cpython/Lib/test/test_ordered_dict.py

724 lines
26 KiB
Python

import contextlib
import copy
import pickle
from random import randrange, shuffle
import struct
import sys
import unittest
from collections.abc import MutableMapping
from test import mapping_tests, support
py_coll = support.import_fresh_module('collections', blocked=['_collections'])
c_coll = support.import_fresh_module('collections', fresh=['_collections'])
@contextlib.contextmanager
def replaced_module(name, replacement):
original_module = sys.modules[name]
sys.modules[name] = replacement
try:
yield
finally:
sys.modules[name] = original_module
class OrderedDictTests:
def test_init(self):
OrderedDict = self.OrderedDict
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 no positional args conflict with possible kwdargs
self.assertEqual(list(OrderedDict(self=42).items()), [('self', 42)])
self.assertEqual(list(OrderedDict(other=42).items()), [('other', 42)])
self.assertRaises(TypeError, OrderedDict, 42)
self.assertRaises(TypeError, OrderedDict, (), ())
self.assertRaises(TypeError, OrderedDict.__init__)
# 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):
OrderedDict = self.OrderedDict
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
# 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)])
self.assertRaises(TypeError, OrderedDict().update, 42)
self.assertRaises(TypeError, OrderedDict().update, (), ())
self.assertRaises(TypeError, OrderedDict.update)
self.assertRaises(TypeError, OrderedDict().update, 42)
self.assertRaises(TypeError, OrderedDict().update, (), ())
self.assertRaises(TypeError, OrderedDict.update)
def test_fromkeys(self):
OrderedDict = self.OrderedDict
od = OrderedDict.fromkeys('abc')
self.assertEqual(list(od.items()), [(c, None) for c in 'abc'])
od = OrderedDict.fromkeys('abc', value=None)
self.assertEqual(list(od.items()), [(c, None) for c in 'abc'])
od = OrderedDict.fromkeys('abc', value=0)
self.assertEqual(list(od.items()), [(c, 0) for c in 'abc'])
def test_abc(self):
OrderedDict = self.OrderedDict
self.assertIsInstance(OrderedDict(), MutableMapping)
self.assertTrue(issubclass(OrderedDict, MutableMapping))
def test_clear(self):
OrderedDict = self.OrderedDict
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):
OrderedDict = self.OrderedDict
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):
OrderedDict = self.OrderedDict
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):
OrderedDict = self.OrderedDict
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)])
self.assertEqual(list(reversed(od.keys())),
[t[0] for t in reversed(pairs)])
self.assertEqual(list(reversed(od.values())),
[t[1] for t in reversed(pairs)])
self.assertEqual(list(reversed(od.items())), list(reversed(pairs)))
def test_detect_deletion_during_iteration(self):
OrderedDict = self.OrderedDict
od = OrderedDict.fromkeys('abc')
it = iter(od)
key = next(it)
del od[key]
with self.assertRaises(Exception):
# Note, the exact exception raised is not guaranteed
# The only guarantee that the next() will not succeed
next(it)
def test_sorted_iterators(self):
OrderedDict = self.OrderedDict
with self.assertRaises(TypeError):
OrderedDict([('a', 1), ('b', 2)], None)
pairs = [('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)]
od = OrderedDict(pairs)
self.assertEqual(sorted(od), [t[0] for t in pairs])
self.assertEqual(sorted(od.keys()), [t[0] for t in pairs])
self.assertEqual(sorted(od.values()), [t[1] for t in pairs])
self.assertEqual(sorted(od.items()), pairs)
self.assertEqual(sorted(reversed(od)),
sorted([t[0] for t in reversed(pairs)]))
