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cpython/Lib/test/test_functools.py

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import abc
import builtins
import collections
import collections.abc
import copy
from itertools import permutations
import pickle
from random import choice
import sys
from test import support
import threading
import time
import typing
import unittest
import unittest.mock
import weakref
import gc
from weakref import proxy
import contextlib
from inspect import Signature
from test.support import import_helper
from test.support import threading_helper
import functools
py_functools = import_helper.import_fresh_module('functools',
blocked=['_functools'])
c_functools = import_helper.import_fresh_module('functools',
fresh=['_functools'])
decimal = import_helper.import_fresh_module('decimal', fresh=['_decimal'])
_partial_types = [py_functools.partial]
if c_functools:
_partial_types.append(c_functools.partial)
@contextlib.contextmanager
def replaced_module(name, replacement):
original_module = sys.modules[name]
sys.modules[name] = replacement
try:
yield
finally:
sys.modules[name] = original_module
def capture(*args, **kw):
"""capture all positional and keyword arguments"""
return args, kw
def signature(part):
""" return the signature of a partial object """
return (part.func, part.args, part.keywords, part.__dict__)
class MyTuple(tuple):
pass
class BadTuple(tuple):
def __add__(self, other):
return list(self) + list(other)
class MyDict(dict):
pass
class TestPartial:
def test_basic_examples(self):
p = self.partial(capture, 1, 2, a=10, b=20)
self.assertTrue(callable(p))
self.assertEqual(p(3, 4, b=30, c=40),
((1, 2, 3, 4), dict(a=10, b=30, c=40)))
p = self.partial(map, lambda x: x*10)
self.assertEqual(list(p([1,2,3,4])), [10, 20, 30, 40])
def test_attributes(self):
p = self.partial(capture, 1, 2, a=10, b=20)
# attributes should be readable
self.assertEqual(p.func, capture)
self.assertEqual(p.args, (1, 2))
self.assertEqual(p.keywords, dict(a=10, b=20))
def test_argument_checking(self):
self.assertRaises(TypeError, self.partial) # need at least a func arg
try:
self.partial(2)()
except TypeError:
pass
else:
self.fail('First arg not checked for callability')
def test_protection_of_callers_dict_argument(self):
# a caller's dictionary should not be altered by partial
def func(a=10, b=20):
return a
d = {'a':3}
p = self.partial(func, a=5)
self.assertEqual(p(**d), 3)
self.assertEqual(d, {'a':3})
p(b=7)
self.assertEqual(d, {'a':3})
def test_kwargs_copy(self):
# Issue #29532: Altering a kwarg dictionary passed to a constructor
# should not affect a partial object after creation
d = {'a': 3}
p = self.partial(capture, **d)
self.assertEqual(p(), ((), {'a': 3}))
d['a'] = 5
self.assertEqual(p(), ((), {'a': 3}))
def test_arg_combinations(self):
# exercise special code paths for zero args in either partial
# object or the caller
p = self.partial(capture)
self.assertEqual(p(), ((), {}))
self.assertEqual(p(1,2), ((1,2), {}))
p = self.partial(capture, 1, 2)
self.assertEqual(p(), ((1,2), {}))
self.assertEqual(p(3,4), ((1,2,3,4), {}))
def test_kw_combinations(self):
# exercise special code paths for no keyword args in
# either the partial object or the caller
p = self.partial(capture)
self.assertEqual(p.keywords, {})
self.assertEqual(p(), ((), {}))
self.assertEqual(p(a=1), ((), {'a':1}))
p = self.partial(capture, a=1)
self.assertEqual(p.keywords, {'a':1})
self.assertEqual(p(), ((), {'a':1}))
self.assertEqual(p(b=2), ((), {'a':1, 'b':2}))
# keyword args in the call override those in the partial object
self.assertEqual(p(a=3, b=2), ((), {'a':3, 'b':2}))
def test_positional(self):
# make sure positional arguments are captured correctly
for args in [(), (0,), (0,1), (0,1,2), (0,1,2,3)]:
p = self.partial(capture, *args)
expected = args + ('x',)
got, empty = p('x')
self.assertTrue(expected == got and empty == {})
def test_keyword(self):
# make sure keyword arguments are captured correctly
for a in ['a', 0, None, 3.5]:
p = self.partial(capture, a=a)
expected = {'a':a,'x':None}
empty, got = p(x=None)
self.assertTrue(expected == got and empty == ())
def test_no_side_effects(self):
# make sure there are no side effects that affect subsequent calls
p = self.partial(capture, 0, a=1)
args1, kw1 = p(1, b=2)
self.assertTrue(args1 == (0,1) and kw1 == {'a':1,'b':2})
args2, kw2 = p()
self.assertTrue(args2 == (0,) and kw2 == {'a':1})
def test_error_propagation(self):
def f(x, y):
x / y
self.assertRaises(ZeroDivisionError, self.partial(f, 1, 0))
self.assertRaises(ZeroDivisionError, self.partial(f, 1), 0)
self.assertRaises(ZeroDivisionError, self.partial(f), 1, 0)
self.assertRaises(ZeroDivisionError, self.partial(f, y=0), 1)
def test_weakref(self):
f = self.partial(int, base=16)
p = proxy(f)
self.assertEqual(f.func, p.func)
f = None
support.gc_collect() # For PyPy or other GCs.
self.assertRaises(ReferenceError, getattr, p, 'func')
def test_with_bound_and_unbound_methods(self):
data = list(map(str, range(10)))
join = self.partial(str.join, '')
self.assertEqual(join(data), '0123456789')
join = self.partial(''.join)
self.assertEqual(join(data), '0123456789')
def test_nested_optimization(self):
partial = self.partial
inner = partial(signature, 'asdf')
nested = partial(inner, bar=True)
flat = partial(signature, 'asdf', bar=True)
self.assertEqual(signature(nested), signature(flat))
def test_nested_partial_with_attribute(self):
# see issue 25137
partial = self.partial
def foo(bar):
return bar
p = partial(foo, 'first')
p2 = partial(p, 'second')
p2.new_attr = 'spam'
self.assertEqual(p2.new_attr, 'spam')
def test_repr(self):
args = (object(), object())
args_repr = ', '.join(repr(a) for a in args)
kwargs = {'a': object(), 'b': object()}
kwargs_reprs = ['a={a!r}, b={b!r}'.format_map(kwargs),
'b={b!r}, a={a!r}'.format_map(kwargs)]
if self.partial in _partial_types:
name = 'functools.partial'
else:
name = self.partial.__name__
f = self.partial(capture)
self.assertEqual(f'{name}({capture!r})', repr(f))
f = self.partial(capture, *args)
self.assertEqual(f'{name}({capture!r}, {args_repr})', repr(f))
f = self.partial(capture, **kwargs)
self.assertIn(repr(f),
[f'{name}({capture!r}, {kwargs_repr})'
for kwargs_repr in kwargs_reprs])
f = self.partial(capture, *args, **kwargs)
self.assertIn(repr(f),
[f'{name}({capture!r}, {args_repr}, {kwargs_repr})'
for kwargs_repr in kwargs_reprs])
def test_recursive_repr(self):
if self.partial in _partial_types:
name = 'functools.partial'
else:
name = self.partial.__name__
f = self.partial(capture)
f.__setstate__((f, (), {}, {}))
try:
self.assertEqual(repr(f), '%s(...)' % (name,))
finally:
f.__setstate__((capture, (), {}, {}))
f = self.partial(capture)
f.__setstate__((capture, (f,), {}, {}))
try:
self.assertEqual(repr(f), '%s(%r, ...)' % (name, capture,))
finally:
f.__setstate__((capture, (), {}, {}))
f = self.partial(capture)
f.__setstate__((capture, (), {'a': f}, {}))
try:
self.assertEqual(repr(f), '%s(%r, a=...)' % (name, capture,))
finally:
f.__setstate__((capture, (), {}, {}))
def test_pickle(self):
with replaced_module('functools', self.module):
f = self.partial(signature, ['asdf'], bar=[True])
f.attr = []
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
f_copy = pickle.loads(pickle.dumps(f, proto))
self.assertEqual(signature(f_copy), signature(f))
def test_copy(self):
f = self.partial(signature, ['asdf'], bar=[True])
f.attr = []
f_copy = copy.copy(f)
self.assertEqual(signature(f_copy), signature(f))
self.assertIs(f_copy.attr, f.attr)
self.assertIs(f_copy.args, f.args)
self.assertIs(f_copy.keywords, f.keywords)
def test_deepcopy(self):
f = self.partial(signature, ['asdf'], bar=[True])
f.attr = []
f_copy = copy.deepcopy(f)
self.assertEqual(signature(f_copy), signature(f))
self.assertIsNot(f_copy.attr, f.attr)
self.assertIsNot(f_copy.args, f.args)
self.assertIsNot(f_copy.args[0], f.args[0])
self.assertIsNot(f_copy.keywords, f.keywords)
self.assertIsNot(f_copy.keywords['bar'], f.keywords['bar'])
def test_setstate(self):
f = self.partial(signature)
f.__setstate__((capture, (1,), dict(a=10), dict(attr=[])))
self.assertEqual(signature(f),
(capture, (1,), dict(a=10), dict(attr=[])))
self.assertEqual(f(2, b=20), ((1, 2), {'a': 10, 'b': 20}))
f.__setstate__((capture, (1,), dict(a=10), None))
