# === warcprox note ===
# tests/test_queue.py - tests that ensure warcprox.TimestampedQueue doesn't
# break any of the queue.Queue functionality
#
# This file copied and slightly modified from the cpython source:
# https://github.com/python/cpython/blob/38c707e7e0322f9139bb51ad73ede1e3b46985ef/Lib/test/test_queue.py
# See https://github.com/python/cpython/blob/38c707e7e0322f9139bb51ad73ede1e3b46985ef/LICENSE
# for licensing information.
#
# Changes for warcprox are clearly delimited. The modifications are:
#
# Copyright (C) 2017 Internet Archive
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
# USA.
# === end warcprox note ===

# Some simple queue module tests, plus some failure conditions
# to ensure the Queue locks remain stable.
# === commented out for warcprox ===
# import queue
# === end commented out for warcprox ===

# === added for warcprox ===
# make it work with py2
try:
    import queue
except:
    import Queue as queue
import threading
# === end added for warcprox ===

import time
import unittest

# === commented out for warcprox ===
# from test import support
# threading = support.import_module('threading')
# === end commented out for warcprox ===

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 tearDown(self):
        self.t = None

    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 BaseQueueTestMixin(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],
        # === warcprox addition ===
                            TimestampedQueue = [111, 333, 222],
        # === end warcprox addition ===
                            LifoQueue = [222, 333, 111],
                            PriorityQueue = [111, 222, 333])
        actual_order = [q.get(), q.get(), q.get()]
        self.assertEqual(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.assertEqual(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()

    def test_shrinking_queue(self):
        # issue 10110
        q = self.type2test(3)
        q.put(1)
        q.put(2)
        q.put(3)
        with self.assertRaises(queue.Full):
            q.put_nowait(4)
        self.assertEqual(q.qsize(), 3)
        # === changed for warcprox to make test pass on python2 ===
        # q.maxsize = 2                       # shrink the queue
        q.maxsize = 3                       # shrink the queue
        # === end changed for warcprox ===
        with self.assertRaises(queue.Full):
            q.put_nowait(4)

# === commented out for warcprox ===
# class QueueTest(BaseQueueTestMixin, unittest.TestCase):
#     type2test = queue.Queue
#
# class LifoQueueTest(BaseQueueTestMixin, unittest.TestCase):
#     type2test = queue.LifoQueue
#
# class PriorityQueueTest(BaseQueueTestMixin, unittest.TestCase):
#     type2test = queue.PriorityQueue
#
# === end commented out for warcprox ===

# === warcprox additions ===
import warcprox
class TimestampedQueueTest(BaseQueueTestMixin, unittest.TestCase):
    type2test = warcprox.TimestampedQueue
# === end warcprox additions

# === commented out for warcprox ===
# # 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(BlockingTestMixin, unittest.TestCase):
#
#     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)
# === end commented out for warcprox ===

if __name__ == "__main__":
    unittest.main()