cpython/Lib/test/test_copy.py

"""Unit tests for the copy module."""

import copy
import copyreg
import weakref
import abc
from operator import le, lt, ge, gt, eq, ne, attrgetter

import unittest
from test import support

order_comparisons = le, lt, ge, gt
equality_comparisons = eq, ne
comparisons = order_comparisons + equality_comparisons

class TestCopy(unittest.TestCase):

    # Attempt full line coverage of copy.py from top to bottom

    def test_exceptions(self):
        self.assertIs(copy.Error, copy.error)
        self.assertTrue(issubclass(copy.Error, Exception))

    # The copy() method

    def test_copy_basic(self):
        x = 42
        y = copy.copy(x)
        self.assertEqual(x, y)

    def test_copy_copy(self):
        class C(object):
            def __init__(self, foo):
                self.foo = foo
            def __copy__(self):
                return C(self.foo)
        x = C(42)
        y = copy.copy(x)
        self.assertEqual(y.__class__, x.__class__)
        self.assertEqual(y.foo, x.foo)

    def test_copy_registry(self):
        class C(object):
            def __new__(cls, foo):
                obj = object.__new__(cls)
                obj.foo = foo
                return obj
        def pickle_C(obj):
            return (C, (obj.foo,))
        x = C(42)
        self.assertRaises(TypeError, copy.copy, x)
        copyreg.pickle(C, pickle_C, C)
        y = copy.copy(x)
        self.assertIsNot(x, y)
        self.assertEqual(type(y), C)
        self.assertEqual(y.foo, x.foo)

    def test_copy_reduce_ex(self):
        class C(object):
            def __reduce_ex__(self, proto):
                c.append(1)
                return ""
            def __reduce__(self):
                self.fail("shouldn't call this")
        c = []
        x = C()
        y = copy.copy(x)
        self.assertIs(y, x)
        self.assertEqual(c, [1])

    def test_copy_reduce(self):
        class C(object):
            def __reduce__(self):
                c.append(1)
                return ""
        c = []
        x = C()
        y = copy.copy(x)
        self.assertIs(y, x)
        self.assertEqual(c, [1])

    def test_copy_cant(self):
        class C(object):
            def __getattribute__(self, name):
                if name.startswith("__reduce"):
                    raise AttributeError(name)
                return object.__getattribute__(self, name)
        x = C()
        self.assertRaises(copy.Error, copy.copy, x)

    # Type-specific _copy_xxx() methods

    def test_copy_atomic(self):
        class NewStyle:
            pass
        def f():
            pass
        class WithMetaclass(metaclass=abc.ABCMeta):
            pass
        tests = [None, ..., NotImplemented,
                 42, 2**100, 3.14, True, False, 1j,
                 "hello", "hello\u1234", f.__code__,
                 b"world", bytes(range(256)), range(10), slice(1, 10, 2),
                 NewStyle, max, WithMetaclass, property()]
        for x in tests:
            self.assertIs(copy.copy(x), x)

    def test_copy_list(self):
        x = [1, 2, 3]
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        x = []
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)

    def test_copy_tuple(self):
        x = (1, 2, 3)
        self.assertIs(copy.copy(x), x)
        x = ()
        self.assertIs(copy.copy(x), x)
        x = (1, 2, 3, [])
        self.assertIs(copy.copy(x), x)

    def test_copy_dict(self):
        x = {"foo": 1, "bar": 2}
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        x = {}
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)

    def test_copy_set(self):
        x = {1, 2, 3}
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        x = set()
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)

    def test_copy_frozenset(self):
        x = frozenset({1, 2, 3})
        self.assertIs(copy.copy(x), x)
        x = frozenset()
        self.assertIs(copy.copy(x), x)

    def test_copy_bytearray(self):
        x = bytearray(b'abc')
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        x = bytearray()
        y = copy.copy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)

    def test_copy_inst_vanilla(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        self.assertEqual(copy.copy(x), x)

    def test_copy_inst_copy(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __copy__(self):
                return C(self.foo)
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        self.assertEqual(copy.copy(x), x)

    def test_copy_inst_getinitargs(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getinitargs__(self):
                return (self.foo,)
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        self.assertEqual(copy.copy(x), x)

