release()
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b = Bunch(f, N)
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b.wait_for_started()
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_wait()
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self.assertEqual(len(b.finished), 0)
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lock.release()
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b.wait_for_finished()
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self.assertEqual(len(b.finished), N)
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def test_with(self):
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lock = self.locktype()
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def f():
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lock.acquire()
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lock.release()
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def _with(err=None):
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with lock:
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if err is not None:
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raise err
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_with()
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# Check the lock is unacquired
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Bunch(f, 1).wait_for_finished()
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self.assertRaises(TypeError, _with, TypeError)
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# Check the lock is unacquired
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Bunch(f, 1).wait_for_finished()
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def test_thread_leak(self):
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# The lock shouldn't leak a Thread instance when used from a foreign
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# (non-threading) thread.
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lock = self.locktype()
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def f():
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lock.acquire()
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lock.release()
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n = len(threading.enumerate())
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# We run many threads in the hope that existing threads ids won't
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# be recycled.
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Bunch(f, 15).wait_for_finished()
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self.assertEqual(n, len(threading.enumerate()))
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class LockTests(BaseLockTests):
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"""
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Tests for non-recursive, weak locks
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(which can be acquired and released from different threads).
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"""
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def test_reacquire(self):
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# Lock needs to be released before re-acquiring.
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lock = self.locktype()
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phase = []
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def f():
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lock.acquire()
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phase.append(None)
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lock.acquire()
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phase.append(None)
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start_new_thread(f, ())
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while len(phase) == 0:
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_wait()
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_wait()
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self.assertEqual(len(phase), 1)
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lock.release()
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while len(phase) == 1:
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_wait()
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self.assertEqual(len(phase), 2)
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def test_different_thread(self):
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# Lock can be released from a different thread.
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lock = self.locktype()
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lock.acquire()
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def f():
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lock.release()
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b = Bunch(f, 1)
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b.wait_for_finished()
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lock.acquire()
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lock.release()
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class RLockTests(BaseLockTests):
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"""
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Tests for recursive locks.
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"""
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def test_reacquire(self):
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lock = self.locktype()
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lock.acquire()
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lock.acquire()
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lock.release()
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lock.acquire()
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lock.release()
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lock.release()
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def test_release_unacquired(self):
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# Cannot release an unacquired lock
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lock = self.locktype()
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self.assertRaises(RuntimeError, lock.release)
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lock.acquire()
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lock.acquire()
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lock.release()
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lock.acquire()
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lock.release()
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lock.release()
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self.assertRaises(RuntimeError, lock.release)
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def test_different_thread(self):
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# Cannot release from a different thread
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lock = self.locktype()
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def f():
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lock.acquire()
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b = Bunch(f, 1, True)
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try:
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self.assertRaises(RuntimeError, lock.release)
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finally:
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b.do_finish()
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def test__is_owned(self):
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lock = self.locktype()
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self.assertFalse(lock._is_owned())
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lock.acquire()
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self.assertTrue(lock._is_owned())
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lock.acquire()
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self.assertTrue(lock._is_owned())
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result = []
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def f():
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result.append(lock._is_owned())
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Bunch(f, 1).wait_for_finished()
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self.assertFalse(result[0])
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lock.release()
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self.assertTrue(lock._is_owned())
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lock.release()
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self.assertFalse(lock._is_owned())
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class EventTests(BaseTestCase):
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"""
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Tests for Event objects.
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"""
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def test_is_set(self):
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evt = self.eventtype()
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self.assertFalse(evt.is_set())
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evt.set()
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self.assertTrue(evt.is_set())
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evt.set()
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self.assertTrue(evt.is_set())
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evt.clear()
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self.assertFalse(evt.is_set())
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evt.clear()
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self.assertFalse(evt.is_set())
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def _check_notify(self, evt):
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# All threads get notified
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N = 5
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results1 = []
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results2 = []
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def f():
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results1.append(evt.wait())
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results2.append(evt.wait())
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b = Bunch(f, N)
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b.wait_for_started()
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_wait()
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self.assertEqual(len(results1), 0)
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evt.set()
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b.wait_for_finished()
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self.assertEqual(results1, [True] * N)
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self.assertEqual(results2, [True] * N)
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def test_notify(self):
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evt = self.eventtype()
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self._check_notify(evt)
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# Another time, after an explicit clear()
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evt.set()
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evt.clear()
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self._check_notify(evt)
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def test_timeout(self):
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evt = self.eventtype()
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results1 = []
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results2 = []
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N = 5
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def f():
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results1.append(evt.wait(0.0))
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t1 = time.time()
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r = evt.wait(0.2)
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t2 = time.time()
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results2.append((r, t2 - t1))
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Bunch(f, N).wait_for_finished()
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self.assertEqual(results1, [False] * N)
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for r, dt in results2:
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self.assertFalse(r)
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self.assertTrue(dt >= 0.2, dt)
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# The event is set
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results1 = []
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results2 = []
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evt.set()
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Bunch(f, N).wait_for_finished()
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self.assertEqual(results1, [True] * N)
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for r, dt in results2:
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self.assertTrue(r)
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def test_reset_internal_locks(self):
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evt = self.eventtype()
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old_lock = evt._Event__cond._Condition__lock
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evt._reset_internal_locks()
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new_lock = evt._Event__cond._Condition__lock
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self.assertIsNot(new_lock, old_lock)
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self.assertIs(type(new_lock), type(old_lock))
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class ConditionTests(BaseTestCase):
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"""
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Tests for condition variables.