self.assertEqual(signature(f), (capture, (1,), dict(a=10), {}))
self.assertEqual(f(2, b=20), ((1, 2), {'a': 10, 'b': 20}))
f.__setstate__((capture, (1,), None, None))
#self.assertEqual(signature(f), (capture, (1,), {}, {}))
self.assertEqual(f(2, b=20), ((1, 2), {'b': 20}))
self.assertEqual(f(2), ((1, 2), {}))
self.assertEqual(f(), ((1,), {}))
f.__setstate__((capture, (), {}, None))
self.assertEqual(signature(f), (capture, (), {}, {}))
self.assertEqual(f(2, b=20), ((2,), {'b': 20}))
self.assertEqual(f(2), ((2,), {}))
self.assertEqual(f(), ((), {}))
def test_setstate_errors(self):
f = self.partial(signature)
self.assertRaises(TypeError, f.__setstate__, (capture, (), {}))
self.assertRaises(TypeError, f.__setstate__, (capture, (), {}, {}, None))
self.assertRaises(TypeError, f.__setstate__, [capture, (), {}, None])
self.assertRaises(TypeError, f.__setstate__, (None, (), {}, None))
self.assertRaises(TypeError, f.__setstate__, (capture, None, {}, None))
self.assertRaises(TypeError, f.__setstate__, (capture, [], {}, None))
self.assertRaises(TypeError, f.__setstate__, (capture, (), [], None))
def test_setstate_subclasses(self):
f = self.partial(signature)
f.__setstate__((capture, MyTuple((1,)), MyDict(a=10), None))
s = signature(f)
self.assertEqual(s, (capture, (1,), dict(a=10), {}))
self.assertIs(type(s[1]), tuple)
self.assertIs(type(s[2]), dict)
r = f()
self.assertEqual(r, ((1,), {'a': 10}))
self.assertIs(type(r[0]), tuple)
self.assertIs(type(r[1]), dict)
f.__setstate__((capture, BadTuple((1,)), {}, None))
s = signature(f)
self.assertEqual(s, (capture, (1,), {}, {}))
self.assertIs(type(s[1]), tuple)
r = f(2)
self.assertEqual(r, ((1, 2), {}))
self.assertIs(type(r[0]), tuple)
def test_recursive_pickle(self):
with replaced_module('functools', self.module):
f = self.partial(capture)
f.__setstate__((f, (), {}, {}))
try:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
with self.assertRaises(RecursionError):
pickle.dumps(f, proto)
finally:
f.__setstate__((capture, (), {}, {}))
f = self.partial(capture)
f.__setstate__((capture, (f,), {}, {}))
try:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
f_copy = pickle.loads(pickle.dumps(f, proto))
try:
self.assertIs(f_copy.args[0], f_copy)
finally:
f_copy.__setstate__((capture, (), {}, {}))
finally:
f.__setstate__((capture, (), {}, {}))
f = self.partial(capture)
f.__setstate__((capture, (), {'a': f}, {}))
try:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
f_copy = pickle.loads(pickle.dumps(f, proto))
try:
self.assertIs(f_copy.keywords['a'], f_copy)
finally:
f_copy.__setstate__((capture, (), {}, {}))
finally:
f.__setstate__((capture, (), {}, {}))
# Issue 6083: Reference counting bug
def test_setstate_refcount(self):
class BadSequence:
def __len__(self):
return 4
def __getitem__(self, key):
if key == 0:
return max
elif key == 1:
return tuple(range(1000000))
elif key in (2, 3):
return {}
raise IndexError
f = self.partial(object)
self.assertRaises(TypeError, f.__setstate__, BadSequence())
@unittest.skipUnless(c_functools, 'requires the C _functools module')
class TestPartialC(TestPartial, unittest.TestCase):
if c_functools:
module = c_functools
partial = c_functools.partial
def test_attributes_unwritable(self):
# attributes should not be writable
p = self.partial(capture, 1, 2, a=10, b=20)
self.assertRaises(AttributeError, setattr, p, 'func', map)
self.assertRaises(AttributeError, setattr, p, 'args', (1, 2))
self.assertRaises(AttributeError, setattr, p, 'keywords', dict(a=1, b=2))
p = self.partial(hex)
try:
del p.__dict__
except TypeError:
pass
else:
self.fail('partial object allowed __dict__ to be deleted')
def test_manually_adding_non_string_keyword(self):
p = self.partial(capture)
# Adding a non-string/unicode keyword to partial kwargs
p.keywords[1234] = 'value'
r = repr(p)
self.assertIn('1234', r)
self.assertIn("'value'", r)
with self.assertRaises(TypeError):
p()
def test_keystr_replaces_value(self):
p = self.partial(capture)
class MutatesYourDict(object):
def __str__(self):
p.keywords[self] = ['sth2']
return 'astr'
# Replacing the value during key formatting should keep the original
# value alive (at least long enough).
p.keywords[MutatesYourDict()] = ['sth']
r = repr(p)
self.assertIn('astr', r)
self.assertIn("['sth']", r)
class TestPartialPy(TestPartial, unittest.TestCase):
module = py_functools
partial = py_functools.partial
if c_functools:
class CPartialSubclass(c_functools.partial):
pass
class PyPartialSubclass(py_functools.partial):
pass
@unittest.skipUnless(c_functools, 'requires the C _functools module')
class TestPartialCSubclass(TestPartialC):
if c_functools:
partial = CPartialSubclass
# partial subclasses are not optimized for nested calls
test_nested_optimization = None
class TestPartialPySubclass(TestPartialPy):
partial = PyPartialSubclass
class TestPartialMethod(unittest.TestCase):
class A(object):
nothing = functools.partialmethod(capture)
positional = functools.partialmethod(capture, 1)
keywords = functools.partialmethod(capture, a=2)
both = functools.partialmethod(capture, 3, b=4)
spec_keywords = functools.partialmethod(capture, self=1, func=2)
nested = functools.partialmethod(positional, 5)
over_partial = functools.partialmethod(functools.partial(capture, c=6), 7)
static = functools.partialmethod(staticmethod(capture), 8)
cls = functools.partialmethod(classmethod(capture), d=9)
a = A()
def test_arg_combinations(self):
self.assertEqual(self.a.nothing(), ((self.a,), {}))
self.assertEqual(self.a.nothing(5), ((self.a, 5), {}))
self.assertEqual(self.a.nothing(c=6), ((self.a,), {'c': 6}))
self.assertEqual(self.a.nothing(5, c=6), ((self.a, 5), {'c': 6}))
self.assertEqual(self.a.positional(), ((self.a, 1), {}))
self.assertEqual(self.a.positional(5), ((self.a, 1, 5), {}))
self.assertEqual(self.a.positional(c=6), ((self.a, 1), {'c': 6}))
self.assertEqual(self.a.positional(5, c=6), ((self.a, 1, 5), {'c': 6}))
self.assertEqual(self.a.keywords(), ((self.a,), {'a': 2}))
self.assertEqual(self.a.keywords(5), ((self.a, 5), {'a': 2}))
self.assertEqual(self.a.keywords(c=6), ((self.a,), {'a': 2, 'c': 6}))
self.assertEqual(self.a.keywords(5, c=6), ((self.a, 5), {'a': 2, 'c': 6}))
self.assertEqual(self.a.both(), ((self.a, 3), {'b': 4}))
self.assertEqual(self.a.both(5), ((self.a, 3, 5), {'b': 4}))
self.assertEqual(self.a.both(c=6), ((self.a, 3), {'b': 4, 'c': 6}))
self.assertEqual(self.a.both(5, c=6), ((self.a, 3, 5), {'b': 4, 'c': 6}))
self.assertEqual(self.A.both(self.a, 5, c=6), ((self.a, 3, 5), {'b': 4, 'c': 6}))
self.assertEqual(self.a.spec_keywords(), ((self.a,), {'self': 1, 'func': 2}))
def test_nested(self):
self.assertEqual(self.a.nested(), ((self.a, 1, 5), {}))
self.assertEqual(self.a.nested(6), ((self.a, 1, 5, 6), {}))
self.assertEqual(self.a.nested(d=7), ((self.a, 1, 5), {'d': 7}))
self.assertEqual(self.a.nested(6, d=7), ((self.a, 1, 5, 6), {'d': 7}))
self.assertEqual(self.A.nested(self.a, 6, d=7), ((self.a, 1, 5, 6), {'d': 7}))
def test_over_partial(self):
self.assertEqual(self.a.over_partial(), ((self.a, 7), {'c': 6}))
self.assertEqual(self.a.over_partial(5), ((self.a, 7, 5), {'c': 6}))
self.assertEqual(self.a.over_partial(d=8), ((self.a, 7), {'c': 6, 'd': 8}))
self.assertEqual(self.a.over_partial(5, d=8), ((self.a, 7, 5), {'c': 6, 'd': 8}))
self.assertEqual(self.A.over_partial(self.a, 5, d=8), ((self.a, 7, 5), {'c': 6, 'd': 8}))
def test_bound_method_introspection(self):
obj = self.a
self.assertIs(obj.both.__self__, obj)
self.assertIs(obj.nested.__self__, obj)
self.assertIs(obj.over_partial.__self__, obj)
self.assertIs(obj.cls.__self__, self.A)
self.assertIs(self.A.cls.__self__, self.A)
def test_unbound_method_retrieval(self):
obj = self.A
self.assertFalse(hasattr(obj.both, "__self__"))
self.assertFalse(hasattr(obj.nested, "__self__"))
self.assertFalse(hasattr(obj.over_partial, "__self__"))
self.assertFalse(hasattr(obj.static, "__self__"))
self.assertFalse(hasattr(self.a.static, "__self__"))
def test_descriptors(self):
for obj in [self.A, self.a]:
with self.subTest(obj=obj):
self.assertEqual(obj.static(), ((8,), {}))
self.assertEqual(obj.static(5), ((8, 5), {}))
self.assertEqual(obj.static(d=8), ((8,), {'d': 8}))
self.assertEqual(obj.static(5, d=8), ((8, 5), {'d': 8}))
self.assertEqual(obj.cls(), ((self.A,), {'d': 9}))
self.assertEqual(obj.cls(5), ((self.A, 5), {'d': 9}))