    def test_copy_inst_getnewargs(self):
        class C(int):
            def __new__(cls, foo):
                self = int.__new__(cls)
                self.foo = foo
                return self
            def __getnewargs__(self):
                return self.foo,
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        y = copy.copy(x)
        self.assertIsInstance(y, C)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertEqual(y.foo, x.foo)

    def test_copy_inst_getnewargs_ex(self):
        class C(int):
            def __new__(cls, *, foo):
                self = int.__new__(cls)
                self.foo = foo
                return self
            def __getnewargs_ex__(self):
                return (), {'foo': self.foo}
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(foo=42)
        y = copy.copy(x)
        self.assertIsInstance(y, C)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertEqual(y.foo, x.foo)

    def test_copy_inst_getstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getstate__(self):
                return {"foo": self.foo}
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        self.assertEqual(copy.copy(x), x)

    def test_copy_inst_setstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __setstate__(self, state):
                self.foo = state["foo"]
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        self.assertEqual(copy.copy(x), x)

    def test_copy_inst_getstate_setstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getstate__(self):
                return self.foo
            def __setstate__(self, state):
                self.foo = state
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(42)
        self.assertEqual(copy.copy(x), x)
        # State with boolean value is false (issue #25718)
        x = C(0.0)
        self.assertEqual(copy.copy(x), x)

    # The deepcopy() method

    def test_deepcopy_basic(self):
        x = 42
        y = copy.deepcopy(x)
        self.assertEqual(y, x)

    def test_deepcopy_memo(self):
        # Tests of reflexive objects are under type-specific sections below.
        # This tests only repetitions of objects.
        x = []
        x = [x, x]
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y[0], x[0])
        self.assertIs(y[0], y[1])

    def test_deepcopy_issubclass(self):
        # XXX Note: there's no way to test the TypeError coming out of
        # issubclass() -- this can only happen when an extension
        # module defines a "type" that doesn't formally inherit from
        # type.
        class Meta(type):
            pass
        class C(metaclass=Meta):
            pass
        self.assertEqual(copy.deepcopy(C), C)

    def test_deepcopy_deepcopy(self):
        class C(object):
            def __init__(self, foo):
                self.foo = foo
            def __deepcopy__(self, memo=None):
                return C(self.foo)
        x = C(42)
        y = copy.deepcopy(x)
        self.assertEqual(y.__class__, x.__class__)
        self.assertEqual(y.foo, x.foo)

    def test_deepcopy_registry(self):
        class C(object):
            def __new__(cls, foo):
                obj = object.__new__(cls)
                obj.foo = foo
                return obj
        def pickle_C(obj):
            return (C, (obj.foo,))
        x = C(42)
        self.assertRaises(TypeError, copy.deepcopy, x)
        copyreg.pickle(C, pickle_C, C)
        y = copy.deepcopy(x)
        self.assertIsNot(x, y)
        self.assertEqual(type(y), C)
        self.assertEqual(y.foo, x.foo)

    def test_deepcopy_reduce_ex(self):
        class C(object):
            def __reduce_ex__(self, proto):
                c.append(1)
                return ""
            def __reduce__(self):
                self.fail("shouldn't call this")
        c = []
        x = C()
        y = copy.deepcopy(x)
        self.assertIs(y, x)
        self.assertEqual(c, [1])

    def test_deepcopy_reduce(self):
        class C(object):
            def __reduce__(self):
                c.append(1)
                return ""
        c = []
        x = C()
        y = copy.deepcopy(x)
        self.assertIs(y, x)
        self.assertEqual(c, [1])

    def test_deepcopy_cant(self):
        class C(object):
            def __getattribute__(self, name):
                if name.startswith("__reduce"):
                    raise AttributeError(name)
                return object.__getattribute__(self, name)
        x = C()
        self.assertRaises(copy.Error, copy.deepcopy, x)

