test_backports.py

# -*- coding: utf-8 -*-
"""
Tests for various backported functions and classes in ``future.backports``
"""

from __future__ import absolute_import, print_function

import sys
import copy
import inspect
import pickle
from random import randrange, shuffle

from future.backports.misc import (count,
                                   _count,
                                   OrderedDict,
                                   Counter,
                                   ChainMap,
                                   _count_elements)
from future.utils import PY2, PY26
from future.tests.base import unittest, skip26, expectedFailurePY27

if PY2:
    from collections import Mapping, MutableMapping
else:
    from collections.abc import Mapping, MutableMapping


class CountTest(unittest.TestCase):
    """Test the count function."""

    def _test_count_func(self, func):
        self.assertEqual(next(func(1)), 1)
        self.assertEqual(next(func(start=1)), 1)

        c = func()
        self.assertEqual(next(c), 0)
        self.assertEqual(next(c), 1)
        self.assertEqual(next(c), 2)
        c = func(1, 1)
        self.assertEqual(next(c), 1)
        self.assertEqual(next(c), 2)
        c = func(step=1)
        self.assertEqual(next(c), 0)
        self.assertEqual(next(c), 1)
        c = func(start=1, step=1)
        self.assertEqual(next(c), 1)
        self.assertEqual(next(c), 2)

        c = func(-1)
        self.assertEqual(next(c), -1)
        self.assertEqual(next(c), 0)
        self.assertEqual(next(c), 1)
        c = func(1, -1)
        self.assertEqual(next(c), 1)
        self.assertEqual(next(c), 0)
        self.assertEqual(next(c), -1)
        c = func(-1, -1)
        self.assertEqual(next(c), -1)
        self.assertEqual(next(c), -2)
        self.assertEqual(next(c), -3)

    def test_count(self):
        """Test the count function."""
        self._test_count_func(count)

    def test_own_count(self):
        """Test own count implementation."""
        if PY26:
            self.assertIs(count, _count)
        else:
            self.assertNotEqual(count, _count)
            self._test_count_func(_count)


################################################################################
### ChainMap (helper class for configparser and the string module)
################################################################################

class TestChainMap(unittest.TestCase):

    def test_basics(self):
        c = ChainMap()
        c['a'] = 1
        c['b'] = 2
        d = c.new_child()
        d['b'] = 20
        d['c'] = 30
        self.assertEqual(d.maps, [{'b':20, 'c':30}, {'a':1, 'b':2}])  # check internal state
        self.assertEqual(sorted(d.items()),
                         sorted(dict(a=1, b=20, c=30).items()))       # check items/iter/getitem
        self.assertEqual(len(d), 3)                                   # check len
        for key in 'abc':                                             # check contains
            self.assertIn(key, d)
        for k, v in dict(a=1, b=20, c=30, z=100).items():             # check get
            self.assertEqual(d.get(k, 100), v)

        del d['b']                                                    # unmask a value
        self.assertEqual(d.maps, [{'c':30}, {'a':1, 'b':2}])          # check internal state
        self.assertEqual(sorted(d.items()),
                         sorted(dict(a=1, b=2, c=30).items()))        # check items/iter/getitem
        self.assertEqual(len(d), 3)                                   # check len
        for key in 'abc':                                             # check contains
            self.assertIn(key, d)
        for k, v in dict(a=1, b=2, c=30, z=100).items():              # check get
            self.assertEqual(d.get(k, 100), v)
        self.assertIn(repr(d), [                                      # check repr
            type(d).__name__ + "({'c': 30}, {'a': 1, 'b': 2})",
            type(d).__name__ + "({'c': 30}, {'b': 2, 'a': 1})"
        ])

        for e in d.copy(), copy.copy(d):                               # check shallow copies
            self.assertEqual(d, e)
            self.assertEqual(d.maps, e.maps)
            self.assertIsNot(d, e)
            self.assertIsNot(d.maps[0], e.maps[0])
            for m1, m2 in zip(d.maps[1:], e.maps[1:]):
                self.assertIs(m1, m2)

