def test_none_collisions(self):
collisions = [NoneCollision('a', level) for level in range(7)]
indices = [map_mask(none_hash, shift) for shift in range(0, 32, 5)]
for i, c in enumerate(collisions[:-1], 1):
self.assertNotEqual(c, None)
c_hash = map_hash(c)
self.assertNotEqual(c_hash, none_hash)
for j, idx in enumerate(indices[:i]):
self.assertEqual(map_mask(c_hash, j * 5), idx)
for j, idx in enumerate(indices[i:], i):
self.assertNotEqual(map_mask(c_hash, j * 5), idx)
c = collisions[-1]
self.assertNotEqual(c, None)
c_hash = map_hash(c)
self.assertEqual(c_hash, none_hash)
for i, idx in enumerate(indices):
self.assertEqual(map_mask(c_hash, i * 5), idx)
import unittest
from immutables.map import map_hash, map_mask, Map as PyMap
from immutables._testutils import HashKey
none_hash = map_hash(None)
assert (none_hash != 1)
assert ((none_hash >> 32) == 0)
not_collision = 0xffffffff & (~none_hash)
mask = 0x7ffffffff
none_collisions = [
none_hash & (mask >> shift) for shift in reversed(range(0, 32, 5))
]
assert (len(none_collisions) == 7)
none_collisions = [
h | (not_collision & (mask << shift))
for shift, h in zip(range(5, 37, 5), none_collisions)
]
class NoneCollision(HashKey):
def __init__(self, name, level):
if name is None:
raise ValueError("Can't have a NoneCollision with a None value")
super().__init__(none_collisions[level], name)
def __eq__(self, other):
if other is None:
return False