def collect_tasks(self, test, tasks_queue, tasks_list, to_teardown, result):
        """
        Recursively traverses the test suite tree and either records
        Failure results directly, or recurses into self.collect for
        test suite members that share common fixtures, or adds task
        to the global queue.

        :param test: Test or a collection of test (Test suite)
        :param tasks_queue: List of tuples (task_addr, args)
        :type tasks_queue: list
        :param tasks_list: List of task names task_addr + str(args)
        :type tasks_list: list
        :param to_teardown: List object to be populated with objects to tear down
        :type to_teardown: list
        :param result:
        :type result: TextTestResult
        """

        # Dispatch and collect results
        # It puts indexes only on queue because tests aren't picklable

        self.stream.write("Inspecting test tree for distributable tests...")

        for case in self.get_test_batch(test):
            self.stream.write(".")

            if (isinstance(case, nose.case.Test) and
                isinstance(case.test, failure.Failure)):
                case(result) # run here to capture the failure
                continue

            # handle shared fixtures
            if isinstance(case, ContextSuite) and case.context is failure.Failure:
                case(result) # run here to capture the failure
                continue

            if isinstance(case, ContextSuite) and has_shared_fixtures(case):
                try:
                    case.setUp()
                except (KeyboardInterrupt, SystemExit):
                    raise
                except:
                    result.addError(case, sys.exc_info())
                else:
                    to_teardown.append(case)
                    if case.factory:
                        ancestors = case.factory.context.get(case, [])
                        for ancestor in ancestors[:2]:
                            if getattr(ancestor, '_multiprocess_shared_', False):
                                ancestor._multiprocess_can_split_ = True
                            #ancestor._multiprocess_shared_ = False
                    self.collect_tasks(case, tasks_queue, tasks_list, to_teardown, result)
                continue

            # task_addr is the exact string that was put in tasks_list
            test_addr = add_task_to_queue(case, tasks_queue, tasks_list)
            log.debug("Queued test %s (%s)", len(tasks_list), test_addr)

        self.stream.write(" Found %s test cases\n" % len(tasks_queue))
    def collect(self, test, testQueue, tasks, to_teardown, result):
        # dispatch and collect results
        # put indexes only on queue because tests aren't picklable
        for case in self.nextBatch(test):
            log.debug("Next batch %s (%s)", case, type(case))
            if (isinstance(case, nose.case.Test) and
                isinstance(case.test, failure.Failure)):
                log.debug("Case is a Failure")
                case(result) # run here to capture the failure
                continue
            # handle shared fixtures
            if isinstance(case, ContextSuite) and case.context is failure.Failure:
                log.debug("Case is a Failure")
                case(result) # run here to capture the failure
                continue
            elif isinstance(case, ContextSuite) and self.sharedFixtures(case):
                log.debug("%s has shared fixtures", case)
                try:
                    case.setUp()
                except (KeyboardInterrupt, SystemExit):
                    raise
                except:
                    log.debug("%s setup failed", sys.exc_info())
                    result.addError(case, sys.exc_info())
                else:
                    to_teardown.append(case)
                    if case.factory:
                        ancestors=case.factory.context.get(case, [])
                        for an in ancestors[:2]:
                            #log.debug('reset ancestor %s', an)
                            if getattr(an, '_multiprocess_shared_', False):
                                an._multiprocess_can_split_=True
                            #an._multiprocess_shared_=False
                    self.collect(case, testQueue, tasks, to_teardown, result)

            else:
                test_addr = self.addtask(testQueue,tasks,case)
                log.debug("Queued test %s (%s) to %s",
                          len(tasks), test_addr, testQueue)
    def run(self, test):
        """
        Execute the test (which may be a test suite). If the test is a suite,
        distribute it out among as many processes as have been configured, at
        as fine a level as is possible given the context fixtures defined in
        the suite or any sub-suites.