        _ChainMap = ChainMap

        for e in [pickle.loads(pickle.dumps(d)),
                  copy.deepcopy(d),
                  eval(repr(d))
                ]:                                                    # check deep copies
            self.assertEqual(d, e)
            self.assertEqual(d.maps, e.maps)
            self.assertIsNot(d, e)
            for m1, m2 in zip(d.maps, e.maps):
                self.assertIsNot(m1, m2, e)

        f = d.new_child()
        f['b'] = 5
        self.assertEqual(f.maps, [{'b': 5}, {'c':30}, {'a':1, 'b':2}])
        self.assertEqual(f.parents.maps, [{'c':30}, {'a':1, 'b':2}])   # check parents
        self.assertEqual(f['b'], 5)                                    # find first in chain
        self.assertEqual(f.parents['b'], 2)                            # look beyond maps[0]

    def test_contructor(self):
        self.assertEqual(ChainMap().maps, [{}])                        # no-args --> one new dict
        self.assertEqual(ChainMap({1:2}).maps, [{1:2}])                # 1 arg --> list

    def test_bool(self):
        self.assertFalse(ChainMap())
        self.assertFalse(ChainMap({}, {}))
        self.assertTrue(ChainMap({1:2}, {}))
        self.assertTrue(ChainMap({}, {1:2}))

    def test_missing(self):
        class DefaultChainMap(ChainMap):
            def __missing__(self, key):
                return 999
        d = DefaultChainMap(dict(a=1, b=2), dict(b=20, c=30))
        for k, v in dict(a=1, b=2, c=30, d=999).items():
            self.assertEqual(d[k], v)                                  # check __getitem__ w/missing
        for k, v in dict(a=1, b=2, c=30, d=77).items():
            self.assertEqual(d.get(k, 77), v)                          # check get() w/ missing
        for k, v in dict(a=True, b=True, c=True, d=False).items():
            self.assertEqual(k in d, v)                                # check __contains__ w/missing
        self.assertEqual(d.pop('a', 1001), 1, d)
        self.assertEqual(d.pop('a', 1002), 1002)                       # check pop() w/missing
        self.assertEqual(d.popitem(), ('b', 2))                        # check popitem() w/missing
        with self.assertRaises(KeyError):
            d.popitem()

    def test_dict_coercion(self):
        d = ChainMap(dict(a=1, b=2), dict(b=20, c=30))
        self.assertEqual(dict(d), dict(a=1, b=2, c=30))
        self.assertEqual(dict(d.items()), dict(a=1, b=2, c=30))


################################################################################
### Counter
################################################################################

class CounterSubclassWithSetItem(Counter):
    # Test a counter subclass that overrides __setitem__
    def __init__(self, *args, **kwds):
        self.called = False
        Counter.__init__(self, *args, **kwds)
    def __setitem__(self, key, value):
        self.called = True
        Counter.__setitem__(self, key, value)

class CounterSubclassWithGet(Counter):
    # Test a counter subclass that overrides get()
    def __init__(self, *args, **kwds):
        self.called = False
        Counter.__init__(self, *args, **kwds)
    def get(self, key, default):
        self.called = True
        return Counter.get(self, key, default)

class TestCounter(unittest.TestCase):

    def test_basics(self):
        c = Counter('abcaba')
        self.assertEqual(c, Counter({'a':3 , 'b': 2, 'c': 1}))
        self.assertEqual(c, Counter(a=3, b=2, c=1))
        self.assertIsInstance(c, dict)
        self.assertIsInstance(c, Mapping)
        self.assertTrue(issubclass(Counter, dict))
        self.assertTrue(issubclass(Counter, Mapping))
        self.assertEqual(len(c), 3)
        self.assertEqual(sum(c.values()), 6)
        self.assertEqual(sorted(c.values()), [1, 2, 3])
        self.assertEqual(sorted(c.keys()), ['a', 'b', 'c'])
        self.assertEqual(sorted(c), ['a', 'b', 'c'])
        self.assertEqual(sorted(c.items()),
                         [('a', 3), ('b', 2), ('c', 1)])
        self.assertEqual(c['b'], 2)
        self.assertEqual(c['z'], 0)
        self.assertEqual(c.__contains__('c'), True)
        self.assertEqual(c.__contains__('z'), False)
        self.assertEqual(c.get('b', 10), 2)
        self.assertEqual(c.get('z', 10), 10)
        self.assertEqual(c, dict(a=3, b=2, c=1))
        self.assertEqual(repr(c), "Counter({'a': 3, 'b': 2, 'c': 1})")
        self.assertEqual(c.most_common(), [('a', 3), ('b', 2), ('c', 1)])
        for i in range(5):
            self.assertEqual(c.most_common(i),
                             [('a', 3), ('b', 2), ('c', 1)][:i])
        self.assertEqual(''.join(sorted(c.elements())), 'aaabbc')
        c['a'] += 1         # increment an existing value
        c['b'] -= 2         # sub existing value to zero
        del c['c']          # remove an entry
        del c['c']          # make sure that del doesn't raise KeyError
        c['d'] -= 2         # sub from a missing value
        c['e'] = -5         # directly assign a missing value
        c['f'] += 4         # add to a missing value
        self.assertEqual(c, dict(a=4, b=0, d=-2, e=-5, f=4))
        self.assertEqual(''.join(sorted(c.elements())), 'aaaaffff')
        self.assertEqual(c.pop('f'), 4)
        self.assertNotIn('f', c)
        for i in range(3):
            elem, cnt = c.popitem()
            self.assertNotIn(elem, c)
        c.clear()
        self.assertEqual(c, {})
        self.assertEqual(repr(c), 'Counter()')
        self.assertRaises(NotImplementedError, Counter.fromkeys, 'abc')
        self.assertRaises(TypeError, hash, c)
        c.update(dict(a=5, b=3))
        c.update(c=1)
        c.update(Counter('a' * 50 + 'b' * 30))
        c.update()          # test case with no args
        c.__init__('a' * 500 + 'b' * 300)
        c.__init__('cdc')
        c.__init__()
        self.assertEqual(c, dict(a=555, b=333, c=3, d=1))
        self.assertEqual(c.setdefault('d', 5), 1)
        self.assertEqual(c['d'], 1)
        self.assertEqual(c.setdefault('e', 5), 5)
        self.assertEqual(c['e'], 5)

