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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
import unittest
import dns.immutable
import dns._immutable_ctx
class ImmutableTestCase(unittest.TestCase):
def test_immutable_dict_hash(self):
d1 = dns.immutable.Dict({"a": 1, "b": 2})
d2 = dns.immutable.Dict({"b": 2, "a": 1})
d3 = {"b": 2, "a": 1}
self.assertEqual(d1, d2)
self.assertEqual(d2, d3)
self.assertEqual(hash(d1), hash(d2))
def test_immutable_dict_hash_cache(self):
d = dns.immutable.Dict({"a": 1, "b": 2})
self.assertEqual(d._hash, None)
h1 = hash(d)
self.assertEqual(d._hash, h1)
h2 = hash(d)
self.assertEqual(h1, h2)
def test_constify(self):
items = (
(bytearray([1, 2, 3]), b"\x01\x02\x03"),
((1, 2, 3), (1, 2, 3)),
((1, [2], 3), (1, (2,), 3)),
([1, 2, 3], (1, 2, 3)),
([1, {"a": [1, 2]}], (1, dns.immutable.Dict({"a": (1, 2)}))),
("hi", "hi"),
(b"hi", b"hi"),
)
for input, expected in items:
self.assertEqual(dns.immutable.constify(input), expected)
self.assertIsInstance(dns.immutable.constify({"a": 1}), dns.immutable.Dict)
class DecoratorTestCase(unittest.TestCase):
immutable_module = dns._immutable_ctx
def make_classes(self):
class A:
def __init__(self, a, akw=10):
self.a = a
self.akw = akw
class B(A):
def __init__(self, a, b):
super().__init__(a, akw=20)
self.b = b
B = self.immutable_module.immutable(B)
# note C is immutable by inheritance
class C(B):
def __init__(self, a, b, c):
super().__init__(a, b)
self.c = c
C = self.immutable_module.immutable(C)
class SA:
__slots__ = ("a", "akw")
def __init__(self, a, akw=10):
self.a = a
self.akw = akw
class SB(A):
__slots__ = "b"
def __init__(self, a, b):
super().__init__(a, akw=20)
self.b = b
SB = self.immutable_module.immutable(SB)
# note SC is immutable by inheritance and has no slots of its own
class SC(SB):
def __init__(self, a, b, c):
super().__init__(a, b)
self.c = c
SC = self.immutable_module.immutable(SC)
return ((A, B, C), (SA, SB, SC))
def test_basic(self):
for A, B, C in self.make_classes():
a = A(1)
self.assertEqual(a.a, 1)
self.assertEqual(a.akw, 10)
b = B(11, 21)
self.assertEqual(b.a, 11)
self.assertEqual(b.akw, 20)
self.assertEqual(b.b, 21)
c = C(111, 211, 311)
self.assertEqual(c.a, 111)
self.assertEqual(c.akw, 20)
self.assertEqual(c.b, 211)
self.assertEqual(c.c, 311)
# changing A is ok!
a.a = 11
self.assertEqual(a.a, 11)
# changing B is not!
with self.assertRaises(TypeError):
b.a = 11
with self.assertRaises(TypeError):
del b.a
def test_constructor_deletes_attribute(self):
class A:
def __init__(self, a):
self.a = a
self.b = a
del self.b
A = self.immutable_module.immutable(A)
a = A(10)
self.assertEqual(a.a, 10)
self.assertFalse(hasattr(a, "b"))
def test_no_collateral_damage(self):
# A and B are immutable but not related. The magic that lets
# us write to immutable things while initializing B should not let
# B mess with A.
class A:
def __init__(self, a):
self.a = a
A = self.immutable_module.immutable(A)
class B:
def __init__(self, a, b):
self.b = a.a + b
# rudely attempt to mutate innocent immutable bystander 'a'
a.a = 1000
B = self.immutable_module.immutable(B)
a = A(10)
self.assertEqual(a.a, 10)
with self.assertRaises(TypeError):
B(a, 20)
self.assertEqual(a.a, 10)
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