        """
        log.debug("%s.run(%s) (%s)", self, test, os.getpid())
        wrapper = self.config.plugins.prepareTest(test)
        if wrapper is not None:
            test = wrapper

        # plugins can decorate or capture the output stream
        wrapped = self.config.plugins.setOutputStream(self.stream)
        if wrapped is not None:
            self.stream = wrapped

        testQueue = Queue()
        resultQueue = Queue()
        tasks = []
        completed = []
        workers = []
        to_teardown = []
        shouldStop = Event()

        result = self._makeResult()
        start = time.time()

        # dispatch and collect results
        # put indexes only on queue because tests aren't picklable
        for case in self.nextBatch(test):
            log.debug("Next batch %s (%s)", case, type(case))
            if isinstance(case, nose.case.Test) and isinstance(case.test, failure.Failure):
                log.debug("Case is a Failure")
                case(result)  # run here to capture the failure
                continue
            # handle shared fixtures
            if isinstance(case, ContextSuite) and case.context is failure.Failure:
                log.debug("Case is a Failure")
                case(result)  # run here to capture the failure
                continue
            elif isinstance(case, ContextSuite) and self.sharedFixtures(case):
                log.debug("%s has shared fixtures", case)
                try:
                    case.setUp()
                except (KeyboardInterrupt, SystemExit):
                    raise
                except:
                    log.debug("%s setup failed", sys.exc_info())
                    result.addError(case, sys.exc_info())
                else:
                    to_teardown.append(case)
                    for _t in case:
                        test_addr = self.addtask(testQueue, tasks, _t)
                        log.debug("Queued shared-fixture test %s (%s) to %s", len(tasks), test_addr, testQueue)
            else:
                test_addr = self.addtask(testQueue, tasks, case)
                log.debug("Queued test %s (%s) to %s", len(tasks), test_addr, testQueue)

        log.debug("Starting %s workers", self.config.multiprocess_workers)
        for i in range(self.config.multiprocess_workers):
            currentaddr = Array("c", 1000)
            currentaddr.value = bytes_("")
            currentstart = Value("d")
            keyboardCaught = Event()
            p = Process(
                target=runner,
                args=(
                    i,
                    testQueue,
                    resultQueue,
                    currentaddr,
                    currentstart,
                    keyboardCaught,
                    shouldStop,
                    self.loaderClass,
                    result.__class__,
                    pickle.dumps(self.config),
                ),
            )
            p.currentaddr = currentaddr
            p.currentstart = currentstart
            p.keyboardCaught = keyboardCaught
            # p.setDaemon(True)
            p.start()
            workers.append(p)
            log.debug("Started worker process %s", i + 1)