def test_iterators_empty(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
empty = []
self.assertEqual(list(od), empty)
self.assertEqual(list(od.keys()), empty)
self.assertEqual(list(od.values()), empty)
self.assertEqual(list(od.items()), empty)
self.assertEqual(list(reversed(od)), empty)
self.assertEqual(list(reversed(od.keys())), empty)
self.assertEqual(list(reversed(od.values())), empty)
self.assertEqual(list(reversed(od.items())), empty)
def test_popitem(self):
OrderedDict = self.OrderedDict
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_popitem_last(self):
OrderedDict = self.OrderedDict
pairs = [(i, i) for i in range(30)]
obj = OrderedDict(pairs)
for i in range(8):
obj.popitem(True)
obj.popitem(True)
obj.popitem(last=True)
self.assertEqual(len(obj), 20)
def test_pop(self):
OrderedDict = self.OrderedDict
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)
self.assertEqual(m.pop('a', default=6), 6)
with self.assertRaises(KeyError):
m.pop('a')
def test_equality(self):
OrderedDict = self.OrderedDict
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):
OrderedDict = self.OrderedDict
# 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)
def check(dup):
msg = "\ncopy: %s\nod: %s" % (dup, od)
self.assertIsNot(dup, od, msg)
self.assertEqual(dup, od)
self.assertEqual(list(dup.items()), list(od.items()))
self.assertEqual(len(dup), len(od))
self.assertEqual(type(dup), type(od))
check(od.copy())
check(copy.copy(od))
check(copy.deepcopy(od))
# pickle directly pulls the module, so we have to fake it
with replaced_module('collections', self.module):
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
with self.subTest(proto=proto):
check(pickle.loads(pickle.dumps(od, proto)))
check(eval(repr(od)))
update_test = OrderedDict()
update_test.update(od)
check(update_test)
check(OrderedDict(od))
def test_yaml_linkage(self):
OrderedDict = self.OrderedDict
# 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):
OrderedDict = self.OrderedDict
# 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.assertIsNone(od.__reduce__()[2])
od.x = 10
self.assertIsNotNone(od.__reduce__()[2])
def test_pickle_recursive(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
od[1] = od
# pickle directly pulls the module, so we have to fake it
with replaced_module('collections', self.module):
for proto in range(-1, pickle.HIGHEST_PROTOCOL + 1):
dup = pickle.loads(pickle.dumps(od, proto))
self.assertIsNot(dup, od)
self.assertEqual(list(dup.keys()), [1])
self.assertIs(dup[1], dup)
def test_repr(self):
OrderedDict = self.OrderedDict
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):
OrderedDict = self.OrderedDict
# 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):
OrderedDict = self.OrderedDict
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))
self.assertEqual(od.setdefault('g', default=9), 9)
# 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):
OrderedDict = self.OrderedDict
# 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']
self.assertEqual(list(od.items()), [('b', 2)])
od['a'] = 1
self.assertEqual(list(od.items()), [('b', 2), ('a', 1)])
def test_move_to_end(self):
OrderedDict = self.OrderedDict
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'))
od.move_to_end('b', last=False)
self.assertEqual(list(od), list('bcade'))
with self.assertRaises(KeyError):
od.move_to_end('x')
with self.assertRaises(KeyError):
od.move_to_end('x', 0)
def test_move_to_end_issue25406(self):
OrderedDict = self.OrderedDict
od = OrderedDict.fromkeys('abc')