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"""
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def test_acquire(self):
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cond = self.condtype()
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# Be default we have an RLock: the condition can be acquired multiple
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# times.
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cond.acquire()
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cond.acquire()
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cond.release()
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cond.release()
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lock = threading.Lock()
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cond = self.condtype(lock)
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cond.acquire()
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self.assertFalse(lock.acquire(False))
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cond.release()
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self.assertTrue(lock.acquire(False))
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self.assertFalse(cond.acquire(False))
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lock.release()
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with cond:
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self.assertFalse(lock.acquire(False))
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def test_unacquired_wait(self):
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cond = self.condtype()
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self.assertRaises(RuntimeError, cond.wait)
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def test_unacquired_notify(self):
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cond = self.condtype()
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self.assertRaises(RuntimeError, cond.notify)
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def _check_notify(self, cond):
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# Note that this test is sensitive to timing. If the worker threads
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# don't execute in a timely fashion, the main thread may think they
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# are further along then they are. The main thread therefore issues
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# _wait() statements to try to make sure that it doesn't race ahead
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# of the workers.
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# Secondly, this test assumes that condition variables are not subject
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# to spurious wakeups. The absence of spurious wakeups is an implementation
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# detail of Condition Cariables in current CPython, but in general, not
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# a guaranteed property of condition variables as a programming
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# construct. In particular, it is possible that this can no longer
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# be conveniently guaranteed should their implementation ever change.
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N = 5
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ready = []
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results1 = []
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results2 = []
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phase_num = 0
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def f():
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cond.acquire()
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ready.append(phase_num)
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cond.wait()
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cond.release()
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results1.append(phase_num)
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cond.acquire()
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ready.append(phase_num)
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cond.wait()
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cond.release()
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results2.append(phase_num)
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b = Bunch(f, N)
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b.wait_for_started()
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# first wait, to ensure all workers settle into cond.wait() before
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# we continue. See issues #8799 and #30727.
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while len(ready) < 5:
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_wait()
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ready = []
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self.assertEqual(results1, [])
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# Notify 3 threads at first
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cond.acquire()
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cond.notify(3)
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_wait()
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phase_num = 1
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cond.release()
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while len(results1) < 3:
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_wait()
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self.assertEqual(results1, [1] * 3)
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self.assertEqual(results2, [])
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# make sure all awaken workers settle into cond.wait()
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while len(ready) < 3:
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_wait()
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# Notify 5 threads: they might be in their first or second wait
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cond.acquire()
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cond.notify(5)
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_wait()
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phase_num = 2
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cond.release()
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while len(results1) + len(results2) < 8:
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_wait()
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self.assertEqual(results1, [1] * 3 + [2] * 2)
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self.assertEqual(results2, [2] * 3)
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# make sure all workers settle into cond.wait()
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while len(ready) < 5:
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_wait()
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# Notify all threads: they are all in their second wait
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cond.acquire()
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cond.notify_all()
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_wait()
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phase_num = 3
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cond.release()
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while len(results2) < 5:
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_wait()
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self.assertEqual(results1, [1] * 3 + [2] * 2)
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self.assertEqual(results2, [2] * 3 + [3] * 2)
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b.wait_for_finished()
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def test_notify(self):
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cond = self.condtype()
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self._check_notify(cond)
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# A second time, to check internal state is still ok.
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self._check_notify(cond)
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def test_timeout(self):
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cond = self.condtype()
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results = []
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N = 5
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def f():
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cond.acquire()
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t1 = time.time()
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cond.wait(0.2)
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t2 = time.time()
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cond.release()
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results.append(t2 - t1)
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Bunch(f, N).wait_for_finished()
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self.assertEqual(len(results), 5)
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for dt in results:
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self.assertTrue(dt >= 0.2, dt)
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|
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class BaseSemaphoreTests(BaseTestCase):
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"""
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Common tests for {bounded, unbounded} semaphore objects.