self.assertEqual(obj.cls(c=8), ((self.A,), {'c': 8, 'd': 9}))
self.assertEqual(obj.cls(5, c=8), ((self.A, 5), {'c': 8, 'd': 9}))
def test_overriding_keywords(self):
self.assertEqual(self.a.keywords(a=3), ((self.a,), {'a': 3}))
self.assertEqual(self.A.keywords(self.a, a=3), ((self.a,), {'a': 3}))
def test_invalid_args(self):
with self.assertRaises(TypeError):
class B(object):
method = functools.partialmethod(None, 1)
with self.assertRaises(TypeError):
class B:
method = functools.partialmethod()
with self.assertRaises(TypeError):
class B:
method = functools.partialmethod(func=capture, a=1)
def test_repr(self):
self.assertEqual(repr(vars(self.A)['both']),
'functools.partialmethod({}, 3, b=4)'.format(capture))
def test_abstract(self):
class Abstract(abc.ABCMeta):
@abc.abstractmethod
def add(self, x, y):
pass
add5 = functools.partialmethod(add, 5)
self.assertTrue(Abstract.add.__isabstractmethod__)
self.assertTrue(Abstract.add5.__isabstractmethod__)
for func in [self.A.static, self.A.cls, self.A.over_partial, self.A.nested, self.A.both]:
self.assertFalse(getattr(func, '__isabstractmethod__', False))
def test_positional_only(self):
def f(a, b, /):
return a + b
p = functools.partial(f, 1)
self.assertEqual(p(2), f(1, 2))
class TestUpdateWrapper(unittest.TestCase):
def check_wrapper(self, wrapper, wrapped,
assigned=functools.WRAPPER_ASSIGNMENTS,
updated=functools.WRAPPER_UPDATES):
# Check attributes were assigned
for name in assigned:
self.assertIs(getattr(wrapper, name), getattr(wrapped, name))
# Check attributes were updated
for name in updated:
wrapper_attr = getattr(wrapper, name)
wrapped_attr = getattr(wrapped, name)
for key in wrapped_attr:
if name == "__dict__" and key == "__wrapped__":
# __wrapped__ is overwritten by the update code
continue
self.assertIs(wrapped_attr[key], wrapper_attr[key])
# Check __wrapped__
self.assertIs(wrapper.__wrapped__, wrapped)
def _default_update(self):
def f[T](a:'This is a new annotation'):
"""This is a test"""
pass
f.attr = 'This is also a test'
f.__wrapped__ = "This is a bald faced lie"
def wrapper(b:'This is the prior annotation'):
pass
functools.update_wrapper(wrapper, f)
return wrapper, f
def test_default_update(self):
wrapper, f = self._default_update()
self.check_wrapper(wrapper, f)
T, = f.__type_params__
self.assertIs(wrapper.__wrapped__, f)
self.assertEqual(wrapper.__name__, 'f')
self.assertEqual(wrapper.__qualname__, f.__qualname__)
self.assertEqual(wrapper.attr, 'This is also a test')
self.assertEqual(wrapper.__annotations__['a'], 'This is a new annotation')
self.assertNotIn('b', wrapper.__annotations__)
self.assertEqual(wrapper.__type_params__, (T,))
@unittest.skipIf(sys.flags.optimize >= 2,
"Docstrings are omitted with -O2 and above")
def test_default_update_doc(self):
wrapper, f = self._default_update()
self.assertEqual(wrapper.__doc__, 'This is a test')
def test_no_update(self):
def f():
"""This is a test"""
pass
f.attr = 'This is also a test'
def wrapper():
pass
functools.update_wrapper(wrapper, f, (), ())
self.check_wrapper(wrapper, f, (), ())
self.assertEqual(wrapper.__name__, 'wrapper')
self.assertNotEqual(wrapper.__qualname__, f.__qualname__)
self.assertEqual(wrapper.__doc__, None)
self.assertEqual(wrapper.__annotations__, {})
self.assertFalse(hasattr(wrapper, 'attr'))
def test_selective_update(self):
def f():
pass
f.attr = 'This is a different test'
f.dict_attr = dict(a=1, b=2, c=3)
def wrapper():
pass
wrapper.dict_attr = {}
assign = ('attr',)
update = ('dict_attr',)
functools.update_wrapper(wrapper, f, assign, update)
self.check_wrapper(wrapper, f, assign, update)
self.assertEqual(wrapper.__name__, 'wrapper')
self.assertNotEqual(wrapper.__qualname__, f.__qualname__)
self.assertEqual(wrapper.__doc__, None)
self.assertEqual(wrapper.attr, 'This is a different test')
self.assertEqual(wrapper.dict_attr, f.dict_attr)
def test_missing_attributes(self):
def f():
pass
def wrapper():
pass
wrapper.dict_attr = {}
assign = ('attr',)
update = ('dict_attr',)
# Missing attributes on wrapped object are ignored
functools.update_wrapper(wrapper, f, assign, update)
self.assertNotIn('attr', wrapper.__dict__)
self.assertEqual(wrapper.dict_attr, {})
# Wrapper must have expected attributes for updating
del wrapper.dict_attr
with self.assertRaises(AttributeError):
functools.update_wrapper(wrapper, f, assign, update)
wrapper.dict_attr = 1
with self.assertRaises(AttributeError):
functools.update_wrapper(wrapper, f, assign, update)
@support.requires_docstrings
@unittest.skipIf(sys.flags.optimize >= 2,
"Docstrings are omitted with -O2 and above")
def test_builtin_update(self):
# Test for bug #1576241
def wrapper():
pass
functools.update_wrapper(wrapper, max)
self.assertEqual(wrapper.__name__, 'max')
self.assertTrue(wrapper.__doc__.startswith('max('))
self.assertEqual(wrapper.__annotations__, {})
class TestWraps(TestUpdateWrapper):
def _default_update(self):
def f():
"""This is a test"""
pass
f.attr = 'This is also a test'
f.__wrapped__ = "This is still a bald faced lie"
@functools.wraps(f)
def wrapper():
pass
return wrapper, f
def test_default_update(self):
wrapper, f = self._default_update()
self.check_wrapper(wrapper, f)
self.assertEqual(wrapper.__name__, 'f')
self.assertEqual(wrapper.__qualname__, f.__qualname__)
self.assertEqual(wrapper.attr, 'This is also a test')
@unittest.skipIf(sys.flags.optimize >= 2,
"Docstrings are omitted with -O2 and above")
def test_default_update_doc(self):
wrapper, _ = self._default_update()
self.assertEqual(wrapper.__doc__, 'This is a test')
def test_no_update(self):
def f():
"""This is a test"""
pass
f.attr = 'This is also a test'
@functools.wraps(f, (), ())
def wrapper():
pass
self.check_wrapper(wrapper, f, (), ())
self.assertEqual(wrapper.__name__, 'wrapper')
self.assertNotEqual(wrapper.__qualname__, f.__qualname__)
self.assertEqual(wrapper.__doc__, None)
self.assertFalse(hasattr(wrapper, 'attr'))
def test_selective_update(self):
def f():
pass
f.attr = 'This is a different test'
f.dict_attr = dict(a=1, b=2, c=3)
def add_dict_attr(f):
f.dict_attr = {}
return f
assign = ('attr',)
update = ('dict_attr',)
@functools.wraps(f, assign, update)
@add_dict_attr
def wrapper():
pass
self.check_wrapper(wrapper, f, assign, update)
self.assertEqual(wrapper.__name__, 'wrapper')
self.assertNotEqual(wrapper.__qualname__, f.__qualname__)
self.assertEqual(wrapper.__doc__, None)
self.assertEqual(wrapper.attr, 'This is a different test')
self.assertEqual(wrapper.dict_attr, f.dict_attr)
class TestReduce:
def test_reduce(self):
class Squares:
def __init__(self, max):
self.max = max
self.sofar = []
def __len__(self):
return len(self.sofar)
def __getitem__(self, i):
if not 0 <= i < self.max: raise IndexError
n = len(self.sofar)
while n <= i:
self.sofar.append(n*n)
n += 1
return self.sofar[i]
def add(x, y):
return x + y
self.assertEqual(self.reduce(add, ['a', 'b', 'c'], ''), 'abc')
self.assertEqual(
self.reduce(add, [['a', 'c'], [], ['d', 'w']], []),
['a','c','d','w']
)
self.assertEqual(self.reduce(lambda x, y: x*y, range(2,8), 1), 5040)
self.assertEqual(
self.reduce(lambda x, y: x*y, range(2,21), 1),
2432902008176640000
)
self.assertEqual(self.reduce(add, Squares(10)), 285)
self.assertEqual(self.reduce(add, Squares(10), 0), 285)
self.assertEqual(self.reduce(add, Squares(0), 0), 0)
self.assertRaises(TypeError, self.reduce)
self.assertRaises(TypeError, self.reduce, 42, 42)
self.assertRaises(TypeError, self.reduce, 42, 42, 42)
self.assertEqual(self.reduce(42, "1"), "1") # func is never called with one item
self.assertEqual(self.reduce(42, "", "1"), "1") # func is never called with one item
self.assertRaises(TypeError, self.reduce, 42, (42, 42))
self.assertRaises(TypeError, self.reduce, add, []) # arg 2 must not be empty sequence with no initial value
self.assertRaises(TypeError, self.reduce, add, "")
self.assertRaises(TypeError, self.reduce, add, ())
self.assertRaises(TypeError, self.reduce, add, object())
class TestFailingIter:
def __iter__(self):
raise RuntimeError
self.assertRaises(RuntimeError, self.reduce, add, TestFailingIter())
self.assertEqual(self.reduce(add, [], None), None)
self.assertEqual(self.reduce(add, [], 42), 42)
class BadSeq:
def __getitem__(self, index):
raise ValueError
self.assertRaises(ValueError, self.reduce, 42, BadSeq())
