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
|
# Some simple Queue module tests, plus some failure conditions
# to ensure the Queue locks remain stable.
import Queue
import sys
import threading
import time
from test.test_support import verify, TestFailed, verbose
QUEUE_SIZE = 5
# A thread to run a function that unclogs a blocked Queue.
class _TriggerThread(threading.Thread):
def __init__(self, fn, args):
self.fn = fn
self.args = args
self.startedEvent = threading.Event()
threading.Thread.__init__(self)
def run(self):
# The sleep isn't necessary, but is intended to give the blocking
# function in the main thread a chance at actually blocking before
# we unclog it. But if the sleep is longer than the timeout-based
# tests wait in their blocking functions, those tests will fail.
# So we give them much longer timeout values compared to the
# sleep here (I aimed at 10 seconds for blocking functions --
# they should never actually wait that long - they should make
# progress as soon as we call self.fn()).
time.sleep(0.1)
self.startedEvent.set()
self.fn(*self.args)
# Execute a function that blocks, and in a separate thread, a function that
# triggers the release. Returns the result of the blocking function.
# Caution: block_func must guarantee to block until trigger_func is
# called, and trigger_func must guarantee to change queue state so that
# block_func can make enough progress to return. In particular, a
# block_func that just raises an exception regardless of whether trigger_func
# is called will lead to timing-dependent sporadic failures, and one of
# those went rarely seen but undiagnosed for years. Now block_func
# must be unexceptional. If block_func is supposed to raise an exception,
# call _doExceptionalBlockingTest() instead.
def _doBlockingTest(block_func, block_args, trigger_func, trigger_args):
t = _TriggerThread(trigger_func, trigger_args)
t.start()
result = block_func(*block_args)
# If block_func returned before our thread made the call, we failed!
if not t.startedEvent.isSet():
raise TestFailed("blocking function '%r' appeared not to block" %
block_func)
t.join(10) # make sure the thread terminates
if t.isAlive():
raise TestFailed("trigger function '%r' appeared to not return" %
trigger_func)
return result
# Call this instead if block_func is supposed to raise an exception.
def _doExceptionalBlockingTest(block_func, block_args, trigger_func,
trigger_args, expected_exception_class):
t = _TriggerThread(trigger_func, trigger_args)
t.start()
try:
try:
block_func(*block_args)
except expected_exception_class:
raise
else:
raise TestFailed("expected exception of kind %r" %
expected_exception_class)
finally:
t.join(10) # make sure the thread terminates
if t.isAlive():
raise TestFailed("trigger function '%r' appeared to not return" %
trigger_func)
if not t.startedEvent.isSet():
raise TestFailed("trigger thread ended but event never set")
# A Queue subclass that can provoke failure at a moment's notice :)
class FailingQueueException(Exception):
pass
class FailingQueue(Queue.Queue):
def __init__(self, *args):
self.fail_next_put = False
self.fail_next_get = False
Queue.Queue.__init__(self, *args)
def _put(self, item):
if self.fail_next_put:
self.fail_next_put = False
raise FailingQueueException, "You Lose"
return Queue.Queue._put(self, item)
def _get(self):
if self.fail_next_get:
self.fail_next_get = False
raise FailingQueueException, "You Lose"
return Queue.Queue._get(self)
def FailingQueueTest(q):
if not q.empty():
raise RuntimeError, "Call this function with an empty queue"
for i in range(QUEUE_SIZE-1):
q.put(i)
# Test a failing non-blocking put.
q.fail_next_put = True
try:
q.put("oops", block=0)
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
q.fail_next_put = True
try:
q.put("oops", timeout=0.1)
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
q.put("last")
verify(q.full(), "Queue should be full")
# Test a failing blocking put
q.fail_next_put = True
try:
_doBlockingTest(q.put, ("full",), q.get, ())
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
# Check the Queue isn't damaged.
# put failed, but get succeeded - re-add
q.put("last")
# Test a failing timeout put
q.fail_next_put = True
try:
_doExceptionalBlockingTest(q.put, ("full", True, 10), q.get, (),
FailingQueueException)
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
# Check the Queue isn't damaged.
# put failed, but get succeeded - re-add
q.put("last")
verify(q.full(), "Queue should be full")
q.get()
verify(not q.full(), "Queue should not be full")
q.put("last")
verify(q.full(), "Queue should be full")
# Test a blocking put
_doBlockingTest( q.put, ("full",), q.get, ())
# Empty it
for i in range(QUEUE_SIZE):
q.get()
verify(q.empty(), "Queue should be empty")
q.put("first")
q.fail_next_get = True
try:
q.get()
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
verify(not q.empty(), "Queue should not be empty")
q.fail_next_get = True
try:
q.get(timeout=0.1)
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
verify(not q.empty(), "Queue should not be empty")
q.get()
verify(q.empty(), "Queue should be empty")
q.fail_next_get = True
try:
_doExceptionalBlockingTest(q.get, (), q.put, ('empty',),
FailingQueueException)
raise TestFailed("The queue didn't fail when it should have")
except FailingQueueException:
pass
# put succeeded, but get failed.
verify(not q.empty(), "Queue should not be empty")
q.get()
verify(q.empty(), "Queue should be empty")
def SimpleQueueTest(q):
if not q.empty():
raise RuntimeError, "Call this function with an empty queue"
# I guess we better check things actually queue correctly a little :)
q.put(111)
q.put(222)
verify(q.get() == 111 and q.get() == 222,
"Didn't seem to queue the correct data!")
for i in range(QUEUE_SIZE-1):
q.put(i)
verify(not q.empty(), "Queue should not be empty")
verify(not q.full(), "Queue should not be full")
q.put("last")
verify(q.full(), "Queue should be full")
try:
q.put("full", block=0)
raise TestFailed("Didn't appear to block with a full queue")
except Queue.Full:
pass
try:
q.put("full", timeout=0.01)
raise TestFailed("Didn't appear to time-out with a full queue")
except Queue.Full:
pass
# Test a blocking put
_doBlockingTest(q.put, ("full",), q.get, ())
_doBlockingTest(q.put, ("full", True, 10), q.get, ())
# Empty it
for i in range(QUEUE_SIZE):
q.get()
verify(q.empty(), "Queue should be empty")
try:
q.get(block=0)
raise TestFailed("Didn't appear to block with an empty queue")
except Queue.Empty:
pass
try:
q.get(timeout=0.01)
raise TestFailed("Didn't appear to time-out with an empty queue")
except Queue.Empty:
pass
# Test a blocking get
_doBlockingTest(q.get, (), q.put, ('empty',))
_doBlockingTest(q.get, (True, 10), q.put, ('empty',))
def test():
q = Queue.Queue(QUEUE_SIZE)
# Do it a couple of times on the same queue
SimpleQueueTest(q)
SimpleQueueTest(q)
if verbose:
print "Simple Queue tests seemed to work"
q = FailingQueue(QUEUE_SIZE)
FailingQueueTest(q)
FailingQueueTest(q)
if verbose:
print "Failing Queue tests seemed to work"
test()
|
