-
-
Notifications
You must be signed in to change notification settings - Fork 34.3k
Expand file tree
/
Copy pathlock_tests.py
More file actions
1265 lines (1075 loc) · 37.4 KB
/
lock_tests.py
File metadata and controls
1265 lines (1075 loc) · 37.4 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
"""
Various tests for synchronization primitives.
"""
import gc
import sys
import time
from _thread import start_new_thread, TIMEOUT_MAX
import threading
import unittest
import weakref
from test import support
from test.support import threading_helper
requires_fork = unittest.skipUnless(support.has_fork_support,
"platform doesn't support fork "
"(no _at_fork_reinit method)")
def wait_threads_blocked(nthread):
# Arbitrary sleep to wait until N threads are blocked,
# like waiting for a lock.
time.sleep(0.010 * nthread)
class Bunch(object):
"""
A bunch of threads.
"""
def __init__(self, func, nthread, wait_before_exit=False):
"""
Construct a bunch of `nthread` threads running the same function `func`.
If `wait_before_exit` is True, the threads won't terminate until
do_finish() is called.
"""
self.func = func
self.nthread = nthread
self.started = []
self.finished = []
self.exceptions = []
self._can_exit = not wait_before_exit
self._wait_thread = None
def task(self):
tid = threading.get_ident()
self.started.append(tid)
try:
self.func()
except BaseException as exc:
self.exceptions.append(exc)
finally:
self.finished.append(tid)
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if self._can_exit:
break
def __enter__(self):
self._wait_thread = threading_helper.wait_threads_exit(support.SHORT_TIMEOUT)
self._wait_thread.__enter__()
try:
for _ in range(self.nthread):
start_new_thread(self.task, ())
except:
self._can_exit = True
raise
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(self.started) >= self.nthread:
break
return self
def __exit__(self, exc_type, exc_value, traceback):
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(self.finished) >= self.nthread:
break
# Wait until threads completely exit according to _thread._count()
self._wait_thread.__exit__(None, None, None)
# Break reference cycle
exceptions = self.exceptions
self.exceptions = None
if exceptions:
raise ExceptionGroup(f"{self.func} threads raised exceptions",
exceptions)
def do_finish(self):
self._can_exit = True
class BaseTestCase(unittest.TestCase):
def setUp(self):
self._threads = threading_helper.threading_s
BEA4
etup()
def tearDown(self):
threading_helper.threading_cleanup(*self._threads)
support.reap_children()
def assertTimeout(self, actual, expected):
# The waiting and/or time.monotonic() can be imprecise, which
# is why comparing to the expected value would sometimes fail
# (especially under Windows).
self.assertGreaterEqual(actual, expected * 0.6)
# Test nothing insane happened
self.assertLess(actual, expected * 10.0)
class BaseLockTests(BaseTestCase):
"""
Tests for both recursive and non-recursive locks.