        total_tasks = len(tasks)
        # need to keep track of the next time to check for timeouts in case
        # more than one process times out at the same time.
        nexttimeout = self.config.multiprocess_timeout
        while tasks:
            log.debug("Waiting for results (%s/%s tasks), next timeout=%.3fs", len(completed), total_tasks, nexttimeout)
            try:
                iworker, addr, newtask_addrs, batch_result = resultQueue.get(timeout=nexttimeout)
                log.debug("Results received for worker %d, %s, new tasks: %d", iworker, addr, len(newtask_addrs))
                try:
                    try:
                        tasks.remove(addr)
                    except ValueError:
                        log.warn("worker %s failed to remove from tasks: %s", iworker, addr)
                    total_tasks += len(newtask_addrs)
                    for newaddr in newtask_addrs:
                        tasks.append(newaddr)
                except KeyError:
                    log.debug("Got result for unknown task? %s", addr)
                    log.debug("current: %s", str(list(tasks)[0]))
                else:
                    completed.append([addr, batch_result])
                self.consolidate(result, batch_result)
                if self.config.stopOnError and not result.wasSuccessful():
                    # set the stop condition
                    shouldStop.set()
                    break
                if self.config.multiprocess_restartworker:
                    log.debug("joining worker %s", iworker)
                    # wait for working, but not that important if worker
                    # cannot be joined in fact, for workers that add to
                    # testQueue, they will not terminate until all their
                    # items are read
                    workers[iworker].join(timeout=1)
                    if not shouldStop.is_set() and not testQueue.empty():
                        log.debug("starting new process on worker %s", iworker)
                        currentaddr = Array("c", 1000)
                        currentaddr.value = bytes_("")
                        currentstart = Value("d")
                        currentstart.value = time.time()
                        keyboardCaught = Event()
                        workers[iworker] = Process(
                            target=runner,
                            args=(
                                iworker,
                                testQueue,
                                resultQueue,
                                currentaddr,
                                currentstart,
                                keyboardCaught,
                                shouldStop,
                                self.loaderClass,
                                result.__class__,
                                pickle.dumps(self.config),
                            ),
                        )
                        workers[iworker].currentaddr = currentaddr
                        workers[iworker].currentstart = currentstart
                        workers[iworker].keyboardCaught = keyboardCaught
                        workers[iworker].start()
            except Empty:
                log.debug(
                    "Timed out with %s tasks pending " "(empty testQueue=%d): %s",
                    len(tasks),
                    testQueue.empty(),
                    str(tasks),
                )
                any_alive = False
                for iworker, w in enumerate(workers):
                    if w.is_alive():
                        worker_addr = bytes_(w.currentaddr.value, "ascii")
                        timeprocessing = time.time() - w.currentstart.value
                        if len(worker_addr) == 0 and timeprocessing > self.config.multiprocess_timeout - 0.1:
                            log.debug(
                                "worker %d has finished its work item, " "but is not exiting? do we wait for it?",
                                iworker,
                            )
                            if timeprocessing > self.config.multiprocess_timeout + 30:
                                log.error("worker %d force kill", iworker)
                                os.kill(w.pid, signal.SIGINT)
                                time.sleep(0.1)
                        else:
                            any_alive = True
                        if len(worker_addr) > 0 and timeprocessing > self.config.multiprocess_timeout - 0.1:
                            log.debug("timed out worker %s: %s", iworker, worker_addr)
                            w.currentaddr.value = bytes_("")
                            # If the process is in C++ code, sending a SIGINT
                            # might not send a python KeybordInterrupt exception
                            # therefore, send multiple signals until an
                            # exception is caught. If this takes too long, then
                            # terminate the process
                            w.keyboardCaught.clear()
                            startkilltime = time.time()
                            while not w.keyboardCaught.is_set() and w.is_alive():
                                if time.time() - startkilltime > self.waitkilltime:
                                    # have to terminate...
                                    log.error("terminating worker %s", iworker)
                                    w.terminate()
                                    currentaddr = Array("c", 1000)
                                    currentaddr.value = bytes_("")
                                    currentstart = Value("d")
                                    currentstart.value = time.time()
                                    keyboardCaught = Event()
                                    workers[iworker] = Process(
                                        target=runner,
                                        args=(
                                            iworker,
                                            testQueue,
                                            resultQueue,
                                            currentaddr,
                                            currentstart,
                                            keyboardCaught,
                                            shouldStop,
                                            self.loaderClass,
                                            result.__class__,
                                            pickle.dumps(self.config),
                                        ),
                                    )
                                    workers[iworker].currentaddr = currentaddr
                                    workers[iworker].currentstart = currentstart
                                    workers[iworker].keyboardCaught = keyboardCaught
                                    workers[iworker].start()
                                    # there is a small probability that the
                                    # terminated process might send a result,
                                    # which has to be specially handled or
                                    # else processes might get orphaned.
                                    w = workers[iworker]
                                    break
                                os.kill(w.pid, signal.SIGINT)
                                time.sleep(0.1)
                if not any_alive and testQueue.empty():
                    log.debug("All workers dead")
                    break
            nexttimeout = self.config.multiprocess_timeout
            for w in workers:
                if w.is_alive() and len(w.currentaddr.value) > 0:
                    timeprocessing = time.time() - w.currentstart.value
                    if timeprocessing <= self.config.multiprocess_timeout:
                        nexttimeout = min(nexttimeout, self.config.multiprocess_timeout - timeprocessing)

        log.debug("Completed %s tasks (%s remain)", len(completed), len(tasks))

        for case in to_teardown:
            log.debug("Tearing down shared fixtures for %s", case)
            try:
                case.tearDown()
            except (KeyboardInterrupt, SystemExit):
                raise
            except:
                result.addError(case, sys.exc_info())

        stop = time.time()

        # first write since can freeze on shutting down processes
        result.printErrors()
        result.printSummary(start, stop)
        self.config.plugins.finalize(result)

        log.debug("Tell all workers to stop")
        for w in workers:
            if w.is_alive():
                testQueue.put("STOP", block=False)

        # wait for the workers to end
        try:
            for iworker, worker in enumerate(workers):
                if worker.is_alive():
                    log.debug("joining worker %s", iworker)
                    worker.join()  # 10)
                    if worker.is_alive():
                        log.debug("failed to join worker %s", iworker)
        except KeyboardInterrupt:
            log.info("parent received ctrl-c")
            for worker in workers:
                worker.terminate()
                worker.join()

        return result
    def run(self, test):
        """
        Execute the test (which may be a test suite). If the test is a suite,
        distribute it out among as many processes as have been configured, at
        as fine a level as is possible given the context fixtures defined in the
        suite or any sub-suites.