    # Type-specific _deepcopy_xxx() methods

    def test_deepcopy_atomic(self):
        class NewStyle:
            pass
        def f():
            pass
        tests = [None, ..., NotImplemented, 42, 2**100, 3.14, True, False, 1j,
                 b"bytes", "hello", "hello\u1234", f.__code__,
                 NewStyle, range(10), max, property()]
        for x in tests:
            self.assertIs(copy.deepcopy(x), x)

    def test_deepcopy_list(self):
        x = [[1, 2], 3]
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(x, y)
        self.assertIsNot(x[0], y[0])

    def test_deepcopy_reflexive_list(self):
        x = []
        x.append(x)
        y = copy.deepcopy(x)
        for op in comparisons:
            self.assertRaises(RecursionError, op, y, x)
        self.assertIsNot(y, x)
        self.assertIs(y[0], y)
        self.assertEqual(len(y), 1)

    def test_deepcopy_empty_tuple(self):
        x = ()
        y = copy.deepcopy(x)
        self.assertIs(x, y)

    def test_deepcopy_tuple(self):
        x = ([1, 2], 3)
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(x, y)
        self.assertIsNot(x[0], y[0])

    def test_deepcopy_tuple_of_immutables(self):
        x = ((1, 2), 3)
        y = copy.deepcopy(x)
        self.assertIs(x, y)

    def test_deepcopy_reflexive_tuple(self):
        x = ([],)
        x[0].append(x)
        y = copy.deepcopy(x)
        for op in comparisons:
            self.assertRaises(RecursionError, op, y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y[0], x[0])
        self.assertIs(y[0][0], y)

    def test_deepcopy_dict(self):
        x = {"foo": [1, 2], "bar": 3}
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(x, y)
        self.assertIsNot(x["foo"], y["foo"])

    def test_deepcopy_reflexive_dict(self):
        x = {}
        x['foo'] = x
        y = copy.deepcopy(x)
        for op in order_comparisons:
            self.assertRaises(TypeError, op, y, x)
        for op in equality_comparisons:
            self.assertRaises(RecursionError, op, y, x)
        self.assertIsNot(y, x)
        self.assertIs(y['foo'], y)
        self.assertEqual(len(y), 1)

    def test_deepcopy_keepalive(self):
        memo = {}
        x = []
        y = copy.deepcopy(x, memo)
        self.assertIs(memo[id(memo)][0], x)

    def test_deepcopy_dont_memo_immutable(self):
        memo = {}
        x = [1, 2, 3, 4]
        y = copy.deepcopy(x, memo)
        self.assertEqual(y, x)
        # There's the entry for the new list, and the keep alive.
        self.assertEqual(len(memo), 2)

        memo = {}
        x = [(1, 2)]
        y = copy.deepcopy(x, memo)
        self.assertEqual(y, x)
        # Tuples with immutable contents are immutable for deepcopy.
        self.assertEqual(len(memo), 2)

    def test_deepcopy_inst_vanilla(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_deepcopy(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __deepcopy__(self, memo):
                return C(copy.deepcopy(self.foo, memo))
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_getinitargs(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getinitargs__(self):
                return (self.foo,)
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_getnewargs(self):
        class C(int):
            def __new__(cls, foo):
                self = int.__new__(cls)
                self.foo = foo
                return self
            def __getnewargs__(self):
                return self.foo,
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertIsInstance(y, C)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertEqual(y.foo, x.foo)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_getnewargs_ex(self):
        class C(int):
            def __new__(cls, *, foo):
                self = int.__new__(cls)
                self.foo = foo
                return self
            def __getnewargs_ex__(self):
                return (), {'foo': self.foo}
            def __eq__(self, other):
                return self.foo == other.foo
        x = C(foo=[42])
        y = copy.deepcopy(x)
        self.assertIsInstance(y, C)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertEqual(y.foo, x.foo)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_getstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getstate__(self):
                return {"foo": self.foo}
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_setstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __setstate__(self, state):
                self.foo = state["foo"]
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_inst_getstate_setstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getstate__(self):
                return self.foo
            def __setstate__(self, state):
                self.foo = state
            def __eq__(self, other):
                return self.foo == other.foo
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y.foo, x.foo)
        # State with boolean value is false (issue #25718)
        x = C([])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_deepcopy_reflexive_inst(self):
        class C:
            pass
        x = C()
        x.foo = x
        y = copy.deepcopy(x)
        self.assertIsNot(y, x)
        self.assertIs(y.foo, y)