"""
def wait_phase(self, phase, expected):
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(phase) >= expected:
break
self.assertEqual(len(phase), expected)
def test_constructor(self):
lock = self.locktype()
del lock
def test_constructor_noargs(self):
self.assertRaises(TypeError, self.locktype, 1)
self.assertRaises(TypeError, self.locktype, x=1)
self.assertRaises(TypeError, self.locktype, 1, x=2)
def test_repr(self):
lock = self.locktype()
self.assertRegex(repr(lock), "<unlocked .* object (.*)?at .*>")
del lock
def test_locked_repr(self):
lock = self.locktype()
lock.acquire()
self.assertRegex(repr(lock), "<locked .* object (.*)?at .*>")
del lock
def test_acquire_destroy(self):
lock = self.locktype()
lock.acquire()
del lock
def test_acquire_release(self):
lock = self.locktype()
lock.acquire()
lock.release()
del lock
def test_try_acquire(self):
lock = self.locktype()
self.assertTrue(lock.acquire(False))
lock.release()
def test_try_acquire_contended(self):
lock = self.locktype()
lock.acquire()
result = []
def f():
result.append(lock.acquire(False))
with Bunch(f, 1):
pass
self.assertFalse(result[0])
lock.release()
def test_acquire_contended(self):
lock = self.locktype()
lock.acquire()
def f():
lock.acquire()
lock.release()
N = 5
with Bunch(f, N) as bunch:
# Threads block on lock.acquire()
wait_threads_blocked(N)
self.assertEqual(len(bunch.finished), 0)
# Threads unblocked
lock.release()
self.assertEqual(len(bunch.finished), N)
def test_with(self):
lock = self.locktype()
def f():
lock.acquire()
lock.release()
def with_lock(err=None):
with lock:
if err is not None:
raise err
# Acquire the lock, do nothing, with releases the lock
with lock:
pass
# Check that the lock is unacquired
with Bunch(f, 1):
pass
# Acquire the lock, raise an exception, with releases the lock
with self.assertRaises(TypeError):
with lock:
raise TypeError
# Check that the lock is unacquired even if after an exception
# was raised in the previous "with lock:" block
with Bunch(f, 1):
pass
def test_thread_leak(self):
# The lock shouldn't leak a Thread instance when used from a foreign
# (non-threading) thread.
lock = self.locktype()
def f():
lock.acquire()
lock.release()
# We run many threads in the hope that existing threads ids won't
# be recycled.
with Bunch(f, 15):
pass
def test_timeout(self):
lock = self.locktype()
# Can't set timeout if not blocking
self.assertRaises(ValueError, lock.acquire, False, 1)
# Invalid timeout values
self.assertRaises(ValueError, lock.acquire, timeout=-100)
self.assertRaises(OverflowError, lock.acquire, timeout=1e100)
self.assertRaises(OverflowError, lock.acquire, timeout=TIMEOUT_MAX + 1)
# TIMEOUT_MAX is ok
lock.acquire(timeout=TIMEOUT_MAX)
lock.release()
t1 = time.monotonic()
self.assertTrue(lock.acquire(timeout=5))
t2 = time.monotonic()
# Just a sanity test that it didn't actually wait for the timeout.
self.assertLess(t2 - t1, 5)
results = []
def f():
t1 = time.monotonic()
results.append(lock.acquire(timeout=0.5))
t2 = time.monotonic()
results.append(t2 - t1)
with Bunch(f, 1):
pass
self.assertFalse(results[0])
self.assertTimeout(results[1], 0.5)
def test_weakref_exists(self):
lock = self.locktype()
ref = weakref.ref(lock)
self.assertIsNotNone(ref())
def test_weakref_deleted(self):
lock = self.locktype()
ref = weakref.ref(lock)
del lock
gc.collect() # For PyPy or other GCs.
self.assertIsNone(ref())
class LockTests(BaseLockTests):
"""
Tests for non-recursive, weak locks
(which can be acquired and released from different threads).
"""
def test_reacquire(self):
# Lock needs to be released before re-acquiring.
lock = self.locktype()
phase = []
def f():
lock.acquire()
phase.append(None)
lock.acquire()
phase.append(None)
with threading_helper.wait_threads_exit():
# Thread blocked on lock.acquire()
start_new_thread(f, ())
self.wait_phase(phase, 1)
# Thread unblocked
lock.release()
self.wait_phase(phase, 2)
def test_different_thread(self):
# Lock can be released from a different thread.
lock = self.locktype()
lock.acquire()
def f():
lock.release()
with Bunch(f, 1):
pass
lock.acquire()
lock.release()
def test_state_after_timeout(self):
# Issue #11618: check that lock is in a proper state after a
# (non-zero) timeout.
lock = self.locktype()
lock.acquire()
self.assertFalse(lock.acquire(timeout=0.01))
lock.release()
self.assertFalse(lock.locked())
self.assertTrue(lock.acquire(blocking=False))
@requires_fork
def test_at_fork_reinit(self):
def use_lock(lock):
# make sure that the lock still works normally
# after _at_fork_reinit()
lock.acquire()
lock.release()
# unlocked
lock = self.locktype()
lock._at_fork_reinit()
use_lock(lock)
# locked: _at_fork_reinit() resets the lock to the unlocked state
lock2 = self.locktype()
lock2.acquire()
lock2._at_fork_reinit()
use_lock(lock2)
class RLockTests(BaseLockTests):
"""
Tests for recursive locks.