    def test_copying(self):
        # Check that counters are copyable, deepcopyable, picklable, and
        #have a repr/eval round-trip
        words = Counter('which witch had which witches wrist watch'.split())
        update_test = Counter()
        update_test.update(words)
        for i, dup in enumerate([
                    words.copy(),
                    copy.copy(words),
                    copy.deepcopy(words),
                    pickle.loads(pickle.dumps(words, 0)),
                    pickle.loads(pickle.dumps(words, 1)),
                    pickle.loads(pickle.dumps(words, 2)),
                    pickle.loads(pickle.dumps(words, -1)),
                    eval(repr(words)),
                    update_test,
                    Counter(words),
                    ]):
            msg = (i, dup, words)
            self.assertTrue(dup is not words)
            self.assertEqual(dup, words)
            self.assertEqual(len(dup), len(words))
            self.assertEqual(type(dup), type(words))

    def test_copy_subclass(self):
        class MyCounter(Counter):
            pass
        c = MyCounter('slartibartfast')
        d = c.copy()
        self.assertEqual(d, c)
        self.assertEqual(len(d), len(c))
        self.assertEqual(type(d), type(c))

    def test_conversions(self):
        # Convert to: set, list, dict
        s = 'she sells sea shells by the sea shore'
        self.assertEqual(sorted(Counter(s).elements()), sorted(s))
        self.assertEqual(sorted(Counter(s)), sorted(set(s)))
        self.assertEqual(dict(Counter(s)), dict(Counter(s).items()))
        self.assertEqual(set(Counter(s)), set(s))

    def test_invariant_for_the_in_operator(self):
        c = Counter(a=10, b=-2, c=0)
        for elem in c:
            self.assertTrue(elem in c)
            self.assertIn(elem, c)

    def test_multiset_operations(self):
        # Verify that adding a zero counter will strip zeros and negatives
        c = Counter(a=10, b=-2, c=0) + Counter()
        self.assertEqual(dict(c), dict(a=10))

        elements = 'abcd'
        for i in range(1000):
            # test random pairs of multisets
            p = Counter(dict((elem, randrange(-2,4)) for elem in elements))
            p.update(e=1, f=-1, g=0)
            q = Counter(dict((elem, randrange(-2,4)) for elem in elements))
            q.update(h=1, i=-1, j=0)
            for counterop, numberop in [
                (Counter.__add__, lambda x, y: max(0, x+y)),
                (Counter.__sub__, lambda x, y: max(0, x-y)),
                (Counter.__or__, lambda x, y: max(0,x,y)),
                (Counter.__and__, lambda x, y: max(0, min(x,y))),
            ]:
                result = counterop(p, q)
                for x in elements:
                    self.assertEqual(numberop(p[x], q[x]), result[x],
                                     (counterop, x, p, q))
                # verify that results exclude non-positive counts
                self.assertTrue(x>0 for x in result.values())

        elements = 'abcdef'
        for i in range(100):
            # verify that random multisets with no repeats are exactly like sets
            p = Counter(dict((elem, randrange(0, 2)) for elem in elements))
            q = Counter(dict((elem, randrange(0, 2)) for elem in elements))
            for counterop, setop in [
                (Counter.__sub__, set.__sub__),
                (Counter.__or__, set.__or__),
                (Counter.__and__, set.__and__),
            ]:
                counter_result = counterop(p, q)
                set_result = setop(set(p.elements()), set(q.elements()))
                self.assertEqual(counter_result, dict.fromkeys(set_result, 1))

