diff --git a/Lib/test/test_copy.py b/Lib/test/test_copy.py
new file mode 100644
index 000000000..45a692022
--- /dev/null
+++ b/Lib/test/test_copy.py
@@ -0,0 +1,888 @@
+"""Unit tests for the copy module."""
+
+import copy
+import copyreg
+import weakref
+import abc
+from operator import le, lt, ge, gt, eq, ne
+
+import unittest
+
+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)
+
+    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 Classic:
+            pass
+        class NewStyle(object):
+            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, Classic, max, WithMetaclass]
+        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)
+
+    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 Classic:
+            pass
+        class NewStyle(object):
+            pass
+        def f():
+            pass
+        tests = [None, 42, 2**100, 3.14, True, False, 1j,
+                 "hello", "hello\u1234", f.__code__,
+                 NewStyle, Classic, max]
+        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)
+
+    def test_deepcopy_range(self):
+        class I(int):
+            pass
+        x = range(I(10))
+        y = copy.deepcopy(x)
+        self.assertIsNot(y, x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y.stop, x.stop)
+        self.assertEqual(y.stop, x.stop)
+        self.assertIsInstance(y.stop, I)
+
+    # _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_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
+        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
+        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
+        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()
+
+
+def global_foo(x, y): return x+y
+
+if __name__ == "__main__":
+    unittest.main()