diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py index 54de508a832..ade39fb7587 100644 --- a/Lib/test/test_set.py +++ b/Lib/test/test_set.py @@ -10,6 +10,8 @@ import sys import warnings import collections import collections.abc +import itertools +import string class PassThru(Exception): pass @@ -711,6 +713,28 @@ class TestFrozenSet(TestJointOps, unittest.TestCase): addhashvalue(hash(frozenset([e for e, m in elemmasks if m&i]))) self.assertEqual(len(hashvalues), 2**n) + def letter_range(n): + return string.ascii_letters[:n] + + def zf_range(n): + # https://en.wikipedia.org/wiki/Set-theoretic_definition_of_natural_numbers + nums = [frozenset()] + for i in range(n-1): + num = frozenset(nums) + nums.append(num) + return nums[:n] + + def powerset(s): + for i in range(len(s)+1): + yield from map(frozenset, itertools.combinations(s, i)) + + for n in range(18): + t = 2 ** n + mask = t - 1 + for nums in (range, letter_range, zf_range): + u = len({h & mask for h in map(hash, powerset(nums(n)))}) + self.assertGreater(4*u, t) + class FrozenSetSubclass(frozenset): pass