    @expectedFailurePY27
    def test_inplace_operations(self):
        elements = 'abcd'
        for i in range(1000):
            # test random pairs of multisets
            p = Counter(dict((elem, randrange(-2,4)) for elem in elements))
            p.update(e=1, f=-1, g=0)
            q = Counter(dict((elem, randrange(-2,4)) for elem in elements))
            q.update(h=1, i=-1, j=0)
            for inplace_op, regular_op in [
                (Counter.__iadd__, Counter.__add__),
                (Counter.__isub__, Counter.__sub__),
                (Counter.__ior__, Counter.__or__),
                (Counter.__iand__, Counter.__and__),
            ]:
                c = p.copy()
                c_id = id(c)
                regular_result = regular_op(c, q)
                inplace_result = inplace_op(c, q)
                self.assertEqual(inplace_result, regular_result)
                self.assertEqual(id(inplace_result), c_id)

    def test_subtract(self):
        c = Counter(a=-5, b=0, c=5, d=10, e=15,g=40)
        c.subtract(a=1, b=2, c=-3, d=10, e=20, f=30, h=-50)
        self.assertEqual(c, Counter(a=-6, b=-2, c=8, d=0, e=-5, f=-30, g=40, h=50))
        c = Counter(a=-5, b=0, c=5, d=10, e=15,g=40)
        c.subtract(Counter(a=1, b=2, c=-3, d=10, e=20, f=30, h=-50))
        self.assertEqual(c, Counter(a=-6, b=-2, c=8, d=0, e=-5, f=-30, g=40, h=50))
        c = Counter('aaabbcd')
        c.subtract('aaaabbcce')
        self.assertEqual(c, Counter(a=-1, b=0, c=-1, d=1, e=-1))

    @expectedFailurePY27
    def test_unary(self):
        c = Counter(a=-5, b=0, c=5, d=10, e=15,g=40)
        self.assertEqual(dict(+c), dict(c=5, d=10, e=15, g=40))
        self.assertEqual(dict(-c), dict(a=5))

    def test_repr_nonsortable(self):
        c = Counter(a=2, b=None)
        r = repr(c)
        self.assertIn("'a': 2", r)
        self.assertIn("'b': None", r)

    def test_helper_function(self):
        # two paths, one for real dicts and one for other mappings
        elems = list('abracadabra')

        d = dict()
        _count_elements(d, elems)
        self.assertEqual(d, {'a': 5, 'r': 2, 'b': 2, 'c': 1, 'd': 1})

        m = OrderedDict()
        _count_elements(m, elems)
        self.assertEqual(m,
             OrderedDict([('a', 5), ('b', 2), ('r', 2), ('c', 1), ('d', 1)]))

        # test fidelity to the pure python version
        c = CounterSubclassWithSetItem('abracadabra')
        self.assertTrue(c.called)
        c = CounterSubclassWithGet('abracadabra')
        self.assertTrue(c.called)


################################################################################
### OrderedDict
################################################################################

class TestOrderedDict(unittest.TestCase):

    def test_init(self):
        with self.assertRaises(TypeError):
            OrderedDict([('a', 1), ('b', 2)], None)                                 # too many args
        pairs = [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)]
        self.assertEqual(sorted(OrderedDict(dict(pairs)).items()), pairs)           # dict input
        self.assertEqual(sorted(OrderedDict(**dict(pairs)).items()), pairs)         # kwds input
        self.assertEqual(list(OrderedDict(pairs).items()), pairs)                   # pairs input
        self.assertEqual(list(OrderedDict([('a', 1), ('b', 2), ('c', 9), ('d', 4)],
                                          c=3, e=5).items()), pairs)                # mixed input