"""
def test_repr_count(self):
# see gh-134322: check that count values are correct:
# when a rlock is just created,
# in a second thread when rlock is acquired in the main thread.
lock = self.locktype()
self.assertIn("count=0", repr(lock))
self.assertIn("<unlocked", repr(lock))
lock.acquire()
lock.acquire()
self.assertIn("count=2", repr(lock))
self.assertIn("<locked", repr(lock))
result = []
def call_repr():
result.append(repr(lock))
with Bunch(call_repr, 1):
pass
self.assertIn("count=2", result[0])
self.assertIn("<locked", result[0])
def test_reacquire(self):
lock = self.locktype()
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
def test_release_unacquired(self):
# Cannot release an unacquired lock
lock = self.locktype()
self.assertRaises(RuntimeError, lock.release)
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
self.assertRaises(RuntimeError, lock.release)
def test_locked(self):
lock = self.locktype()
self.assertFalse(lock.locked())
lock.acquire()
self.assertTrue(lock.locked())
lock.acquire()
self.assertTrue(lock.locked())
lock.release()
self.assertTrue(lock.locked())
lock.release()
self.assertFalse(lock.locked())
def test_locked_with_2threads(self):
# see gh-134323: check that a rlock which
# is acquired in a different thread,
# is still locked in the main thread.
result = []
rlock = self.locktype()
self.assertFalse(rlock.locked())
def acquire():
result.append(rlock.locked())
rlock.acquire()
result.append(rlock.locked())
with Bunch(acquire, 1):
pass
self.assertTrue(rlock.locked())
self.assertFalse(result[0])
self.assertTrue(result[1])
def test_release_save_unacquired(self):
# Cannot _release_save an unacquired lock
lock = self.locktype()
self.assertRaises(RuntimeError, lock._release_save)
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
self.assertRaises(RuntimeError, lock._release_save)
def test_recursion_count(self):
lock = self.locktype()
self.assertEqual(0, lock._recursion_count())
lock.acquire()
self.assertEqual(1, lock._recursion_count())
lock.acquire()
lock.acquire()
self.assertEqual(3, lock._recursion_count())
lock.release()
self.assertEqual(2, lock._recursion_count())
lock.release()
lock.release()
self.assertEqual(0, lock._recursion_count())
phase = []
def f():
lock.acquire()
phase.append(None)
self.wait_phase(phase, 2)
lock.release()
phase.append(None)
with threading_helper.wait_threads_exit():
# Thread blocked on lock.acquire()
start_new_thread(f, ())
self.wait_phase(phase, 1)
self.assertEqual(0, lock._recursion_count())
# Thread unblocked
phase.append(None)
self.wait_phase(phase, 3)
self.assertEqual(0, lock._recursion_count())
def test_different_thread(self):
# Cannot release from a different thread
lock = self.locktype()
def f():
lock.acquire()
with Bunch(f, 1, True) as bunch:
try:
self.assertRaises(RuntimeError, lock.release)
finally:
bunch.do_finish()
def test__is_owned(self):
lock = self.locktype()
self.assertFalse(lock._is_owned())
lock.acquire()
self.assertTrue(lock._is_owned())
lock.acquire()
self.assertTrue(lock._is_owned())
result = []
def f():
result.append(lock._is_owned())
with Bunch(f, 1):
pass
self.assertFalse(result[0])
lock.release()
self.assertTrue(lock._is_owned())
lock.release()
self.assertFalse(lock._is_owned())
class EventTests(BaseTestCase):
"""
Tests for Event objects.
