import itertools
import unittest


hash_values = [3, 2, 5, 6, 5, 1, 0, 3, 4, 2, 0, 1, 3, 2, 3, 4, 7, 7, 7, 2, 0, 1, 4, 6, 0, 3, 3, 1, 3, 2, 0, 7, 7, 7, 2]
hash_i = 0


class Thread2:
    __slots__ = ('hashvalue',)

    def __init__(self):
        global hash_i
        self.hashvalue = hash_values[hash_i % len(hash_values)]
        hash_i += 1

    def __hash__(self):
        return self.hashvalue


main_thread = Thread2()
items = [Thread2() for i in range(10)]

dangling = set()


class LeakTest(unittest.TestCase):
    counter = itertools.count()

    def test_leak(self):
        item = items[next(self.counter) % len(items)]
        dangling.add(main_thread)
        dangling.add(item)
        dangling.discard(item)
        dangling.discard(main_thread)
        assert len(dangling) == 0