        # Make sure that direct calls to __init__ do not clear previous contents
        d = OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 44), ('e', 55)])
        d.__init__([('e', 5), ('f', 6)], g=7, d=4)
        self.assertEqual(list(d.items()),
            [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5), ('f', 6), ('g', 7)])

    def test_update(self):
        with self.assertRaises(TypeError):
            OrderedDict().update([('a', 1), ('b', 2)], None)                        # too many args
        pairs = [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)]
        od = OrderedDict()
        od.update(dict(pairs))
        self.assertEqual(sorted(od.items()), pairs)                                 # dict input
        od = OrderedDict()
        od.update(**dict(pairs))
        self.assertEqual(sorted(od.items()), pairs)                                 # kwds input
        od = OrderedDict()
        od.update(pairs)
        self.assertEqual(list(od.items()), pairs)                                   # pairs input
        od = OrderedDict()
        od.update([('a', 1), ('b', 2), ('c', 9), ('d', 4)], c=3, e=5)
        self.assertEqual(list(od.items()), pairs)                                   # mixed input

        ### The tests below fail on Py2.6
        if PY26:
            return
        # Issue 9137: Named argument called 'other' or 'self'
        # shouldn't be treated specially.
        od = OrderedDict()
        od.update(self=23)
        self.assertEqual(list(od.items()), [('self', 23)])
        od = OrderedDict()
        od.update(other={})
        self.assertEqual(list(od.items()), [('other', {})])
        od = OrderedDict()
        od.update(red=5, blue=6, other=7, self=8)
        self.assertEqual(sorted(list(od.items())),
                         [('blue', 6), ('other', 7), ('red', 5), ('self', 8)])

        # Make sure that direct calls to update do not clear previous contents
        # add that updates items are not moved to the end
        d = OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 44), ('e', 55)])
        d.update([('e', 5), ('f', 6)], g=7, d=4)
        self.assertEqual(list(d.items()),
            [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5), ('f', 6), ('g', 7)])

    def test_abc(self):
        self.assertIsInstance(OrderedDict(), MutableMapping)
        self.assertTrue(issubclass(OrderedDict, MutableMapping))

    def test_clear(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        shuffle(pairs)
        od = OrderedDict(pairs)
        self.assertEqual(len(od), len(pairs))
        od.clear()
        self.assertEqual(len(od), 0)

    def test_delitem(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        od = OrderedDict(pairs)
        del od['a']
        self.assertNotIn('a', od)
        with self.assertRaises(KeyError):
            del od['a']
        self.assertEqual(list(od.items()), pairs[:2] + pairs[3:])

    def test_setitem(self):
        od = OrderedDict([('d', 1), ('b', 2), ('c', 3), ('a', 4), ('e', 5)])
        od['c'] = 10           # existing element
        od['f'] = 20           # new element
        self.assertEqual(list(od.items()),
                         [('d', 1), ('b', 2), ('c', 10), ('a', 4), ('e', 5), ('f', 20)])

    def test_iterators(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        shuffle(pairs)
        od = OrderedDict(pairs)
        self.assertEqual(list(od), [t[0] for t in pairs])
        self.assertEqual(list(od.keys()), [t[0] for t in pairs])
        self.assertEqual(list(od.values()), [t[1] for t in pairs])
        self.assertEqual(list(od.items()), pairs)
        self.assertEqual(list(reversed(od)),
                         [t[0] for t in reversed(pairs)])

    def test_popitem(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        shuffle(pairs)
        od = OrderedDict(pairs)
        while pairs:
            self.assertEqual(od.popitem(), pairs.pop())
        with self.assertRaises(KeyError):
            od.popitem()
        self.assertEqual(len(od), 0)

    def test_pop(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        shuffle(pairs)
        od = OrderedDict(pairs)
        shuffle(pairs)
        while pairs:
            k, v = pairs.pop()
            self.assertEqual(od.pop(k), v)
        with self.assertRaises(KeyError):
            od.pop('xyz')
        self.assertEqual(len(od), 0)
        self.assertEqual(od.pop(k, 12345), 12345)