# Test reduce()'s use of iterators.
def test_iterator_usage(self):
class SequenceClass:
def __init__(self, n):
self.n = n
def __getitem__(self, i):
if 0 <= i < self.n:
return i
else:
raise IndexError
from operator import add
self.assertEqual(self.reduce(add, SequenceClass(5)), 10)
self.assertEqual(self.reduce(add, SequenceClass(5), 42), 52)
self.assertRaises(TypeError, self.reduce, add, SequenceClass(0))
self.assertEqual(self.reduce(add, SequenceClass(0), 42), 42)
self.assertEqual(self.reduce(add, SequenceClass(1)), 0)
self.assertEqual(self.reduce(add, SequenceClass(1), 42), 42)
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(self.reduce(add, d), "".join(d.keys()))
@unittest.skipUnless(c_functools, 'requires the C _functools module')
class TestReduceC(TestReduce, unittest.TestCase):
if c_functools:
reduce = c_functools.reduce
class TestReducePy(TestReduce, unittest.TestCase):
reduce = staticmethod(py_functools.reduce)
class TestCmpToKey:
def test_cmp_to_key(self):
def cmp1(x, y):
return (x > y) - (x < y)
key = self.cmp_to_key(cmp1)
self.assertEqual(key(3), key(3))
self.assertGreater(key(3), key(1))
self.assertGreaterEqual(key(3), key(3))
def cmp2(x, y):
return int(x) - int(y)
key = self.cmp_to_key(cmp2)
self.assertEqual(key(4.0), key('4'))
self.assertLess(key(2), key('35'))
self.assertLessEqual(key(2), key('35'))
self.assertNotEqual(key(2), key('35'))
def test_cmp_to_key_arguments(self):
def cmp1(x, y):
return (x > y) - (x < y)
key = self.cmp_to_key(mycmp=cmp1)
self.assertEqual(key(obj=3), key(obj=3))
self.assertGreater(key(obj=3), key(obj=1))
with self.assertRaises((TypeError, AttributeError)):
key(3) > 1 # rhs is not a K object
with self.assertRaises((TypeError, AttributeError)):
1 < key(3) # lhs is not a K object
with self.assertRaises(TypeError):
key = self.cmp_to_key() # too few args
with self.assertRaises(TypeError):
key = self.cmp_to_key(cmp1, None) # too many args
key = self.cmp_to_key(cmp1)
with self.assertRaises(TypeError):
key() # too few args
with self.assertRaises(TypeError):
key(None, None) # too many args
def test_bad_cmp(self):
def cmp1(x, y):
raise ZeroDivisionError
key = self.cmp_to_key(cmp1)
with self.assertRaises(ZeroDivisionError):
key(3) > key(1)
class BadCmp:
def __lt__(self, other):
raise ZeroDivisionError
def cmp1(x, y):
return BadCmp()
with self.assertRaises(ZeroDivisionError):
key(3) > key(1)
def test_obj_field(self):
def cmp1(x, y):
return (x > y) - (x < y)
key = self.cmp_to_key(mycmp=cmp1)
self.assertEqual(key(50).obj, 50)
def test_sort_int(self):
def mycmp(x, y):
return y - x
self.assertEqual(sorted(range(5), key=self.cmp_to_key(mycmp)),
[4, 3, 2, 1, 0])
def test_sort_int_str(self):
def mycmp(x, y):
x, y = int(x), int(y)
return (x > y) - (x < y)
values = [5, '3', 7, 2, '0', '1', 4, '10', 1]
values = sorted(values, key=self.cmp_to_key(mycmp))
self.assertEqual([int(value) for value in values],
[0, 1, 1, 2, 3, 4, 5, 7, 10])
def test_hash(self):
def mycmp(x, y):
return y - x
key = self.cmp_to_key(mycmp)
k = key(10)
self.assertRaises(TypeError, hash, k)
self.assertNotIsInstance(k, collections.abc.Hashable)
@unittest.skipIf(support.MISSING_C_DOCSTRINGS,
"Signature information for builtins requires docstrings")
def test_cmp_to_signature(self):
self.assertEqual(str(Signature.from_callable(self.cmp_to_key)),
'(mycmp)')
@unittest.skipUnless(c_functools, 'requires the C _functools module')
class TestCmpToKeyC(TestCmpToKey, unittest.TestCase):
if c_functools:
cmp_to_key = c_functools.cmp_to_key
@support.cpython_only
def test_disallow_instantiation(self):
# Ensure that the type disallows instantiation (bpo-43916)
support.check_disallow_instantiation(
self, type(c_functools.cmp_to_key(None))
)
class TestCmpToKeyPy(TestCmpToKey, unittest.TestCase):
cmp_to_key = staticmethod(py_functools.cmp_to_key)
class TestTotalOrdering(unittest.TestCase):
def test_total_ordering_lt(self):
@functools.total_ordering
class A:
def __init__(self, value):
self.value = value
def __lt__(self, other):
return self.value < other.value
def __eq__(self, other):
return self.value == other.value
self.assertTrue(A(1) < A(2))
self.assertTrue(A(2) > A(1))
self.assertTrue(A(1) <= A(2))
self.assertTrue(A(2) >= A(1))
self.assertTrue(A(2) <= A(2))
self.assertTrue(A(2) >= A(2))
self.assertFalse(A(1) > A(2))
def test_total_ordering_le(self):
@functools.total_ordering
class A:
def __init__(self, value):
self.value = value
def __le__(self, other):
return self.value <= other.value
def __eq__(self, other):
return self.value == other.value
self.assertTrue(A(1) < A(2))
self.assertTrue(A(2) > A(1))
self.assertTrue(A(1) <= A(2))
self.assertTrue(A(2) >= A(1))
self.assertTrue(A(2) <= A(2))
self.assertTrue(A(2) >= A(2))
self.assertFalse(A(1) >= A(2))
def test_total_ordering_gt(self):
@functools.total_ordering
class A:
def __init__(self, value):
self.value = value
def __gt__(self, other):
return self.value > other.value
def __eq__(self, other):
return self.value == other.value
self.assertTrue(A(1) < A(2))
self.assertTrue(A(2) > A(1))
self.assertTrue(A(1) <= A(2))
self.assertTrue(A(2) >= A(1))
self.assertTrue(A(2) <= A(2))
self.assertTrue(A(2) >= A(2))
self.assertFalse(A(2) < A(1))
def test_total_ordering_ge(self):
@functools.total_ordering
class A:
def __init__(self, value):
self.value = value
def __ge__(self, other):
return self.value >= other.value
def __eq__(self, other):
return self.value == other.value
self.assertTrue(A(1) < A(2))
self.assertTrue(A(2) > A(1))
self.assertTrue(A(1) <= A(2))
self.assertTrue(A(2) >= A(1))
self.assertTrue(A(2) <= A(2))
self.assertTrue(A(2) >= A(2))
self.assertFalse(A(2) <= A(1))
def test_total_ordering_no_overwrite(self):
# new methods should not overwrite existing
@functools.total_ordering
class A(int):
pass
self.assertTrue(A(1) < A(2))
self.assertTrue(A(2) > A(1))
self.assertTrue(A(1) <= A(2))
self.assertTrue(A(2) >= A(1))
self.assertTrue(A(2) <= A(2))
self.assertTrue(A(2) >= A(2))
def test_no_operations_defined(self):
with self.assertRaises(ValueError):
@functools.total_ordering
class A:
pass
def test_notimplemented(self):
# Verify NotImplemented results are correctly handled
@functools.total_ordering
class ImplementsLessThan:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsLessThan):
return self.value == other.value
return False
def __lt__(self, other):
if isinstance(other, ImplementsLessThan):
return self.value < other.value
return NotImplemented
@functools.total_ordering
class ImplementsLessThanEqualTo:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsLessThanEqualTo):
return self.value == other.value
return False
def __le__(self, other):
if isinstance(other, ImplementsLessThanEqualTo):
return self.value <= other.value
return NotImplemented
@functools.total_ordering
class ImplementsGreaterThan:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsGreaterThan):
return self.value == other.value
return False
def __gt__(self, other):
if isinstance(other, ImplementsGreaterThan):
return self.value > other.value
return NotImplemented
@functools.total_ordering
class ImplementsGreaterThanEqualTo:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsGreaterThanEqualTo):
return self.value == other.value
return False
def __ge__(self, other):
if isinstance(other, ImplementsGreaterThanEqualTo):
return self.value >= other.value
return NotImplemented
self.assertIs(ImplementsLessThan(1).__le__(1), NotImplemented)
self.assertIs(ImplementsLessThan(1).__gt__(1), NotImplemented)
self.assertIs(ImplementsLessThan(1).__ge__(1), NotImplemented)
self.assertIs(ImplementsLessThanEqualTo(1).__lt__(1), NotImplemented)
self.assertIs(ImplementsLessThanEqualTo(1).__gt__(1), NotImplemented)
self.assertIs(ImplementsLessThanEqualTo(1).__ge__(1), NotImplemented)
self.assertIs(ImplementsGreaterThan(1).__lt__(1), NotImplemented)
self.assertIs(ImplementsGreaterThan(1).__gt__(1), NotImplemented)
self.assertIs(ImplementsGreaterThan(1).__ge__(1), NotImplemented)
self.assertIs(ImplementsGreaterThanEqualTo(1).__lt__(1), NotImplemented)
self.assertIs(ImplementsGreaterThanEqualTo(1).__le__(1), NotImplemented)
self.assertIs(ImplementsGreaterThanEqualTo(1).__gt__(1), NotImplemented)
def test_type_error_when_not_implemented(self):
# bug 10042; ensure stack overflow does not occur
# when decorated types return NotImplemented
@functools.total_ordering
class ImplementsLessThan:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsLessThan):
return self.value == other.value
return False
def __lt__(self, other):
if isinstance(other, ImplementsLessThan):
return self.value < other.value
return NotImplemented
@functools.total_ordering
class ImplementsGreaterThan:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsGreaterThan):
return self.value == other.value
return False
def __gt__(self, other):
if isinstance(other, ImplementsGreaterThan):
return self.value > other.value
return NotImplemented
@functools.total_ordering
class ImplementsLessThanEqualTo:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsLessThanEqualTo):
return self.value == other.value
return False
def __le__(self, other):
if isinstance(other, ImplementsLessThanEqualTo):
return self.value <= other.value
return NotImplemented
@functools.total_ordering
class ImplementsGreaterThanEqualTo:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ImplementsGreaterThanEqualTo):
return self.value == other.value
return False
def __ge__(self, other):
if isinstance(other, ImplementsGreaterThanEqualTo):
return self.value >= other.value
return NotImplemented
@functools.total_ordering
class ComparatorNotImplemented:
def __init__(self, value):
self.value = value
def __eq__(self, other):
if isinstance(other, ComparatorNotImplemented):
return self.value == other.value
return False
def __lt__(self, other):
return NotImplemented
with self.subTest("LT < 1"), self.assertRaises(TypeError):
ImplementsLessThan(-1) < 1
with self.subTest("LT < LE"), self.assertRaises(TypeError):
ImplementsLessThan(0) < ImplementsLessThanEqualTo(0)
with self.subTest("LT < GT"), self.assertRaises(TypeError):
ImplementsLessThan(1) < ImplementsGreaterThan(1)
with self.subTest("LE <= LT"), self.assertRaises(TypeError):
ImplementsLessThanEqualTo(2) <= ImplementsLessThan(2)
with self.subTest("LE <= GE"), self.assertRaises(TypeError):
ImplementsLessThanEqualTo(3) <= ImplementsGreaterThanEqualTo(3)
with self.subTest("GT > GE"), self.assertRaises(TypeError):
ImplementsGreaterThan(4) > ImplementsGreaterThanEqualTo(4)
with self.subTest("GT > LT"), self.assertRaises(TypeError):
ImplementsGreaterThan(5) > ImplementsLessThan(5)
with self.subTest("GE >= GT"), self.assertRaises(TypeError):
ImplementsGreaterThanEqualTo(6) >= ImplementsGreaterThan(6)
with self.subTest("GE >= LE"), self.assertRaises(TypeError):
ImplementsGreaterThanEqualTo(7) >= ImplementsLessThanEqualTo(7)
with self.subTest("GE when equal"):
a = ComparatorNotImplemented(8)
b = ComparatorNotImplemented(8)
self.assertEqual(a, b)
with self.assertRaises(TypeError):
a >= b
with self.subTest("LE when equal"):
a = ComparatorNotImplemented(9)
b = ComparatorNotImplemented(9)
self.assertEqual(a, b)
with self.assertRaises(TypeError):
a <= b
def test_pickle(self):
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
for name in '__lt__', '__gt__', '__le__', '__ge__':
with self.subTest(method=name, proto=proto):
method = getattr(Orderable_LT, name)
method_copy = pickle.loads(pickle.dumps(method, proto))
self.assertIs(method_copy, method)
def test_total_ordering_for_metaclasses_issue_44605(self):
@functools.total_ordering
class SortableMeta(type):
def __new__(cls, name, bases, ns):
return super().__new__(cls, name, bases, ns)
def __lt__(self, other):
if not isinstance(other, SortableMeta):
pass
return self.__name__ < other.__name__
def __eq__(self, other):
if not isinstance(other, SortableMeta):
pass
return self.__name__ == other.__name__
class B(metaclass=SortableMeta):
pass
class A(metaclass=SortableMeta):
pass
self.assertTrue(A < B)
self.assertFalse(A > B)
@functools.total_ordering
class Orderable_LT:
def __init__(self, value):
self.value = value
def __lt__(self, other):
return self.value < other.value
def __eq__(self, other):
return self.value == other.value
class TestCache:
