def run(self, result):
        """
        Distribute test cases across workers.

        Return an identifier of each test case with its result in order to use
        imap_unordered to show results as soon as they're available.

        To minimize pickling errors when getting results from workers:

        - pass back numeric indexes in self.subsuites instead of tests
        - make tracebacks picklable with tblib, if available

        Even with tblib, errors may still occur for dynamically created
        exception classes such Model.DoesNotExist which cannot be unpickled.
        """
        if tblib is not None:
            tblib.pickling_support.install()

        counter = multiprocessing.Value(ctypes.c_int, 0)
        pool = multiprocessing.Pool(
            processes=self.processes,
            initializer=self.init_worker.__func__,
            initargs=[counter])
        args = [
            (index, subsuite, self.failfast)
            for index, subsuite in enumerate(self.subsuites)
        ]
        test_results = pool.imap_unordered(self.run_subsuite.__func__, args)

        while True:
            if result.shouldStop:
                pool.terminate()
                break

            try:
                subsuite_index, events = test_results.next(timeout=0.1)
            except multiprocessing.TimeoutError:
                continue
            except __HOLE__:
                pool.close()
                break

            tests = list(self.subsuites[subsuite_index])
            for event in events:
                event_name = event[0]
                handler = getattr(result, event_name, None)
                if handler is None:
                    continue
                test = tests[event[1]]
                args = event[2:]
                handler(test, *args)

        pool.join()

        return result
dataset/ETHPy150Open django/django/django/test/runner.py/ParallelTestSuite.run