        # make sure pop still works when __missing__ is defined
        class Missing(OrderedDict):
            def __missing__(self, key):
                return 0
        m = Missing(a=1)
        self.assertEqual(m.pop('b', 5), 5)
        self.assertEqual(m.pop('a', 6), 1)
        self.assertEqual(m.pop('a', 6), 6)
        with self.assertRaises(KeyError):
            m.pop('a')

    def test_equality(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        shuffle(pairs)
        od1 = OrderedDict(pairs)
        od2 = OrderedDict(pairs)
        self.assertEqual(od1, od2)          # same order implies equality
        pairs = pairs[2:] + pairs[:2]
        od2 = OrderedDict(pairs)
        self.assertNotEqual(od1, od2)       # different order implies inequality
        # comparison to regular dict is not order sensitive
        self.assertEqual(od1, dict(od2))
        self.assertEqual(dict(od2), od1)
        # different length implied inequality
        self.assertNotEqual(od1, OrderedDict(pairs[:-1]))

    def test_copying(self):
        # Check that ordered dicts are copyable, deepcopyable, picklable,
        # and have a repr/eval round-trip
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        od = OrderedDict(pairs)
        update_test = OrderedDict()
        update_test.update(od)
        for i, dup in enumerate([
                    od.copy(),
                    copy.copy(od),
                    copy.deepcopy(od),
                    pickle.loads(pickle.dumps(od, 0)),
                    pickle.loads(pickle.dumps(od, 1)),
                    pickle.loads(pickle.dumps(od, 2)),
                    # pickle.loads(pickle.dumps(od, 3)),
                    pickle.loads(pickle.dumps(od, -1)),
                    eval(repr(od)),
                    update_test,
                    OrderedDict(od),
                    ]):
            self.assertTrue(dup is not od)
            self.assertEqual(dup, od)
            self.assertEqual(list(dup.items()), list(od.items()))
            self.assertEqual(len(dup), len(od))
            self.assertEqual(type(dup), type(od))

    def test_yaml_linkage(self):
        # Verify that __reduce__ is setup in a way that supports PyYAML's dump() feature.
        # In yaml, lists are native but tuples are not.
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        od = OrderedDict(pairs)
        # yaml.dump(od) -->
        # '!!python/object/apply:__main__.OrderedDict\n- - [a, 1]\n  - [b, 2]\n'
        self.assertTrue(all(type(pair)==list for pair in od.__reduce__()[1]))

    # def test_reduce_not_too_fat(self):
    #     # do not save instance dictionary if not needed
    #     pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
    #     od = OrderedDict(pairs)
    #     self.assertEqual(len(od.__reduce__()), 2)
    #     od.x = 10
    #     self.assertEqual(len(od.__reduce__()), 3)

    def test_repr(self):
        od = OrderedDict([('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)])
        self.assertEqual(repr(od),
            "OrderedDict([('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)])")
        self.assertEqual(eval(repr(od)), od)
        self.assertEqual(repr(OrderedDict()), "OrderedDict()")

    def test_repr_recursive(self):
        # See issue #9826
        od = OrderedDict.fromkeys('abc')
        od['x'] = od
        self.assertEqual(repr(od),
            "OrderedDict([('a', None), ('b', None), ('c', None), ('x', ...)])")

    def test_setdefault(self):
        pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
        shuffle(pairs)
        od = OrderedDict(pairs)
        pair_order = list(od.items())
        self.assertEqual(od.setdefault('a', 10), 3)
        # make sure order didn't change
        self.assertEqual(list(od.items()), pair_order)
        self.assertEqual(od.setdefault('x', 10), 10)
        # make sure 'x' is added to the end
        self.assertEqual(list(od.items())[-1], ('x', 10))

        # make sure setdefault still works when __missing__ is defined
        class Missing(OrderedDict):
            def __missing__(self, key):
                return 0
        self.assertEqual(Missing().setdefault(5, 9), 9)

    def test_reinsert(self):
        # Given insert a, insert b, delete a, re-insert a,
        # verify that a is now later than b.
        od = OrderedDict()
        od['a'] = 1
        od['b'] = 2
        del od['a']
        od['a'] = 1
        self.assertEqual(list(od.items()), [('b', 2), ('a', 1)])

    @expectedFailurePY27
    def test_move_to_end(self):
        od = OrderedDict.fromkeys('abcde')
        self.assertEqual(list(od), list('abcde'))
        od.move_to_end('c')
        self.assertEqual(list(od), list('abdec'))
        od.move_to_end('c', 0)
        self.assertEqual(list(od), list('cabde'))
        od.move_to_end('c', 0)
        self.assertEqual(list(od), list('cabde'))
        od.move_to_end('e')
        self.assertEqual(list(od), list('cabde'))
        with self.assertRaises(KeyError):
            od.move_to_end('x')

    def test_override_update(self):
        # Verify that subclasses can override update() without breaking __init__()
        class MyOD(OrderedDict):
            def update(self, *args, **kwds):
                raise Exception()
        items = [('a', 1), ('c', 3), ('b', 2)]
        self.assertEqual(list(MyOD(items).items()), items)


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