# This tests that the pass-through is working as designed.
# The underlying functionality is tested in TestLRU.
def test_cache(self):
@self.module.cache
def fib(n):
if n < 2:
return n
return fib(n-1) + fib(n-2)
self.assertEqual([fib(n) for n in range(16)],
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610])
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
class TestLRU:
def test_lru(self):
def orig(x, y):
return 3 * x + y
f = self.module.lru_cache(maxsize=20)(orig)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(maxsize, 20)
self.assertEqual(currsize, 0)
self.assertEqual(hits, 0)
self.assertEqual(misses, 0)
domain = range(5)
for i in range(1000):
x, y = choice(domain), choice(domain)
actual = f(x, y)
expected = orig(x, y)
self.assertEqual(actual, expected)
hits, misses, maxsize, currsize = f.cache_info()
self.assertTrue(hits > misses)
self.assertEqual(hits + misses, 1000)
self.assertEqual(currsize, 20)
f.cache_clear() # test clearing
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(hits, 0)
self.assertEqual(misses, 0)
self.assertEqual(currsize, 0)
f(x, y)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(hits, 0)
self.assertEqual(misses, 1)
self.assertEqual(currsize, 1)
# Test bypassing the cache
self.assertIs(f.__wrapped__, orig)
f.__wrapped__(x, y)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(hits, 0)
self.assertEqual(misses, 1)
self.assertEqual(currsize, 1)
# test size zero (which means "never-cache")
@self.module.lru_cache(0)
def f():
nonlocal f_cnt
f_cnt += 1
return 20
self.assertEqual(f.cache_info().maxsize, 0)
f_cnt = 0
for i in range(5):
self.assertEqual(f(), 20)
self.assertEqual(f_cnt, 5)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(hits, 0)
self.assertEqual(misses, 5)
self.assertEqual(currsize, 0)
# test size one
@self.module.lru_cache(1)
def f():
nonlocal f_cnt
f_cnt += 1
return 20
self.assertEqual(f.cache_info().maxsize, 1)
f_cnt = 0
for i in range(5):
self.assertEqual(f(), 20)
self.assertEqual(f_cnt, 1)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(hits, 4)
self.assertEqual(misses, 1)
self.assertEqual(currsize, 1)
# test size two
@self.module.lru_cache(2)
def f(x):
nonlocal f_cnt
f_cnt += 1
return x*10
self.assertEqual(f.cache_info().maxsize, 2)
f_cnt = 0
for x in 7, 9, 7, 9, 7, 9, 8, 8, 8, 9, 9, 9, 8, 8, 8, 7:
# * * * *
self.assertEqual(f(x), x*10)
self.assertEqual(f_cnt, 4)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(hits, 12)
self.assertEqual(misses, 4)
self.assertEqual(currsize, 2)
def test_lru_no_args(self):
@self.module.lru_cache
def square(x):
return x ** 2
self.assertEqual(list(map(square, [10, 20, 10])),
[100, 400, 100])
self.assertEqual(square.cache_info().hits, 1)
self.assertEqual(square.cache_info().misses, 2)
self.assertEqual(square.cache_info().maxsize, 128)
self.assertEqual(square.cache_info().currsize, 2)
def test_lru_bug_35780(self):
# C version of the lru_cache was not checking to see if
# the user function call has already modified the cache
# (this arises in recursive calls and in multi-threading).
# This cause the cache to have orphan links not referenced
# by the cache dictionary.
once = True # Modified by f(x) below
@self.module.lru_cache(maxsize=10)
def f(x):
nonlocal once
rv = f'.{x}.'
if x == 20 and once:
once = False
rv = f(x)
return rv
# Fill the cache
for x in range(15):
self.assertEqual(f(x), f'.{x}.')
self.assertEqual(f.cache_info().currsize, 10)
# Make a recursive call and make sure the cache remains full
self.assertEqual(f(20), '.20.')
self.assertEqual(f.cache_info().currsize, 10)
def test_lru_bug_36650(self):
# C version of lru_cache was treating a call with an empty **kwargs
# dictionary as being distinct from a call with no keywords at all.
# This did not result in an incorrect answer, but it did trigger
# an unexpected cache miss.
@self.module.lru_cache()
def f(x):
pass
f(0)
f(0, **{})
self.assertEqual(f.cache_info().hits, 1)
def test_lru_hash_only_once(self):
# To protect against weird reentrancy bugs and to improve
# efficiency when faced with slow __hash__ methods, the
# LRU cache guarantees that it will only call __hash__
# only once per use as an argument to the cached function.
@self.module.lru_cache(maxsize=1)
def f(x, y):
return x * 3 + y
# Simulate the integer 5
mock_int = unittest.mock.Mock()
mock_int.__mul__ = unittest.mock.Mock(return_value=15)
mock_int.__hash__ = unittest.mock.Mock(return_value=999)
# Add to cache: One use as an argument gives one call
self.assertEqual(f(mock_int, 1), 16)
self.assertEqual(mock_int.__hash__.call_count, 1)
self.assertEqual(f.cache_info(), (0, 1, 1, 1))
# Cache hit: One use as an argument gives one additional call
self.assertEqual(f(mock_int, 1), 16)
self.assertEqual(mock_int.__hash__.call_count, 2)
self.assertEqual(f.cache_info(), (1, 1, 1, 1))
# Cache eviction: No use as an argument gives no additional call
self.assertEqual(f(6, 2), 20)
self.assertEqual(mock_int.__hash__.call_count, 2)
self.assertEqual(f.cache_info(), (1, 2, 1, 1))
# Cache miss: One use as an argument gives one additional call
self.assertEqual(f(mock_int, 1), 16)
self.assertEqual(mock_int.__hash__.call_count, 3)
self.assertEqual(f.cache_info(), (1, 3, 1, 1))
def test_lru_reentrancy_with_len(self):
# Test to make sure the LRU cache code isn't thrown-off by
# caching the built-in len() function. Since len() can be
# cached, we shouldn't use it inside the lru code itself.
old_len = builtins.len
try:
builtins.len = self.module.lru_cache(4)(len)
for i in [0, 0, 1, 2, 3, 3, 4, 5, 6, 1, 7, 2, 1]:
self.assertEqual(len('abcdefghijklmn'[:i]), i)
finally:
builtins.len = old_len
def test_lru_star_arg_handling(self):
# Test regression that arose in ea064ff3c10f
@self.module.lru_cache()
def f(*args):
return args
self.assertEqual(f(1, 2), (1, 2))
self.assertEqual(f((1, 2)), ((1, 2),))
def test_lru_type_error(self):
# Regression test for issue #28653.
# lru_cache was leaking when one of the arguments
# wasn't cacheable.
@self.module.lru_cache(maxsize=None)
def infinite_cache(o):
pass
@self.module.lru_cache(maxsize=10)
def limited_cache(o):
pass
with self.assertRaises(TypeError):
infinite_cache([])
with self.assertRaises(TypeError):
limited_cache([])
def test_lru_with_maxsize_none(self):
@self.module.lru_cache(maxsize=None)
def fib(n):
if n < 2:
return n
return fib(n-1) + fib(n-2)
self.assertEqual([fib(n) for n in range(16)],
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610])
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
def test_lru_with_maxsize_negative(self):
@self.module.lru_cache(maxsize=-10)
def eq(n):
return n
for i in (0, 1):
self.assertEqual([eq(n) for n in range(150)], list(range(150)))
self.assertEqual(eq.cache_info(),
self.module._CacheInfo(hits=0, misses=300, maxsize=0, currsize=0))
def test_lru_with_exceptions(self):