    # _reconstruct()

    def test_reconstruct_string(self):
        class C(object):
            def __reduce__(self):
                return ""
        x = C()
        y = copy.copy(x)
        self.assertIs(y, x)
        y = copy.deepcopy(x)
        self.assertIs(y, x)

    def test_reconstruct_nostate(self):
        class C(object):
            def __reduce__(self):
                return (C, ())
        x = C()
        x.foo = 42
        y = copy.copy(x)
        self.assertIs(y.__class__, x.__class__)
        y = copy.deepcopy(x)
        self.assertIs(y.__class__, x.__class__)

    def test_reconstruct_state(self):
        class C(object):
            def __reduce__(self):
                return (C, (), self.__dict__)
            def __eq__(self, other):
                return self.__dict__ == other.__dict__
        x = C()
        x.foo = [42]
        y = copy.copy(x)
        self.assertEqual(y, x)
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_reconstruct_state_setstate(self):
        class C(object):
            def __reduce__(self):
                return (C, (), self.__dict__)
            def __setstate__(self, state):
                self.__dict__.update(state)
            def __eq__(self, other):
                return self.__dict__ == other.__dict__
        x = C()
        x.foo = [42]
        y = copy.copy(x)
        self.assertEqual(y, x)
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assertIsNot(y.foo, x.foo)

    def test_reconstruct_reflexive(self):
        class C(object):
            pass
        x = C()
        x.foo = x
        y = copy.deepcopy(x)
        self.assertIsNot(y, x)
        self.assertIs(y.foo, y)

    # Additions for Python 2.3 and pickle protocol 2

    def test_reduce_4tuple(self):
        class C(list):
            def __reduce__(self):
                return (C, (), self.__dict__, iter(self))
            def __eq__(self, other):
                return (list(self) == list(other) and
                        self.__dict__ == other.__dict__)
        x = C([[1, 2], 3])
        y = copy.copy(x)
        self.assertEqual(x, y)
        self.assertIsNot(x, y)
        self.assertIs(x[0], y[0])
        y = copy.deepcopy(x)
        self.assertEqual(x, y)
        self.assertIsNot(x, y)
        self.assertIsNot(x[0], y[0])

    def test_reduce_5tuple(self):
        class C(dict):
            def __reduce__(self):
                return (C, (), self.__dict__, None, self.items())
            def __eq__(self, other):
                return (dict(self) == dict(other) and
                        self.__dict__ == other.__dict__)
        x = C([("foo", [1, 2]), ("bar", 3)])
        y = copy.copy(x)
        self.assertEqual(x, y)
        self.assertIsNot(x, y)
        self.assertIs(x["foo"], y["foo"])
        y = copy.deepcopy(x)
        self.assertEqual(x, y)
        self.assertIsNot(x, y)
        self.assertIsNot(x["foo"], y["foo"])

    def test_reduce_6tuple(self):
        def state_setter(*args, **kwargs):
            self.fail("shouldn't call this")
        class C:
            def __reduce__(self):
                return C, (), self.__dict__, None, None, state_setter
        x = C()
        with self.assertRaises(TypeError):
            copy.copy(x)
        with self.assertRaises(TypeError):
            copy.deepcopy(x)

    def test_reduce_6tuple_none(self):
        class C:
            def __reduce__(self):
                return C, (), self.__dict__, None, None, None
        x = C()
        with self.assertRaises(TypeError):
            copy.copy(x)
        with self.assertRaises(TypeError):
            copy.deepcopy(x)

    def test_copy_slots(self):
        class C(object):
            __slots__ = ["foo"]
        x = C()
        x.foo = [42]
        y = copy.copy(x)
        self.assertIs(x.foo, y.foo)

    def test_deepcopy_slots(self):
        class C(object):
            __slots__ = ["foo"]
        x = C()
        x.foo = [42]
        y = copy.deepcopy(x)
        self.assertEqual(x.foo, y.foo)
        self.assertIsNot(x.foo, y.foo)

    def test_deepcopy_dict_subclass(self):
        class C(dict):
            def __init__(self, d=None):
                if not d:
                    d = {}
                self._keys = list(d.keys())
                super().__init__(d)
            def __setitem__(self, key, item):
                super().__setitem__(key, item)
                if key not in self._keys:
                    self._keys.append(key)
        x = C(d={'foo':0})
        y = copy.deepcopy(x)
        self.assertEqual(x, y)
        self.assertEqual(x._keys, y._keys)
        self.assertIsNot(x, y)
        x['bar'] = 1
        self.assertNotEqual(x, y)
        self.assertNotEqual(x._keys, y._keys)

