summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_queue.py
blob: 0c8093a2a9e43182b2939b3ec8f2e62cabefc76f (plain)
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
# Some simple queue module tests, plus some failure conditions
# to ensure the Queue locks remain stable.
import queue
import time
import unittest
from test import support
threading = support.import_module('threading')

QUEUE_SIZE = 5

def qfull(q):
    return q.maxsize > 0 and q.qsize() == q.maxsize

# 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 do_exceptional_blocking_test()
# instead.

class BlockingTestMixin:

    def do_blocking_test(self, block_func, block_args, trigger_func, trigger_args):
        self.t = _TriggerThread(trigger_func, trigger_args)
        self.t.start()
        self.result = block_func(*block_args)
        # If block_func returned before our thread made the call, we failed!
        if not self.t.startedEvent.is_set():
            self.fail("blocking function '%r' appeared not to block" %
                      block_func)
        self.t.join(10) # make sure the thread terminates
        if self.t.is_alive():
            self.fail("trigger function '%r' appeared to not return" %
                      trigger_func)
        return self.result

    # Call this instead if block_func is supposed to raise an exception.
    def do_exceptional_blocking_test(self,block_func, block_args, trigger_func,
                                   trigger_args, expected_exception_class):
        self.t = _TriggerThread(trigger_func, trigger_args)
        self.t.start()
        try:
            try:
                block_func(*block_args)
            except expected_exception_class:
                raise
            else:
                self.fail("expected exception of kind %r" %
                                 expected_exception_class)
        finally:
            self.t.join(10) # make sure the thread terminates
            if self.t.is_alive():
                self.fail("trigger function '%r' appeared to not return" %
                                 trigger_func)
            if not self.t.startedEvent.is_set():
                self.fail("trigger thread ended but event never set")


class BaseQueueTest(unittest.TestCase, BlockingTestMixin):
    def setUp(self):
        self.cum = 0
        self.cumlock = threading.Lock()

    def simple_queue_test(self, q):
        if q.qsize():
            raise RuntimeError("Call this function with an empty queue")
        self.assertTrue(q.empty())
        self.assertFalse(q.full())
        # I guess we better check things actually queue correctly a little :)
        q.put(111)
        q.put(333)
        q.put(222)
        target_order = dict(Queue = [111, 333, 222],
                            LifoQueue = [222, 333, 111],
                            PriorityQueue = [111, 222, 333])
        actual_order = [q.get(), q.get(), q.get()]
        self.assertEquals(actual_order, target_order[q.__class__.__name__],
                          "Didn't seem to queue the correct data!")
        for i in range(QUEUE_SIZE-1):
            q.put(i)
            self.assertTrue(q.qsize(), "Queue should not be empty")
        self.assertTrue(not qfull(q), "Queue should not be full")
        last = 2 * QUEUE_SIZE
        full = 3 * 2 * QUEUE_SIZE
        q.put(last)
        self.assertTrue(qfull(q), "Queue should be full")
        self.assertFalse(q.empty())
        self.assertTrue(q.full())
        try:
            q.put(full, block=0)
            self.fail("Didn't appear to block with a full queue")
        except queue.Full:
            pass
        try:
            q.put(full, timeout=0.01)
            self.fail("Didn't appear to time-out with a full queue")
        except queue.Full:
            pass
        # Test a blocking put
        self.do_blocking_test(q.put, (full,), q.get, ())
        self.do_blocking_test(q.put, (full, True, 10), q.get, ())
        # Empty it
        for i in range(QUEUE_SIZE):
            q.get()
        self.assertTrue(not q.qsize(), "Queue should be empty")
        try:
            q.get(block=0)
            self.fail("Didn't appear to block with an empty queue")
        except queue.Empty:
            pass
        try:
            q.get(timeout=0.01)
            self.fail("Didn't appear to time-out with an empty queue")
        except queue.Empty:
            pass
        # Test a blocking get
        self.do_blocking_test(q.get, (), q.put, ('empty',))
        self.do_blocking_test(q.get, (True, 10), q.put, ('empty',))


    def worker(self, q):
        while True:
            x = q.get()
            if x < 0:
                q.task_done()
                return
            with self.cumlock:
                self.cum += x
            q.task_done()

    def queue_join_test(self, q):
        self.cum = 0
        for i in (0,1):
            threading.Thread(target=self.worker, args=(q,)).start()
        for i in range(100):
            q.put(i)
        q.join()
        self.assertEquals(self.cum, sum(range(100)),
                          "q.join() did not block until all tasks were done")
        for i in (0,1):
            q.put(-1)         # instruct the threads to close
        q.join()                # verify that you can join twice