"""
def test_is_set(self):
evt = self.eventtype()
self.assertFalse(evt.is_set())
evt.set()
self.assertTrue(evt.is_set())
evt.set()
self.assertTrue(evt.is_set())
evt.clear()
self.assertFalse(evt.is_set())
evt.clear()
self.assertFalse(evt.is_set())
def _check_notify(self, evt):
# All threads get notified
N = 5
results1 = []
results2 = []
def f():
results1.append(evt.wait())
results2.append(evt.wait())
with Bunch(f, N):
# Threads blocked on first evt.wait()
wait_threads_blocked(N)
self.assertEqual(len(results1), 0)
# Threads unblocked
evt.set()
self.assertEqual(results1, [True] * N)
self.assertEqual(results2, [True] * N)
def test_notify(self):
evt = self.eventtype()
self._check_notify(evt)
# Another time, after an explicit clear()
evt.set()
evt.clear()
self._check_notify(evt)
def test_timeout(self):
evt = self.eventtype()
results1 = []
results2 = []
N = 5
def f():
results1.append(evt.wait(0.0))
t1 = time.monotonic()
r = evt.wait(0.5)
t2 = time.monotonic()
results2.append((r, t2 - t1))
with Bunch(f, N):
pass
self.assertEqual(results1, [False] * N)
for r, dt in results2:
self.assertFalse(r)
self.assertTimeout(dt, 0.5)
# The event is set
results1 = []
results2 = []
evt.set()
with Bunch(f, N):
pass
self.assertEqual(results1, [True] * N)
for r, dt in results2:
self.assertTrue(r)
def test_set_and_clear(self):
# gh-57711: check that wait() returns true even when the event is
# cleared before the waiting thread is woken up.
event = self.eventtype()
results = []
def f():
results.append(event.wait(support.LONG_TIMEOUT))
N = 5
with Bunch(f, N):
# Threads blocked on event.wait()
wait_threads_blocked(N)
# Threads unblocked
event.set()
event.clear()
self.assertEqual(results, [True] * N)
@requires_fork
def test_at_fork_reinit(self):
# ensure that condition is still using a Lock after reset
evt = self.eventtype()
with evt._cond:
self.assertFalse(evt._cond.acquire(False))
evt._at_fork_reinit()
with evt._cond:
self.assertFalse(evt._cond.acquire(False))
def test_repr(self):
evt = self.eventtype()
self.assertRegex(repr(evt), r"<\w+\.Event at .*: unset>")
evt.set()
self.assertRegex(repr(evt), r"<\w+\.Event at .*: set>")
class ConditionTests(BaseTestCase):
"""
Tests for condition variables.
"""
def test_acquire(self):
cond = self.condtype()
# Be default we have an RLock: the condition can be acquired multiple
# times.
cond.acquire()
cond.acquire()
cond.release()
cond.release()
lock = threading.Lock()
cond = self.condtype(lock)
cond.acquire()
self.assertFalse(lock.acquire(False))
cond.release()
self.assertTrue(lock.acquire(False))
self.assertFalse(cond.acquire(False))
lock.release()
with cond:
self.assertFalse(lock.acquire(False))
def test_unacquired_wait(self):
cond = self.condtype()
self.assertRaises(RuntimeError, cond.wait)
def test_unacquired_notify(self):
cond = self.condtype()
self.assertRaises(RuntimeError, cond.notify)
def _check_notify(self, cond):
