Lib/test/test_copy.py

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

import sys
import copy

import unittest
from test import test_support

class TestCopy(unittest.TestCase):

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

    def test_exceptions(self):
        self.assert_(copy.Error is copy.error)
        self.assert_(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_reduce(self):
        class C(object):
            def __reduce__(self):
                return ""
        x = C()
        y = copy.copy(x)
        self.assert_(y is x)

    def test_copy_cant(self):
        class C(object):
            def __getattribute__(self, name):
                if name == "__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
        tests = [None, 42, 2L**100, 3.14, True, False, 1j,
                 "hello", u"hello\u1234", f.func_code,
                 NewStyle, xrange(10), Classic]
        for x in tests:
            self.assert_(copy.copy(x) is x, `x`)

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

    def test_copy_tuple(self):
        x = (1, 2, 3)
        self.assertEqual(copy.copy(x), x)

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

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

    def test_copy_inst_getstate(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getstate__(self):
                return {"foo": self.foo}
            def __cmp__(self, other):
                return cmp(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 __cmp__(self, other):
                return cmp(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 __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C(42)
        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):
        x = []
        x.append(x)
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y is not x)
        self.assert_(y[0] is not x[0])
        self.assert_(y is y[0])

    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
        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_reduce(self):
        class C(object):
            def __reduce__(self):
                return ""
        x = C()
        y = copy.deepcopy(x)
        self.assert_(y is x)

    def test_deepcopy_cant(self):
        class C(object):
            def __getattribute__(self, name):
                if name == "__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, 2L**100, 3.14, True, False, 1j,
                 "hello", u"hello\u1234", f.func_code,
                 NewStyle, xrange(10)]
        for x in tests:
            self.assert_(copy.deepcopy(x) is x, `x`)

    def test_deepcopy_list(self):
        x = [[1, 2], 3]
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(x is not y)
        self.assert_(x[0] is not y[0])

    def test_deepcopy_tuple(self):
        x = ([1, 2], 3)
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(x is not y)
        self.assert_(x[0] is not y[0])

    def test_deepcopy_dict(self):
        x = {"foo": [1, 2], "bar": 3}
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(x is not y)
        self.assert_(x["foo"] is not y["foo"])

    def test_deepcopy_keepalive(self):
        memo = {}
        x = 42
        y = copy.deepcopy(x, memo)
        self.assert_(memo[id(x)] is x)

    def test_deepcopy_inst_vanilla(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y.foo is not 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 __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y is not x)
        self.assert_(y.foo is not x.foo)

    def test_deepcopy_inst_getinitargs(self):
        class C:
            def __init__(self, foo):
                self.foo = foo
            def __getinitargs__(self):
                return (self.foo,)
            def __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y is not x)
        self.assert_(y.foo is not 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 __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y is not x)
        self.assert_(y.foo is not 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 __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y is not x)
        self.assert_(y.foo is not 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 __cmp__(self, other):
                return cmp(self.foo, other.foo)
        x = C([42])
        y = copy.deepcopy(x)
        self.assertEqual(y, x)
        self.assert_(y is not x)
        self.assert_(y.foo is not x.foo)

    # _reconstruct()

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

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

    def test_reconstruct_state(self):
        class C(object):
            def __reduce__(self):
                return (C, (), self.__dict__)
            def __cmp__(self, other):
                return cmp(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.assert_(y.foo is not 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 __cmp__(self, other):
                return cmp(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.assert_(y.foo is not x.foo)

def test_main():
    suite = unittest.TestSuite()
    suite.addTest(unittest.makeSuite(TestCopy))
    test_support.run_suite(suite)

if __name__ == "__main__":
    test_main()