# Verify that user_function exceptions get passed through without
# creating a hard-to-read chained exception.
# http://bugs.python.org/issue13177
for maxsize in (None, 128):
@self.module.lru_cache(maxsize)
def func(i):
return 'abc'[i]
self.assertEqual(func(0), 'a')
with self.assertRaises(IndexError) as cm:
func(15)
self.assertIsNone(cm.exception.__context__)
# Verify that the previous exception did not result in a cached entry
with self.assertRaises(IndexError):
func(15)
def test_lru_with_types(self):
for maxsize in (None, 128):
@self.module.lru_cache(maxsize=maxsize, typed=True)
def square(x):
return x * x
self.assertEqual(square(3), 9)
self.assertEqual(type(square(3)), type(9))
self.assertEqual(square(3.0), 9.0)
self.assertEqual(type(square(3.0)), type(9.0))
self.assertEqual(square(x=3), 9)
self.assertEqual(type(square(x=3)), type(9))
self.assertEqual(square(x=3.0), 9.0)
self.assertEqual(type(square(x=3.0)), type(9.0))
self.assertEqual(square.cache_info().hits, 4)
self.assertEqual(square.cache_info().misses, 4)
def test_lru_cache_typed_is_not_recursive(self):
cached = self.module.lru_cache(typed=True)(repr)
self.assertEqual(cached(1), '1')
self.assertEqual(cached(True), 'True')
self.assertEqual(cached(1.0), '1.0')
self.assertEqual(cached(0), '0')
self.assertEqual(cached(False), 'False')
self.assertEqual(cached(0.0), '0.0')
self.assertEqual(cached((1,)), '(1,)')
self.assertEqual(cached((True,)), '(1,)')
self.assertEqual(cached((1.0,)), '(1,)')
self.assertEqual(cached((0,)), '(0,)')
self.assertEqual(cached((False,)), '(0,)')
self.assertEqual(cached((0.0,)), '(0,)')
class T(tuple):
pass
self.assertEqual(cached(T((1,))), '(1,)')
self.assertEqual(cached(T((True,))), '(1,)')
self.assertEqual(cached(T((1.0,))), '(1,)')
self.assertEqual(cached(T((0,))), '(0,)')
self.assertEqual(cached(T((False,))), '(0,)')
self.assertEqual(cached(T((0.0,))), '(0,)')
def test_lru_with_keyword_args(self):
@self.module.lru_cache()
def fib(n):
if n < 2:
return n
return fib(n=n-1) + fib(n=n-2)
self.assertEqual(
[fib(n=number) for number in range(16)],
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
)
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=28, misses=16, maxsize=128, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=0, misses=0, maxsize=128, currsize=0))
def test_lru_with_keyword_args_maxsize_none(self):
@self.module.lru_cache(maxsize=None)
def fib(n):
if n < 2:
return n
return fib(n=n-1) + fib(n=n-2)
self.assertEqual([fib(n=number) for number in range(16)],
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610])
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
self.module._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
def test_kwargs_order(self):
# PEP 468: Preserving Keyword Argument Order
@self.module.lru_cache(maxsize=10)
def f(**kwargs):
return list(kwargs.items())
self.assertEqual(f(a=1, b=2), [('a', 1), ('b', 2)])
self.assertEqual(f(b=2, a=1), [('b', 2), ('a', 1)])
self.assertEqual(f.cache_info(),
self.module._CacheInfo(hits=0, misses=2, maxsize=10, currsize=2))
def test_lru_cache_decoration(self):
def f(zomg: 'zomg_annotation'):
"""f doc string"""
return 42
g = self.module.lru_cache()(f)
for attr in self.module.WRAPPER_ASSIGNMENTS:
self.assertEqual(getattr(g, attr), getattr(f, attr))
@threading_helper.requires_working_threading()
def test_lru_cache_threaded(self):
n, m = 5, 11
def orig(x, y):
return 3 * x + y
f = self.module.lru_cache(maxsize=n*m)(orig)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(currsize, 0)
start = threading.Event()
def full(k):
start.wait(10)
for _ in range(m):
self.assertEqual(f(k, 0), orig(k, 0))
def clear():
start.wait(10)
for _ in range(2*m):
f.cache_clear()
orig_si = sys.getswitchinterval()
support.setswitchinterval(1e-6)
try:
# create n threads in order to fill cache
threads = [threading.Thread(target=full, args=[k])
for k in range(n)]
with threading_helper.start_threads(threads):
start.set()
hits, misses, maxsize, currsize = f.cache_info()
if self.module is py_functools:
# XXX: Why can be not equal?
self.assertLessEqual(misses, n)
self.assertLessEqual(hits, m*n - misses)
else:
self.assertEqual(misses, n)
self.assertEqual(hits, m*n - misses)
self.assertEqual(currsize, n)
# create n threads in order to fill cache and 1 to clear it
threads = [threading.Thread(target=clear)]
threads += [threading.Thread(target=full, args=[k])
for k in range(n)]
start.clear()
with threading_helper.start_threads(threads):
start.set()
finally:
sys.setswitchinterval(orig_si)
@threading_helper.requires_working_threading()
def test_lru_cache_threaded2(self):
# Simultaneous call with the same arguments
n, m = 5, 7
start = threading.Barrier(n+1)
pause = threading.Barrier(n+1)
stop = threading.Barrier(n+1)
@self.module.lru_cache(maxsize=m*n)
def f(x):
pause.wait(10)
return 3 * x
self.assertEqual(f.cache_info(), (0, 0, m*n, 0))
def test():
for i in range(m):
start.wait(10)
self.assertEqual(f(i), 3 * i)
stop.wait(10)
threads = [threading.Thread(target=test) for k in range(n)]
with threading_helper.start_threads(threads):
for i in range(m):
start.wait(10)
stop.reset()
pause.wait(10)
start.reset()
stop.wait(10)
pause.reset()
self.assertEqual(f.cache_info(), (0, (i+1)*n, m*n, i+1))
@threading_helper.requires_working_threading()
def test_lru_cache_threaded3(self):
@self.module.lru_cache(maxsize=2)
def f(x):
time.sleep(.01)
return 3 * x
def test(i, x):
with self.subTest(thread=i):
self.assertEqual(f(x), 3 * x, i)
threads = [threading.Thread(target=test, args=(i, v))
for i, v in enumerate([1, 2, 2, 3, 2])]
with threading_helper.start_threads(threads):
pass
def test_need_for_rlock(self):
# This will deadlock on an LRU cache that uses a regular lock
@self.module.lru_cache(maxsize=10)
def test_func(x):
'Used to demonstrate a reentrant lru_cache call within a single thread'
return x
class DoubleEq:
'Demonstrate a reentrant lru_cache call within a single thread'
def __init__(self, x):
self.x = x
def __hash__(self):
return self.x
def __eq__(self, other):
if self.x == 2:
test_func(DoubleEq(1))
return self.x == other.x
test_func(DoubleEq(1)) # Load the cache
test_func(DoubleEq(2)) # Load the cache
self.assertEqual(test_func(DoubleEq(2)), # Trigger a re-entrant __eq__ call
DoubleEq(2)) # Verify the correct return value
def test_lru_method(self):
class X(int):
f_cnt = 0
@self.module.lru_cache(2)
def f(self, x):
self.f_cnt += 1
return x*10+self
a = X(5)
b = X(5)
c = X(7)
self.assertEqual(X.f.cache_info(), (0, 0, 2, 0))
for x in 1, 2, 2, 3, 1, 1, 1, 2, 3, 3:
self.assertEqual(a.f(x), x*10 + 5)
self.assertEqual((a.f_cnt, b.f_cnt, c.f_cnt), (6, 0, 0))
self.assertEqual(X.f.cache_info(), (4, 6, 2, 2))
for x in 1, 2, 1, 1, 1, 1, 3, 2, 2, 2:
self.assertEqual(b.f(x), x*10 + 5)
self.assertEqual((a.f_cnt, b.f_cnt, c.f_cnt), (6, 4, 0))
self.assertEqual(X.f.cache_info(), (10, 10, 2, 2))
for x in 2, 1, 1, 1, 1, 2, 1, 3, 2, 1:
self.assertEqual(c.f(x), x*10 + 7)
self.assertEqual((a.f_cnt, b.f_cnt, c.f_cnt), (6, 4, 5))
self.assertEqual(X.f.cache_info(), (15, 15, 2, 2))
self.assertEqual(a.f.cache_info(), X.f.cache_info())
self.assertEqual(b.f.cache_info(), X.f.cache_info())
self.assertEqual(c.f.cache_info(), X.f.cache_info())
def test_pickle(self):
cls = self.__class__
for f in cls.cached_func[0], cls.cached_meth, cls.cached_staticmeth:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
with self.subTest(proto=proto, func=f):
f_copy = pickle.loads(pickle.dumps(f, proto))
self.assertIs(f_copy, f)
def test_copy(self):
cls = self.__class__
def orig(x, y):
return 3 * x + y
part = self.module.partial(orig, 2)
funcs = (cls.cached_func[0], cls.cached_meth, cls.cached_staticmeth,
self.module.lru_cache(2)(part))
for f in funcs:
with self.subTest(func=f):
f_copy = copy.copy(f)
self.assertIs(f_copy, f)
def test_deepcopy(self):
cls = self.__class__
def orig(x, y):
return 3 * x + y
part = self.module.partial(orig, 2)
funcs = (cls.cached_func[0], cls.cached_meth, cls.cached_staticmeth,
self.module.lru_cache(2)(part))
for f in funcs:
with self.subTest(func=f):
f_copy = copy.deepcopy(f)
self.assertIs(f_copy, f)
def test_lru_cache_parameters(self):
@self.module.lru_cache(maxsize=2)
def f():
return 1
self.assertEqual(f.cache_parameters(), {'maxsize': 2, "typed": False})
@self.module.lru_cache(maxsize=1000, typed=True)
def f():
return 1
self.assertEqual(f.cache_parameters(), {'maxsize': 1000, "typed": True})
def test_lru_cache_weakrefable(self):
@self.module.lru_cache
def test_function(x):
return x
class A:
@self.module.lru_cache
def test_method(self, x):
return (self, x)
@staticmethod
@self.module.lru_cache
def test_staticmethod(x):
return (self, x)
refs = [weakref.ref(test_function),
weakref.ref(A.test_method),
weakref.ref(A.test_staticmethod)]
for ref in refs:
self.assertIsNotNone(ref())
del A
del test_function
gc.collect()
for ref in refs:
self.assertIsNone(ref())
def test_common_signatures(self):
def orig(): ...