    def test_copy_list_subclass(self):
        class C(list):
            pass
        x = C([[1, 2], 3])
        x.foo = [4, 5]
        y = copy.copy(x)
        self.assertEqual(list(x), list(y))
        self.assertEqual(x.foo, y.foo)
        self.assertIs(x[0], y[0])
        self.assertIs(x.foo, y.foo)

    def test_deepcopy_list_subclass(self):
        class C(list):
            pass
        x = C([[1, 2], 3])
        x.foo = [4, 5]
        y = copy.deepcopy(x)
        self.assertEqual(list(x), list(y))
        self.assertEqual(x.foo, y.foo)
        self.assertIsNot(x[0], y[0])
        self.assertIsNot(x.foo, y.foo)

    def test_copy_tuple_subclass(self):
        class C(tuple):
            pass
        x = C([1, 2, 3])
        self.assertEqual(tuple(x), (1, 2, 3))
        y = copy.copy(x)
        self.assertEqual(tuple(y), (1, 2, 3))

    def test_deepcopy_tuple_subclass(self):
        class C(tuple):
            pass
        x = C([[1, 2], 3])
        self.assertEqual(tuple(x), ([1, 2], 3))
        y = copy.deepcopy(x)
        self.assertEqual(tuple(y), ([1, 2], 3))
        self.assertIsNot(x, y)
        self.assertIsNot(x[0], y[0])

    def test_getstate_exc(self):
        class EvilState(object):
            def __getstate__(self):
                raise ValueError("ain't got no stickin' state")
        self.assertRaises(ValueError, copy.copy, EvilState())

    def test_copy_function(self):
        self.assertEqual(copy.copy(global_foo), global_foo)
        def foo(x, y): return x+y
        self.assertEqual(copy.copy(foo), foo)
        bar = lambda: None
        self.assertEqual(copy.copy(bar), bar)

    def test_deepcopy_function(self):
        self.assertEqual(copy.deepcopy(global_foo), global_foo)
        def foo(x, y): return x+y
        self.assertEqual(copy.deepcopy(foo), foo)
        bar = lambda: None
        self.assertEqual(copy.deepcopy(bar), bar)

    def _check_weakref(self, _copy):
        class C(object):
            pass
        obj = C()
        x = weakref.ref(obj)
        y = _copy(x)
        self.assertIs(y, x)
        del obj
        y = _copy(x)
        self.assertIs(y, x)

    def test_copy_weakref(self):
        self._check_weakref(copy.copy)

    def test_deepcopy_weakref(self):
        self._check_weakref(copy.deepcopy)

    def _check_copy_weakdict(self, _dicttype):
        class C(object):
            pass
        a, b, c, d = [C() for i in range(4)]
        u = _dicttype()
        u[a] = b
        u[c] = d
        v = copy.copy(u)
        self.assertIsNot(v, u)
        self.assertEqual(v, u)
        self.assertEqual(v[a], b)
        self.assertEqual(v[c], d)
        self.assertEqual(len(v), 2)
        del c, d
        support.gc_collect()  # For PyPy or other GCs.
        self.assertEqual(len(v), 1)
        x, y = C(), C()
        # The underlying containers are decoupled
        v[x] = y
        self.assertNotIn(x, u)

    def test_copy_weakkeydict(self):
        self._check_copy_weakdict(weakref.WeakKeyDictionary)

    def test_copy_weakvaluedict(self):
        self._check_copy_weakdict(weakref.WeakValueDictionary)

    def test_deepcopy_weakkeydict(self):
        class C(object):
            def __init__(self, i):
                self.i = i
        a, b, c, d = [C(i) for i in range(4)]
        u = weakref.WeakKeyDictionary()
        u[a] = b
        u[c] = d
        # Keys aren't copied, values are
        v = copy.deepcopy(u)
        self.assertNotEqual(v, u)
        self.assertEqual(len(v), 2)
        self.assertIsNot(v[a], b)
        self.assertIsNot(v[c], d)
        self.assertEqual(v[a].i, b.i)
        self.assertEqual(v[c].i, d.i)
        del c
        support.gc_collect()  # For PyPy or other GCs.
        self.assertEqual(len(v), 1)