# Note that this test is sensitive to timing. If the worker threads
# don't execute in a timely fashion, the main thread may think they
# are further along then they are. The main thread therefore issues
# wait_threads_blocked() statements to try to make sure that it doesn't
# race ahead of the workers.
# Secondly, this test assumes that condition variables are not subject
# to spurious wakeups. The absence of spurious wakeups is an implementation
# detail of Condition Variables in current CPython, but in general, not
# a guaranteed property of condition variables as a programming
# construct. In particular, it is possible that this can no longer
# be conveniently guaranteed should their implementation ever change.
ready = []
results1 = []
results2 = []
phase_num = 0
def f():
cond.acquire()
ready.append(phase_num)
result = cond.wait()
cond.release()
results1.append((result, phase_num))
cond.acquire()
ready.append(phase_num)
result = cond.wait()
cond.release()
results2.append((result, phase_num))
N = 5
with Bunch(f, N):
# first wait, to ensure all workers settle into cond.wait() before
# we continue. See issues #8799 and #30727.
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(ready) >= N:
break
ready.clear()
self.assertEqual(results1, [])
# Notify 3 threads at first
count1 = 3
cond.acquire()
cond.notify(count1)
wait_threads_blocked(count1)
# Phase 1
phase_num = 1
cond.release()
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(results1) >= count1:
break
self.assertEqual(results1, [(True, 1)] * count1)
self.assertEqual(results2, [])
# Wait until awaken workers are blocked on cond.wait()
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(ready) >= count1 :
break
# Notify 5 threads: they might be in their first or second wait
cond.acquire()
cond.notify(5)
wait_threads_blocked(N)
# Phase 2
phase_num = 2
cond.release()
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(results1) + len(results2) >= (N + count1):
break
count2 = N - count1
self.assertEqual(results1, [(True, 1)] * count1 + [(True, 2)] * count2)
self.assertEqual(results2, [(True, 2)] * count1)
# Make sure all workers settle into cond.wait()
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(ready) >= N:
break
# Notify all threads: they are all in their second wait
cond.acquire()
cond.notify_all()
wait_threads_blocked(N)
# Phase 3
phase_num = 3
cond.release()
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(results2) >= N:
break
self.assertEqual(results1, [(True, 1)] * count1 + [(True, 2)] * count2)
self.assertEqual(results2, [(True, 2)] * count1 + [(True, 3)] * count2)
def test_notify(self):
cond = self.condtype()
self._check_notify(cond)
# A second time, to check internal state is still ok.
self._check_notify(cond)
def test_timeout(self):
cond = self.condtype()
timeout = 0.5
results = []
def f():
cond.acquire()
t1 = time.monotonic()
result = cond.wait(timeout)
t2 = time.monotonic()
cond.release()
results.append((t2 - t1, result))
N = 5
with Bunch(f, N):
pass
self.assertEqual(len(results), N)
for dt, result in results:
self.assertTimeout(dt, timeout)
# Note that conceptually (that"s the condition variable protocol)
# a wait() may succeed even if no one notifies us and before any
# timeout occurs. Spurious wakeups can occur.
# This makes it hard to verify the result value.
# In practice, this implementation has no spurious wakeups.
self.assertFalse(result)
def test_waitfor(self):
cond = self.condtype()
state = 0
def f():
with cond:
result = cond.wait_for(lambda: state == 4)
self.assertTrue(result)
self.assertEqual(state, 4)
with Bunch(f, 1):
for i in range(4):
time.sleep(0.010)
with cond:
state += 1
cond.notify()
def test_waitfor_timeout(self):
cond = self.condtype()
state = 0
success = []
def f():
with cond:
dt = time.monotonic()
result = cond.wait_for(lambda : state==4, timeout=0.1)
dt = time.monotonic() - dt
self.assertFalse(result)
self.assertTimeout(dt, 0.1)
success.append(None)
with Bunch(f, 1):
# Only increment 3 times, so state == 4 is never reached.
for i in range(3):
time.sleep(0.010)
with cond:
state += 1
cond.notify()
self.assertEqual(len(success), 1)
class BaseSemaphoreTests(BaseTestCase):
"""
Common tests for {bounded, unbounded} semaphore objects.