        """
        log.debug("%s.run(%s) (%s)", self, test, os.getpid())
        wrapper = self.config.plugins.prepareTest(test)
        if wrapper is not None:
            test = wrapper

        # plugins can decorate or capture the output stream
        wrapped = self.config.plugins.setOutputStream(self.stream)
        if wrapped is not None:
            self.stream = wrapped

        testQueue = Queue()
        resultQueue = Queue()
        tasks = {}
        completed = {}
        workers = []
        to_teardown = []
        shouldStop = Event()

        result = self._makeResult()
        start = time.time()

        # dispatch and collect results
        # put indexes only on queue because tests aren't picklable
        for case in self.nextBatch(test):
            log.debug("Next batch %s (%s)", case, type(case))
            if (isinstance(case, nose.case.Test) and
                isinstance(case.test, failure.Failure)):
                log.debug("Case is a Failure")
                case(result) # run here to capture the failure
                continue
            # handle shared fixtures
            if isinstance(case, ContextSuite) and self.sharedFixtures(case):
                log.debug("%s has shared fixtures", case)
                try:
                    case.setUp()
                except (KeyboardInterrupt, SystemExit):
                    raise
                except:
                    log.debug("%s setup failed", sys.exc_info())
                    result.addError(case, sys.exc_info())
                else:
                    to_teardown.append(case)
                    for _t in case:
                        test_addr = self.address(_t)
                        testQueue.put(test_addr, block=False)
                        tasks[test_addr] = None
                        log.debug("Queued shared-fixture test %s (%s) to %s",
                                  len(tasks), test_addr, testQueue)

            else:
                test_addr = self.address(case)
                testQueue.put(test_addr, block=False)
                tasks[test_addr] = None
                log.debug("Queued test %s (%s) to %s",
                          len(tasks), test_addr, testQueue)

        log.debug("Starting %s workers", self.config.multiprocess_workers)
        for i in range(self.config.multiprocess_workers):
            p = Process(target=runner, args=(i,
                                             testQueue,
                                             resultQueue,
                                             shouldStop,
                                             self.loaderClass,
                                             result.__class__,
                                             pickle.dumps(self.config)))
            # p.setDaemon(True)
            p.start()
            workers.append(p)
            log.debug("Started worker process %s", i+1)

        num_tasks = len(tasks)
        while tasks:
            log.debug("Waiting for results (%s/%s tasks)",
                      len(completed), num_tasks)
            try:
                addr, batch_result = resultQueue.get(
                    timeout=self.config.multiprocess_timeout)
                log.debug('Results received for %s', addr)
                try:
                    tasks.pop(addr)
                except KeyError:
                    log.debug("Got result for unknown task? %s", addr)
                else:
                    completed[addr] = batch_result
                self.consolidate(result, batch_result)
                if (self.config.stopOnError
                    and not result.wasSuccessful()):
                    # set the stop condition
                    shouldStop.set()
                    break
            except Empty:
                log.debug("Timed out with %s tasks pending", len(tasks))
                any_alive = False
                for w in workers:
                    if w.is_alive():
                        any_alive = True
                        break
                if not any_alive:
                    log.debug("All workers dead")
                    break
        log.debug("Completed %s/%s tasks (%s remain)",
                  len(completed), num_tasks, len(tasks))

        for case in to_teardown:
            log.debug("Tearing down shared fixtures for %s", case)
            try:
                case.tearDown()
            except (KeyboardInterrupt, SystemExit):
                raise
            except:
                result.addError(case, sys.exc_info())

        stop = time.time()

        result.printErrors()
        result.printSummary(start, stop)
        self.config.plugins.finalize(result)

        # Tell all workers to stop
        for w in workers:
            if w.is_alive():
                testQueue.put('STOP', block=False)

        return result