    def test_deepcopy_weakvaluedict(self):
        class C(object):
            def __init__(self, i):
                self.i = i
        a, b, c, d = [C(i) for i in range(4)]
        u = weakref.WeakValueDictionary()
        u[a] = b
        u[c] = d
        # Keys are copied, values aren't
        v = copy.deepcopy(u)
        self.assertNotEqual(v, u)
        self.assertEqual(len(v), 2)
        (x, y), (z, t) = sorted(v.items(), key=lambda pair: pair[0].i)
        self.assertIsNot(x, a)
        self.assertEqual(x.i, a.i)
        self.assertIs(y, b)
        self.assertIsNot(z, c)
        self.assertEqual(z.i, c.i)
        self.assertIs(t, d)
        del x, y, z, t
        del d
        support.gc_collect()  # For PyPy or other GCs.
        self.assertEqual(len(v), 1)

    def test_deepcopy_bound_method(self):
        class Foo(object):
            def m(self):
                pass
        f = Foo()
        f.b = f.m
        g = copy.deepcopy(f)
        self.assertEqual(g.m, g.b)
        self.assertIs(g.b.__self__, g)
        g.b()


class TestReplace(unittest.TestCase):

    def test_unsupported(self):
        self.assertRaises(TypeError, copy.replace, 1)
        self.assertRaises(TypeError, copy.replace, [])
        self.assertRaises(TypeError, copy.replace, {})
        def f(): pass
        self.assertRaises(TypeError, copy.replace, f)
        class A: pass
        self.assertRaises(TypeError, copy.replace, A)
        self.assertRaises(TypeError, copy.replace, A())

    def test_replace_method(self):
        class A:
            def __new__(cls, x, y=0):
                self = object.__new__(cls)
                self.x = x
                self.y = y
                return self

            def __init__(self, *args, **kwargs):
                self.z = self.x + self.y

            def __replace__(self, **changes):
                x = changes.get('x', self.x)
                y = changes.get('y', self.y)
                return type(self)(x, y)

        attrs = attrgetter('x', 'y', 'z')
        a = A(11, 22)
        self.assertEqual(attrs(copy.replace(a)), (11, 22, 33))
        self.assertEqual(attrs(copy.replace(a, x=1)), (1, 22, 23))
        self.assertEqual(attrs(copy.replace(a, y=2)), (11, 2, 13))
        self.assertEqual(attrs(copy.replace(a, x=1, y=2)), (1, 2, 3))

    def test_namedtuple(self):
        from collections import namedtuple
        from typing import NamedTuple
        PointFromCall = namedtuple('Point', 'x y', defaults=(0,))
        class PointFromInheritance(PointFromCall):
            pass
        class PointFromClass(NamedTuple):
            x: int
            y: int = 0
        for Point in (PointFromCall, PointFromInheritance, PointFromClass):
            with self.subTest(Point=Point):
                p = Point(11, 22)
                self.assertIsInstance(p, Point)
                self.assertEqual(copy.replace(p), (11, 22))
                self.assertIsInstance(copy.replace(p), Point)
                self.assertEqual(copy.replace(p, x=1), (1, 22))
                self.assertEqual(copy.replace(p, y=2), (11, 2))
                self.assertEqual(copy.replace(p, x=1, y=2), (1, 2))
                with self.assertRaisesRegex(ValueError, 'unexpected field name'):
                    copy.replace(p, x=1, error=2)

    def test_dataclass(self):
        from dataclasses import dataclass
        @dataclass
        class C:
            x: int
            y: int = 0

        attrs = attrgetter('x', 'y')
        c = C(11, 22)
        self.assertEqual(attrs(copy.replace(c)), (11, 22))
        self.assertEqual(attrs(copy.replace(c, x=1)), (1, 22))
        self.assertEqual(attrs(copy.replace(c, y=2)), (11, 2))
        self.assertEqual(attrs(copy.replace(c, x=1, y=2)), (1, 2))
        with self.assertRaisesRegex(TypeError, 'unexpected keyword argument'):
            copy.replace(c, x=1, error=2)


def global_foo(x, y): return x+y


if __name__ == "__main__":
    unittest.main()