lru = self.module.lru_cache(1)(orig)
self.assertEqual(str(Signature.from_callable(lru.cache_info)), '()')
self.assertEqual(str(Signature.from_callable(lru.cache_clear)), '()')
@support.skip_on_s390x
@unittest.skipIf(support.is_wasi, "WASI has limited C stack")
def test_lru_recursion(self):
@self.module.lru_cache
def fib(n):
if n <= 1:
return n
return fib(n-1) + fib(n-2)
if not support.Py_DEBUG:
depth = support.Py_C_RECURSION_LIMIT*2//7
with support.infinite_recursion():
fib(depth)
if self.module == c_functools:
fib.cache_clear()
with support.infinite_recursion():
with self.assertRaises(RecursionError):
fib(10000)
@py_functools.lru_cache()
def py_cached_func(x, y):
return 3 * x + y
if c_functools:
@c_functools.lru_cache()
def c_cached_func(x, y):
return 3 * x + y
class TestLRUPy(TestLRU, unittest.TestCase):
module = py_functools
cached_func = py_cached_func,
@module.lru_cache()
def cached_meth(self, x, y):
return 3 * x + y
@staticmethod
@module.lru_cache()
def cached_staticmeth(x, y):
return 3 * x + y
@unittest.skipUnless(c_functools, 'requires the C _functools module')
class TestLRUC(TestLRU, unittest.TestCase):
if c_functools:
module = c_functools
cached_func = c_cached_func,
@module.lru_cache()
def cached_meth(self, x, y):
return 3 * x + y
@staticmethod
@module.lru_cache()
def cached_staticmeth(x, y):
return 3 * x + y
class TestSingleDispatch(unittest.TestCase):
def test_simple_overloads(self):
@functools.singledispatch
def g(obj):
return "base"
def g_int(i):
return "integer"
g.register(int, g_int)
self.assertEqual(g("str"), "base")
self.assertEqual(g(1), "integer")
self.assertEqual(g([1,2,3]), "base")
def test_mro(self):
@functools.singledispatch
def g(obj):
return "base"
class A:
pass
class C(A):
pass
class B(A):
pass
class D(C, B):
pass
def g_A(a):
return "A"
def g_B(b):
return "B"
g.register(A, g_A)
g.register(B, g_B)
self.assertEqual(g(A()), "A")
self.assertEqual(g(B()), "B")
self.assertEqual(g(C()), "A")
self.assertEqual(g(D()), "B")
def test_register_decorator(self):
@functools.singledispatch
def g(obj):
return "base"
@g.register(int)
def g_int(i):
return "int %s" % (i,)
self.assertEqual(g(""), "base")
self.assertEqual(g(12), "int 12")
self.assertIs(g.dispatch(int), g_int)
self.assertIs(g.dispatch(object), g.dispatch(str))
# Note: in the assert above this is not g.
# @singledispatch returns the wrapper.
def test_wrapping_attributes(self):
@functools.singledispatch
def g(obj):
"Simple test"
return "Test"
self.assertEqual(g.__name__, "g")
if sys.flags.optimize < 2:
self.assertEqual(g.__doc__, "Simple test")
@unittest.skipUnless(decimal, 'requires _decimal')
@support.cpython_only
def test_c_classes(self):
@functools.singledispatch
def g(obj):
return "base"
@g.register(decimal.DecimalException)
def _(obj):
return obj.args
subn = decimal.Subnormal("Exponent < Emin")
rnd = decimal.Rounded("Number got rounded")
self.assertEqual(g(subn), ("Exponent < Emin",))
self.assertEqual(g(rnd), ("Number got rounded",))
@g.register(decimal.Subnormal)
def _(obj):
return "Too small to care."
self.assertEqual(g(subn), "Too small to care.")
self.assertEqual(g(rnd), ("Number got rounded",))
def test_compose_mro(self):
# None of the examples in this test depend on haystack ordering.
c = collections.abc
mro = functools._compose_mro
bases = [c.Sequence, c.MutableMapping, c.Mapping, c.Set]
for haystack in permutations(bases):
m = mro(dict, haystack)
self.assertEqual(m, [dict, c.MutableMapping, c.Mapping,
c.Collection, c.Sized, c.Iterable,
c.Container, object])
bases = [c.Container, c.Mapping, c.MutableMapping, collections.OrderedDict]
for haystack in permutations(bases):
m = mro(collections.ChainMap, haystack)
self.assertEqual(m, [collections.ChainMap, c.MutableMapping, c.Mapping,
c.Collection, c.Sized, c.Iterable,
c.Container, object])
# If there's a generic function with implementations registered for
# both Sized and Container, passing a defaultdict to it results in an
# ambiguous dispatch which will cause a RuntimeError (see
# test_mro_conflicts).
bases = [c.Container, c.Sized, str]
for haystack in permutations(bases):
m = mro(collections.defaultdict, [c.Sized, c.Container, str])
self.assertEqual(m, [collections.defaultdict, dict, c.Sized,
c.Container, object])
# MutableSequence below is registered directly on D. In other words, it
# precedes MutableMapping which means single dispatch will always
# choose MutableSequence here.
class D(collections.defaultdict):
pass
c.MutableSequence.register(D)
bases = [c.MutableSequence, c.MutableMapping]
for haystack in permutations(bases):
m = mro(D, haystack)
self.assertEqual(m, [D, c.MutableSequence, c.Sequence, c.Reversible,
collections.defaultdict, dict, c.MutableMapping, c.Mapping,
c.Collection, c.Sized, c.Iterable, c.Container,
object])
# Container and Callable are registered on different base classes and
# a generic function supporting both should always pick the Callable
# implementation if a C instance is passed.
class C(collections.defaultdict):
def __call__(self):
pass
bases = [c.Sized, c.Callable, c.Container, c.Mapping]
for haystack in permutations(bases):
m = mro(C, haystack)
self.assertEqual(m, [C, c.Callable, collections.defaultdict, dict, c.Mapping,
c.Collection, c.Sized, c.Iterable,
c.Container, object])
def test_register_abc(self):
c = collections.abc
d = {"a": "b"}
l = [1, 2, 3]
s = {object(), None}
f = frozenset(s)
t = (1, 2, 3)
@functools.singledispatch
def g(obj):
return "base"
self.assertEqual(g(d), "base")
self.assertEqual(g(l), "base")
self.assertEqual(g(s), "base")
self.assertEqual(g(f), "base")
self.assertEqual(g(t), "base")
g.register(c.Sized, lambda obj: "sized")
self.assertEqual(g(d), "sized")
self.assertEqual(g(l), "sized")
self.assertEqual(g(s), "sized")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sized")
g.register(c.MutableMapping, lambda obj: "mutablemapping")
self.assertEqual(g(d), "mutablemapping")
self.assertEqual(g(l), "sized")
self.assertEqual(g(s), "sized")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sized")
g.register(collections.ChainMap, lambda obj: "chainmap")
self.assertEqual(g(d), "mutablemapping") # irrelevant ABCs registered
self.assertEqual(g(l), "sized")
self.assertEqual(g(s), "sized")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sized")
g.register(c.MutableSequence, lambda obj: "mutablesequence")
self.assertEqual(g(d), "mutablemapping")
self.assertEqual(g(l), "mutablesequence")
self.assertEqual(g(s), "sized")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sized")
g.register(c.MutableSet, lambda obj: "mutableset")
self.assertEqual(g(d), "mutablemapping")
self.assertEqual(g(l), "mutablesequence")
self.assertEqual(g(s), "mutableset")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sized")
g.register(c.Mapping, lambda obj: "mapping")
self.assertEqual(g(d), "mutablemapping") # not specific enough
self.assertEqual(g(l), "mutablesequence")
self.assertEqual(g(s), "mutableset")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sized")
g.register(c.Sequence, lambda obj: "sequence")
self.assertEqual(g(d), "mutablemapping")
self.assertEqual(g(l), "mutablesequence")
self.assertEqual(g(s), "mutableset")
self.assertEqual(g(f), "sized")
self.assertEqual(g(t), "sequence")
g.register(c.Set, lambda obj: "set")
self.assertEqual(g(d), "mutablemapping")
self.assertEqual(g(l), "mutablesequence")
self.assertEqual(g(s), "mutableset")
self.assertEqual(g(f), "set")
self.assertEqual(g(t), "sequence")
g.register(dict, lambda obj: "dict")
self.assertEqual(g(d), "dict")
self.assertEqual(g(l), "mutablesequence")
self.assertEqual(g(s), "mutableset")
self.assertEqual(g(f), "set")
self.assertEqual(g(t), "sequence")
g.register(list, lambda obj: "list")
self.assertEqual(g(d), "dict")
self.assertEqual(g(l), "list")
self.assertEqual(g(s), "mutableset")
self.assertEqual(g(f), "set")
self.assertEqual(g(t), "sequence")
g.register(set, lambda obj: "concrete-set")
self.assertEqual(g(d), "dict")
self.assertEqual(g(l), "list")
self.assertEqual(g(s), "concrete-set")
self.assertEqual(g(f), "set")
self.assertEqual(g(t), "sequence")
g.register(frozenset, lambda obj: "frozen-set")
self.assertEqual(g(d), "dict")
self.assertEqual(g(l), "list")
self.assertEqual(g(s), "concrete-set")
self.assertEqual(g(f), "frozen-set")
self.assertEqual(g(t), "sequence")
g.register(tuple, lambda obj: "tuple")
self.assertEqual(g(d), "dict")
self.assertEqual(g(l), "list")
self.assertEqual(g(s), "concrete-set")