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"""
|
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def test_constructor(self):
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self.assertRaises(ValueError, self.semtype, value = -1)
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self.assertRaises(ValueError, self.semtype, value = -sys.maxint)
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def test_acquire(self):
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sem = self.semtype(1)
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sem.acquire()
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sem.release()
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sem = self.semtype(2)
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sem.acquire()
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sem.acquire()
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sem.release()
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sem.release()
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def test_acquire_destroy(self):
|
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sem = self.semtype()
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sem.acquire()
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del sem
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|
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def test_acquire_contended(self):
|
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sem = self.semtype(7)
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sem.acquire()
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N = 10
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results1 = []
|
|
results2 = []
|
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phase_num = 0
|
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def f():
|
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sem.acquire()
|
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results1.append(phase_num)
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sem.acquire()
|
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results2.append(phase_num)
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b = Bunch(f, 10)
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b.wait_for_started()
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while len(results1) + len(results2) < 6:
|
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_wait()
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self.assertEqual(results1 + results2, [0] * 6)
|
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phase_num = 1
|
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for i in range(7):
|
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sem.release()
|
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while len(results1) + len(results2) < 13:
|
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_wait()
|
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self.assertEqual(sorted(results1 + results2), [0] * 6 + [1] * 7)
|
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phase_num = 2
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for i in range(6):
|
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sem.release()
|
|
while len(results1) + len(results2) < 19:
|
|
_wait()
|
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self.assertEqual(sorted(results1 + results2), [0] * 6 + [1] * 7 + [2] * 6)
|
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# The semaphore is still locked
|
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self.assertFalse(sem.acquire(False))
|
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# Final release, to let the last thread finish
|
|
sem.release()
|
|
b.wait_for_finished()
|
|
|
|
def test_try_acquire(self):
|
|
sem = self.semtype(2)
|
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self.assertTrue(sem.acquire(False))
|
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self.assertTrue(sem.acquire(False))
|
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self.assertFalse(sem.acquire(False))
|
|
sem.release()
|
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self.assertTrue(sem.acquire(False))
|
|
|
|
def test_try_acquire_contended(self):
|
|
sem = self.semtype(4)
|
|
sem.acquire()
|
|
results = []
|
|
def f():
|
|
results.append(sem.acquire(False))
|
|
results.append(sem.acquire(False))
|
|
Bunch(f, 5).wait_for_finished()
|
|
# There can be a thread switch between acquiring the semaphore and
|
|
# appending the result, therefore results will not necessarily be
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# ordered.
|
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self.assertEqual(sorted(results), [False] * 7 + [True] * 3 )
|
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|
|
def test_default_value(self):
|
|
# The default initial value is 1.
|
|
sem = self.semtype()
|
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sem.acquire()
|
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def f():
|
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sem.acquire()
|
|
sem.release()
|
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b = Bunch(f, 1)
|
|
b.wait_for_started()
|
|
_wait()
|
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self.assertFalse(b.finished)
|
|
sem.release()
|
|
b.wait_for_finished()
|
|
|
|
def test_with(self):
|
|
sem = self.semtype(2)
|
|
def _with(err=None):
|
|
with sem:
|
|
self.assertTrue(sem.acquire(False))
|
|
sem.release()
|
|
with sem:
|
|
self.assertFalse(sem.acquire(False))
|
|
if err:
|
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raise err
|
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_with()
|
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self.assertTrue(sem.acquire(False))
|
|
sem.release()
|
|
self.assertRaises(TypeError, _with, TypeError)
|
|
self.assertTrue(sem.acquire(False))
|
|
sem.release()
|
|
|
|
class SemaphoreTests(BaseSemaphoreTests):
|
|
"""
|
|
Tests for unbounded semaphores.
|
|
"""
|
|
|
|
def test_release_unacquired(self):
|
|
# Unbounded releases are allowed and increment the semaphore's value
|
|
sem = self.semtype(1)
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sem.release()
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sem.acquire()
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|
sem.acquire()
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|
sem.release()
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|
|
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class BoundedSemaphoreTests(BaseSemaphoreTests):
|
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"""
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|
Tests for bounded semaphores.
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|
"""
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|
|
|
def test_release_unacquired(self):
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|
# Cannot go past the initial value
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|
sem = self.semtype()
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|
self.assertRaises(ValueError, sem.release)
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|
sem.acquire()
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|
sem.release()
|
|
self.assertRaises(ValueError, sem.release)
|