od.move_to_end('c', last=False)
self.assertEqual(list(od), list('cab'))
od.move_to_end('a', last=False)
self.assertEqual(list(od), list('acb'))
od = OrderedDict.fromkeys('abc')
od.move_to_end('a')
self.assertEqual(list(od), list('bca'))
od.move_to_end('c')
self.assertEqual(list(od), list('bac'))
def test_sizeof(self):
OrderedDict = self.OrderedDict
# Wimpy test: Just verify the reported size is larger than a regular dict
d = dict(a=1)
od = OrderedDict(**d)
self.assertGreater(sys.getsizeof(od), sys.getsizeof(d))
def test_views(self):
OrderedDict = self.OrderedDict
# See http://bugs.python.org/issue24286
s = 'the quick brown fox jumped over a lazy dog yesterday before dawn'.split()
od = OrderedDict.fromkeys(s)
self.assertEqual(od.keys(), dict(od).keys())
self.assertEqual(od.items(), dict(od).items())
def test_override_update(self):
OrderedDict = self.OrderedDict
# 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)
def test_highly_nested(self):
# Issue 25395: crashes during garbage collection
OrderedDict = self.OrderedDict
obj = None
for _ in range(1000):
obj = OrderedDict([(None, obj)])
del obj
support.gc_collect()
def test_highly_nested_subclass(self):
# Issue 25395: crashes during garbage collection
OrderedDict = self.OrderedDict
deleted = []
class MyOD(OrderedDict):
def __del__(self):
deleted.append(self.i)
obj = None
for i in range(100):
obj = MyOD([(None, obj)])
obj.i = i
del obj
support.gc_collect()
self.assertEqual(deleted, list(reversed(range(100))))
def test_delitem_hash_collision(self):
OrderedDict = self.OrderedDict
class Key:
def __init__(self, hash):
self._hash = hash
self.value = str(id(self))
def __hash__(self):
return self._hash
def __eq__(self, other):
try:
return self.value == other.value
except AttributeError:
return False
def __repr__(self):
return self.value
def blocking_hash(hash):
# See the collision-handling in lookdict (in Objects/dictobject.c).
MINSIZE = 8
i = (hash & MINSIZE-1)
return (i << 2) + i + hash + 1
COLLIDING = 1
key = Key(COLLIDING)
colliding = Key(COLLIDING)
blocking = Key(blocking_hash(COLLIDING))
od = OrderedDict()
od[key] = ...
od[blocking] = ...
od[colliding] = ...
od['after'] = ...
del od[blocking]
del od[colliding]
self.assertEqual(list(od.items()), [(key, ...), ('after', ...)])
def test_issue24347(self):
OrderedDict = self.OrderedDict
class Key:
def __hash__(self):
return randrange(100000)
od = OrderedDict()
for i in range(100):
key = Key()
od[key] = i
# These should not crash.
with self.assertRaises(KeyError):
list(od.values())
with self.assertRaises(KeyError):
list(od.items())
with self.assertRaises(KeyError):
repr(od)
with self.assertRaises(KeyError):
od.copy()
def test_issue24348(self):
OrderedDict = self.OrderedDict
class Key:
def __hash__(self):
return 1
od = OrderedDict()
od[Key()] = 0
# This should not crash.
od.popitem()
def test_issue24667(self):
"""
dict resizes after a certain number of insertion operations,
whether or not there were deletions that freed up slots in the
hash table. During fast node lookup, OrderedDict must correctly
respond to all resizes, even if the current "size" is the same
as the old one. We verify that here by forcing a dict resize
on a sparse odict and then perform an operation that should
trigger an odict resize (e.g. popitem). One key aspect here is
that we will keep the size of the odict the same at each popitem
call. This verifies that we handled the dict resize properly.
"""
OrderedDict = self.OrderedDict
od = OrderedDict()
for c0 in '0123456789ABCDEF':
for c1 in '0123456789ABCDEF':
if len(od) == 4:
# This should not raise a KeyError.
od.popitem(last=False)
key = c0 + c1
od[key] = key
# Direct use of dict methods
def test_dict_setitem(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
dict.__setitem__(od, 'spam', 1)
self.assertNotIn('NULL', repr(od))
def test_dict_delitem(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
od['spam'] = 1
od['ham'] = 2
dict.__delitem__(od, 'spam')
with self.assertRaises(KeyError):
repr(od)
def test_dict_clear(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
od['spam'] = 1
od['ham'] = 2
dict.clear(od)
self.assertNotIn('NULL', repr(od))
def test_dict_pop(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
od['spam'] = 1
od['ham'] = 2
dict.pop(od, 'spam')
with self.assertRaises(KeyError):
repr(od)
def test_dict_popitem(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
od['spam'] = 1
od['ham'] = 2
dict.popitem(od)
with self.assertRaises(KeyError):
repr(od)
def test_dict_setdefault(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
dict.setdefault(od, 'spam', 1)
self.assertNotIn('NULL', repr(od))
def test_dict_update(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
dict.update(od, [('spam', 1)])
self.assertNotIn('NULL', repr(od))
class PurePythonOrderedDictTests(OrderedDictTests, unittest.TestCase):
module = py_coll
OrderedDict = py_coll.OrderedDict
@unittest.skipUnless(c_coll, 'requires the C version of the collections module')
class CPythonOrderedDictTests(OrderedDictTests, unittest.TestCase):
module = c_coll
OrderedDict = c_coll.OrderedDict
check_sizeof = support.check_sizeof
@support.cpython_only
def test_sizeof_exact(self):
OrderedDict = self.OrderedDict
calcsize = struct.calcsize
size = support.calcobjsize
check = self.check_sizeof
basicsize = size('n2P' + '3PnPn2P') + calcsize('2nPn')
entrysize = calcsize('n2P') + calcsize('P')
nodesize = calcsize('Pn2P')
od = OrderedDict()
check(od, basicsize + 8*entrysize)
od.x = 1
check(od, basicsize + 8*entrysize)
od.update([(i, i) for i in range(3)])
check(od, basicsize + 8*entrysize + 3*nodesize)
od.update([(i, i) for i in range(3, 10)])
check(od, basicsize + 16*entrysize + 10*nodesize)
check(od.keys(), size('P'))
check(od.items(), size('P'))
check(od.values(), size('P'))
itersize = size('iP2n2P')
check(iter(od), itersize)
check(iter(od.keys()), itersize)
check(iter(od.items()), itersize)
check(iter(od.values()), itersize)
def test_key_change_during_iteration(self):
OrderedDict = self.OrderedDict
od = OrderedDict.fromkeys('abcde')
self.assertEqual(list(od), list('abcde'))
with self.assertRaises(RuntimeError):
for i, k in enumerate(od):
od.move_to_end(k)
self.assertLess(i, 5)
with self.assertRaises(RuntimeError):
for k in od:
od['f'] = None
with self.assertRaises(RuntimeError):
for k in od:
del od['c']
self.assertEqual(list(od), list('bdeaf'))
class PurePythonOrderedDictSubclassTests(PurePythonOrderedDictTests):
module = py_coll
class OrderedDict(py_coll.OrderedDict):
pass
class CPythonOrderedDictSubclassTests(CPythonOrderedDictTests):
module = c_coll
class OrderedDict(c_coll.OrderedDict):
pass
class PurePythonGeneralMappingTests(mapping_tests.BasicTestMappingProtocol):
@classmethod
def setUpClass(cls):
cls.type2test = py_coll.OrderedDict
def test_popitem(self):
d = self._empty_mapping()
self.assertRaises(KeyError, d.popitem)
@unittest.skipUnless(c_coll, 'requires the C version of the collections module')
class CPythonGeneralMappingTests(mapping_tests.BasicTestMappingProtocol):
@classmethod
def setUpClass(cls):
cls.type2test = c_coll.OrderedDict
def test_popitem(self):
d = self._empty_mapping()
self.assertRaises(KeyError, d.popitem)
class PurePythonSubclassMappingTests(mapping_tests.BasicTestMappingProtocol):
@classmethod
def setUpClass(cls):
class MyOrderedDict(py_coll.OrderedDict):
pass
cls.type2test = MyOrderedDict
def test_popitem(self):
d = self._empty_mapping()
self.assertRaises(KeyError, d.popitem)
@unittest.skipUnless(c_coll, 'requires the C version of the collections module')
class CPythonSubclassMappingTests(mapping_tests.BasicTestMappingProtocol):
@classmethod
def setUpClass(cls):
class MyOrderedDict(c_coll.OrderedDict):
pass
cls.type2test = MyOrderedDict
def test_popitem(self):
d = self._empty_mapping()
self.assertRaises(KeyError, d.popitem)
if __name__ == "__main__":
unittest.main()