    def test_queue_task_done(self):
        # Test to make sure a queue task completed successfully.
        q = self.type2test()
        try:
            q.task_done()
        except ValueError:
            pass
        else:
            self.fail("Did not detect task count going negative")

    def test_queue_join(self):
        # Test that a queue join()s successfully, and before anything else
        # (done twice for insurance).
        q = self.type2test()
        self.queue_join_test(q)
        self.queue_join_test(q)
        try:
            q.task_done()
        except ValueError:
            pass
        else:
            self.fail("Did not detect task count going negative")

    def test_simple_queue(self):
        # Do it a couple of times on the same queue.
        # Done twice to make sure works with same instance reused.
        q = self.type2test(QUEUE_SIZE)
        self.simple_queue_test(q)
        self.simple_queue_test(q)

    def test_negative_timeout_raises_exception(self):
        q = self.type2test(QUEUE_SIZE)
        with self.assertRaises(ValueError):
            q.put(1, timeout=-1)
        with self.assertRaises(ValueError):
            q.get(1, timeout=-1)

    def test_nowait(self):
        q = self.type2test(QUEUE_SIZE)
        for i in range(QUEUE_SIZE):
            q.put_nowait(1)
        with self.assertRaises(queue.Full):
            q.put_nowait(1)

        for i in range(QUEUE_SIZE):
            q.get_nowait()
        with self.assertRaises(queue.Empty):
            q.get_nowait()


class QueueTest(BaseQueueTest):
    type2test = queue.Queue

class LifoQueueTest(BaseQueueTest):
    type2test = queue.LifoQueue

class PriorityQueueTest(BaseQueueTest):
    type2test = queue.PriorityQueue



# 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)

class FailingQueueTest(unittest.TestCase, BlockingTestMixin):

    def failing_queue_test(self, q):
        if q.qsize():
            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)
            self.fail("The queue didn't fail when it should have")
        except FailingQueueException:
            pass
        q.fail_next_put = True
        try:
            q.put("oops", timeout=0.1)
            self.fail("The queue didn't fail when it should have")
        except FailingQueueException:
            pass
        q.put("last")
        self.assertTrue(qfull(q), "Queue should be full")
        # Test a failing blocking put
        q.fail_next_put = True
        try:
            self.do_blocking_test(q.put, ("full",), q.get, ())
            self.fail("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:
            self.do_exceptional_blocking_test(q.put, ("full", True, 10), q.get, (),
                                              FailingQueueException)
            self.fail("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")
        self.assertTrue(qfull(q), "Queue should be full")
        q.get()
        self.assertTrue(not qfull(q), "Queue should not be full")
        q.put("last")
        self.assertTrue(qfull(q), "Queue should be full")
        # Test a blocking put
        self.do_blocking_test(q.put, ("full",), q.get, ())
        # Empty it
        for i in range(QUEUE_SIZE):
            q.get()
        self.assertTrue(not q.qsize(), "Queue should be empty")
        q.put("first")
        q.fail_next_get = True
        try:
            q.get()
            self.fail("The queue didn't fail when it should have")
        except FailingQueueException:
            pass
        self.assertTrue(q.qsize(), "Queue should not be empty")
        q.fail_next_get = True
        try:
            q.get(timeout=0.1)
            self.fail("The queue didn't fail when it should have")
        except FailingQueueException:
            pass
        self.assertTrue(q.qsize(), "Queue should not be empty")
        q.get()
        self.assertTrue(not q.qsize(), "Queue should be empty")
        q.fail_next_get = True
        try:
            self.do_exceptional_blocking_test(q.get, (), q.put, ('empty',),
                                              FailingQueueException)
            self.fail("The queue didn't fail when it should have")
        except FailingQueueException:
            pass
        # put succeeded, but get failed.
        self.assertTrue(q.qsize(), "Queue should not be empty")
        q.get()
        self.assertTrue(not q.qsize(), "Queue should be empty")

    def test_failing_queue(self):
        # Test to make sure a queue is functioning correctly.
        # Done twice to the same instance.
        q = FailingQueue(QUEUE_SIZE)
        self.failing_queue_test(q)
        self.failing_queue_test(q)


def test_main():
    support.run_unittest(QueueTest, LifoQueueTest, PriorityQueueTest,
                              FailingQueueTest)


if __name__ == "__main__":
    test_main()