"""
def test_constructor(self):
self.assertRaises(ValueError, self.semtype, value = -1)
self.assertRaises(ValueError, self.semtype, value = -sys.maxsize)
def test_acquire(self):
sem = self.semtype(1)
sem.acquire()
sem.release()
sem = self.semtype(2)
sem.acquire()
sem.acquire()
sem.release()
sem.release()
def test_acquire_destroy(self):
sem = self.semtype()
sem.acquire()
del sem
def test_acquire_contended(self):
sem_value = 7
sem = self.semtype(sem_value)
sem.acquire()
sem_results = []
results1 = []
results2 = []
phase_num = 0
def func():
sem_results.append(sem.acquire())
results1.append(phase_num)
sem_results.append(sem.acquire())
results2.append(phase_num)
def wait_count(count):
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(results1) + len(results2) >= count:
break
N = 10
with Bunch(func, N):
# Phase 0
count1 = sem_value - 1
wait_count(count1)
self.assertEqual(results1 + results2, [0] * count1)
# Phase 1
phase_num = 1
for i in range(sem_value):
sem.release()
count2 = sem_value
wait_count(count1 + count2)
self.assertEqual(sorted(results1 + results2),
[0] * count1 + [1] * count2)
# Phase 2
phase_num = 2
count3 = (sem_value - 1)
for i in range(count3):
sem.release()
wait_count(count1 + count2 + count3)
self.assertEqual(sorted(results1 + results2),
[0] * count1 + [1] * count2 + [2] * count3)
# The semaphore is still locked
self.assertFalse(sem.acquire(False))
# Final release, to let the last thread finish
count4 = 1
sem.release()
self.assertEqual(sem_results,
[True] * (count1 + count2 + count3 + count4))
def test_multirelease(self):
sem_value = 7
sem = self.semtype(sem_value)
sem.acquire()
results1 = []
results2 = []
phase_num = 0
def func():
sem.acquire()
results1.append(phase_num)
sem.acquire()
results2.append(phase_num)
def wait_count(count):
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(results1) + len(results2) >= count:
break
with Bunch(func, 10):
# Phase 0
count1 = sem_value - 1
wait_count(count1)
self.assertEqual(results1 + results2, [0] * count1)
# Phase 1
phase_num = 1
count2 = sem_value
sem.release(count2)
wait_count(count1 + count2)
self.assertEqual(sorted(results1 + results2),
[0] * count1 + [1] * count2)
# Phase 2
phase_num = 2
count3 = sem_value - 1
sem.release(count3)
wait_count(count1 + count2 + count3)
self.assertEqual(sorted(results1 + results2),
[0] * count1 + [1] * count2 + [2] * count3)
# The semaphore is still locked
self.assertFalse(sem.acquire(False))
# Final release, to let the last thread finish
sem.release()
def test_try_acquire(self):
sem = self.semtype(2)
self.assertTrue(sem.acquire(False))
self.assertTrue(sem.acquire(False))
self.assertFalse(sem.acquire(False))
sem.release()
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))
with Bunch(f, 5):
pass
# There can be a thread switch between acquiring the semaphore and
# appending the result, therefore results will not necessarily be
# ordered.
self.assertEqual(sorted(results), [False] * 7 + [True] * 3 )
def test_acquire_timeout(self):
sem = self.semtype(2)
self.assertRaises(ValueError, sem.acquire, False, timeout=1.0)
self.assertTrue(sem.acquire(timeout=0.005))
self.assertTrue(sem.acquire(timeout=0.005))
self.assertFalse(sem.acquire(timeout=0.005))
sem.release()
self.assertTrue(sem.acquire(timeout=0.005))
t = time.monotonic()
self.assertFalse(sem.acquire(timeout=0.5))
dt = time.monotonic() - t
self.assertTimeout(dt, 0.5)
def test_default_value(self):
# The default initial value is 1.
sem = self.semtype()
sem.acquire()
def f():
sem.acquire()
sem.release()
with Bunch(f, 1) as bunch:
# Thread blocked on sem.acquire()
wait_threads_blocked(1)
self.assertFalse(bunch.finished)
# Thread unblocked
sem.release()
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:
raise err
_with()
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.