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"""
Test implementation of the PEP 509: dictionary versioning.
"""
import unittest
from test.support import import_helper
# PEP 509 is implemented in CPython but other Python implementations
# don't require to implement it
_testcapi = import_helper.import_module('_testcapi')
class DictVersionTests(unittest.TestCase):
type2test = dict
def setUp(self):
self.seen_versions = set()
self.dict = None
def check_version_unique(self, mydict):
version = _testcapi.dict_get_version(mydict)
self.assertNotIn(version, self.seen_versions)
self.seen_versions.add(version)
def check_version_changed(self, mydict, method, *args, **kw):
result = method(*args, **kw)
self.check_version_unique(mydict)
return result
def check_version_dont_change(self, mydict, method, *args, **kw):
version1 = _testcapi.dict_get_version(mydict)
self.seen_versions.add(version1)
result = method(*args, **kw)
version2 = _testcapi.dict_get_version(mydict)
self.assertEqual(version2, version1, "version changed")
return result
def new_dict(self, *args, **kw):
d = self.type2test(*args, **kw)
self.check_version_unique(d)
return d
def test_constructor(self):
# new empty dictionaries must all have an unique version
empty1 = self.new_dict()
empty2 = self.new_dict()
empty3 = self.new_dict()
# non-empty dictionaries must also have an unique version
nonempty1 = self.new_dict(x='x')
nonempty2 = self.new_dict(x='x', y='y')
def test_copy(self):
d = self.new_dict(a=1, b=2)
d2 = self.check_version_dont_change(d, d.copy)
# dict.copy() must create a dictionary with a new unique version
self.check_version_unique(d2)
def test_setitem(self):
d = self.new_dict()
# creating new keys must change the version
self.check_version_changed(d, d.__setitem__, 'x', 'x')
self.check_version_changed(d, d.__setitem__, 'y', 'y')
# changing values must change the version
self.check_version_changed(d, d.__setitem__, 'x', 1)
self.check_version_changed(d, d.__setitem__, 'y', 2)
def test_setitem_same_value(self):
value = object()
d = self.new_dict()
# setting a key must change the version
self.check_version_changed(d, d.__setitem__, 'key', value)
# setting a key to the same value with dict.__setitem__
# must change the version
self.check_version_dont_change(d, d.__setitem__, 'key', value)
# setting a key to the same value with dict.update
# must change the version
self.check_version_dont_change(d, d.update, key=value)
d2 = self.new_dict(key=value)
self.check_version_dont_change(d, d.update, d2)
def test_setitem_equal(self):
class AlwaysEqual:
def __eq__(self, other):
return True
value1 = AlwaysEqual()
value2 = AlwaysEqual()
self.assertTrue(value1 == value2)
self.assertFalse(value1 != value2)
self.assertIsNot(value1, value2)
d = self.new_dict()
self.check_version_changed(d, d.__setitem__, 'key', value1)
self.assertIs(d['key'], value1)
# setting a key to a value equal to the current value
# with dict.__setitem__() must change the version
self.check_version_changed(d, d.__setitem__, 'key', value2)
self.assertIs(d['key'], value2)
# setting a key to a value equal to the current value
# with dict.update() must change the version
self.check_version_changed(d, d.update, key=value1)
self.assertIs(d['key'], value1)
d2 = self.new_dict(key=value2)
self.check_version_changed(d, d.update, d2)
self.assertIs(d['key'], value2)
def test_setdefault(self):
d = self.new_dict()
# setting a key with dict.setdefault() must change the version
self.check_version_changed(d, d.setdefault, 'key', 'value1')
# don't change the version if the key already exists
self.check_version_dont_change(d, d.setdefault, 'key', 'value2')
def test_delitem(self):
d = self.new_dict(key='value')
# deleting a key with dict.__delitem__() must change the version
self.check_version_changed(d, d.__delitem__, 'key')
# don't change the version if the key doesn't exist
self.check_version_dont_change(d, self.assertRaises, KeyError,
d.__delitem__, 'key')
def test_pop(self):
d = self.new_dict(key='value')
# pop() must change the version if the key exists
self.check_version_changed(d, d.pop, 'key')
# pop() must not change the version if the key does not exist
self.check_version_dont_change(d, self.assertRaises, KeyError,
d.pop, 'key')
def test_popitem(self):
d = self.new_dict(key='value')
# popitem() must change the version if the dict is not empty
self.check_version_changed(d, d.popitem)
# popitem() must not change the version if the dict is empty
self.check_version_dont_change(d, self.assertRaises, KeyError,
d.popitem)
def test_update(self):
d = self.new_dict(key='value')
# update() calling with no argument must not change the version
self.check_version_dont_change(d, d.update)
# update() must change the version
self.check_version_changed(d, d.update, key='new value')
d2 = self.new_dict(key='value 3')
self.check_version_changed(d, d.update, d2)
def test_clear(self):
d = self.new_dict(key='value')
# clear() must change the version if the dict is not empty
self.check_version_changed(d, d.clear)
# clear() must not change the version if the dict is empty
self.check_version_dont_change(d, d.clear)
class Dict(dict):
pass
class DictSubtypeVersionTests(DictVersionTests):
type2test = Dict
if __name__ == "__main__":
unittest.main()
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