self.assertEqual(g(f), "frozen-set")
self.assertEqual(g(t), "tuple")
def test_c3_abc(self):
c = collections.abc
mro = functools._c3_mro
class A(object):
pass
class B(A):
def __len__(self):
return 0 # implies Sized
@c.Container.register
class C(object):
pass
class D(object):
pass # unrelated
class X(D, C, B):
def __call__(self):
pass # implies Callable
expected = [X, c.Callable, D, C, c.Container, B, c.Sized, A, object]
for abcs in permutations([c.Sized, c.Callable, c.Container]):
self.assertEqual(mro(X, abcs=abcs), expected)
# unrelated ABCs don't appear in the resulting MRO
many_abcs = [c.Mapping, c.Sized, c.Callable, c.Container, c.Iterable]
self.assertEqual(mro(X, abcs=many_abcs), expected)
def test_false_meta(self):
# see issue23572
class MetaA(type):
def __len__(self):
return 0
class A(metaclass=MetaA):
pass
class AA(A):
pass
@functools.singledispatch
def fun(a):
return 'base A'
@fun.register(A)
def _(a):
return 'fun A'
aa = AA()
self.assertEqual(fun(aa), 'fun A')
def test_mro_conflicts(self):
c = collections.abc
@functools.singledispatch
def g(arg):
return "base"
class O(c.Sized):
def __len__(self):
return 0
o = O()
self.assertEqual(g(o), "base")
g.register(c.Iterable, lambda arg: "iterable")
g.register(c.Container, lambda arg: "container")
g.register(c.Sized, lambda arg: "sized")
g.register(c.Set, lambda arg: "set")
self.assertEqual(g(o), "sized")
c.Iterable.register(O)
self.assertEqual(g(o), "sized") # because it's explicitly in __mro__
c.Container.register(O)
self.assertEqual(g(o), "sized") # see above: Sized is in __mro__
c.Set.register(O)
self.assertEqual(g(o), "set") # because c.Set is a subclass of
# c.Sized and c.Container
class P:
pass
p = P()
self.assertEqual(g(p), "base")
c.Iterable.register(P)
self.assertEqual(g(p), "iterable")
c.Container.register(P)
with self.assertRaises(RuntimeError) as re_one:
g(p)
self.assertIn(
str(re_one.exception),
(("Ambiguous dispatch: <class 'collections.abc.Container'> "
"or <class 'collections.abc.Iterable'>"),
("Ambiguous dispatch: <class 'collections.abc.Iterable'> "
"or <class 'collections.abc.Container'>")),
)
class Q(c.Sized):
def __len__(self):
return 0
q = Q()
self.assertEqual(g(q), "sized")
c.Iterable.register(Q)
self.assertEqual(g(q), "sized") # because it's explicitly in __mro__
c.Set.register(Q)
self.assertEqual(g(q), "set") # because c.Set is a subclass of
# c.Sized and c.Iterable
@functools.singledispatch
def h(arg):
return "base"
@h.register(c.Sized)
def _(arg):
return "sized"
@h.register(c.Container)
def _(arg):
return "container"
# Even though Sized and Container are explicit bases of MutableMapping,
# this ABC is implicitly registered on defaultdict which makes all of
# MutableMapping's bases implicit as well from defaultdict's
# perspective.
with self.assertRaises(RuntimeError) as re_two:
h(collections.defaultdict(lambda: 0))
self.assertIn(
str(re_two.exception),
(("Ambiguous dispatch: <class 'collections.abc.Container'> "
"or <class 'collections.abc.Sized'>"),
("Ambiguous dispatch: <class 'collections.abc.Sized'> "
"or <class 'collections.abc.Container'>")),
)
class R(collections.defaultdict):
pass
c.MutableSequence.register(R)
@functools.singledispatch
def i(arg):
return "base"
@i.register(c.MutableMapping)
def _(arg):
return "mapping"
@i.register(c.MutableSequence)
def _(arg):
return "sequence"
r = R()
self.assertEqual(i(r), "sequence")
class S:
pass
class T(S, c.Sized):
def __len__(self):
return 0
t = T()
self.assertEqual(h(t), "sized")
c.Container.register(T)
self.assertEqual(h(t), "sized") # because it's explicitly in the MRO
class U:
def __len__(self):
return 0
u = U()
self.assertEqual(h(u), "sized") # implicit Sized subclass inferred
# from the existence of __len__()
c.Container.register(U)
# There is no preference for registered versus inferred ABCs.
with self.assertRaises(RuntimeError) as re_three:
h(u)
self.assertIn(
str(re_three.exception),
(("Ambiguous dispatch: <class 'collections.abc.Container'> "
"or <class 'collections.abc.Sized'>"),
("Ambiguous dispatch: <class 'collections.abc.Sized'> "
"or <class 'collections.abc.Container'>")),
)
class V(c.Sized, S):
def __len__(self):
return 0
@functools.singledispatch
def j(arg):
return "base"
@j.register(S)
def _(arg):
return "s"
@j.register(c.Container)
def _(arg):
return "container"
v = V()
self.assertEqual(j(v), "s")
c.Container.register(V)
self.assertEqual(j(v), "container") # because it ends up right after
# Sized in the MRO
def test_cache_invalidation(self):
from collections import UserDict
import weakref
class TracingDict(UserDict):
def __init__(self, *args, **kwargs):
super(TracingDict, self).__init__(*args, **kwargs)
self.set_ops = []
self.get_ops = []
def __getitem__(self, key):
result = self.data[key]
self.get_ops.append(key)
return result
def __setitem__(self, key, value):
self.set_ops.append(key)
self.data[key] = value
def clear(self):
self.data.clear()
td = TracingDict()
with support.swap_attr(weakref, "WeakKeyDictionary", lambda: td):
c = collections.abc
@functools.singledispatch
def g(arg):
return "base"
d = {}
l = []
self.assertEqual(len(td), 0)
self.assertEqual(g(d), "base")
self.assertEqual(len(td), 1)
self.assertEqual(td.get_ops, [])
self.assertEqual(td.set_ops, [dict])
self.assertEqual(td.data[dict], g.registry[object])
self.assertEqual(g(l), "base")
self.assertEqual(len(td), 2)
self.assertEqual(td.get_ops, [])
self.assertEqual(td.set_ops, [dict, list])
self.assertEqual(td.data[dict], g.registry[object])
self.assertEqual(td.data[list], g.registry[object])
self.assertEqual(td.data[dict], td.data[list])
self.assertEqual(g(l), "base")
self.assertEqual(g(d), "base")
self.assertEqual(td.get_ops, [list, dict])
self.assertEqual(td.set_ops, [dict, list])
g.register(list, lambda arg: "list")
self.assertEqual(td.get_ops, [list, dict])
self.assertEqual(len(td), 0)
self.assertEqual(g(d), "base")
self.assertEqual(len(td), 1)
self.assertEqual(td.get_ops, [list, dict])
self.assertEqual(td.set_ops, [dict, list, dict])
self.assertEqual(td.data[dict],
functools._find_impl(dict, g.registry))
self.assertEqual(g(l), "list")
self.assertEqual(len(td), 2)
self.assertEqual(td.get_ops, [list, dict])
self.assertEqual(td.set_ops, [dict, list, dict, list])
self.assertEqual(td.data[list],
functools._find_impl(list, g.registry))
class X:
pass
c.MutableMapping.register(X) # Will not invalidate the cache,
# not using ABCs yet.
self.assertEqual(g(d), "base")
self.assertEqual(g(l), "list")
self.assertEqual(td.get_ops, [list, dict, dict, list])
self.assertEqual(td.set_ops, [dict, list, dict, list])
g.register(c.Sized, lambda arg: "sized")
self.assertEqual(len(td), 0)
self.assertEqual(g(d), "sized")
self.assertEqual(len(td), 1)
self.assertEqual(td.get_ops, [list, dict, dict, list])
self.assertEqual(td.set_ops, [dict, list, dict, list, dict])
self.assertEqual(g(l), "list")
self.assertEqual(len(td), 2)
self.assertEqual(td.get_ops, [list, dict, dict, list])
self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
self.assertEqual(g(l), "list")
self.assertEqual(g(d), "sized")
self.assertEqual(td.get_ops, [list, dict, dict, list, list, dict])
self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
g.dispatch(list)
g.dispatch(dict)
self.assertEqual(td.get_ops, [list, dict, dict, list, list, dict,
list, dict])
self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
c.MutableSet.register(X) # Will invalidate the cache.
self.assertEqual(len(td), 2) # Stale cache.
self.assertEqual(g(l), "list")
self.assertEqual(len(td), 1)
g.register(c.MutableMapping, lambda arg: "mutablemapping")
self.assertEqual(len(td), 0)
self.assertEqual(g(d), "mutablemapping")
self.assertEqual(len(td), 1)
self.assertEqual(g(l), "list")
self.assertEqual(len(td), 2)
g.register(dict, lambda arg: "dict")
self.assertEqual(g(d), "dict")
self.assertEqual(g(l), "list")
g._clear_cache()
self.assertEqual(len(td), 0)
def test_annotations(self):
@functools.singledispatch
def i(arg):
return "base"
@i.register
def _(arg: collections.abc.Mapping):
return "mapping"
@i.register
def _(arg: "collections.abc.Sequence"):
return "sequence"
self.assertEqual(i(None), "base")
self.assertEqual(i({"a": 1}), "mapping")
self.assertEqual(i([1, 2, 3]), "sequence")
self.assertEqual(i((1, 2, 3)), "sequence")
self.assertEqual(i("str"), "sequence")
# Registering classes as callables doesn't work with annotations,
# you need to pass the type explicitly.
@i.register(str)
class _:
def __init__(self, arg):
self.arg = arg
def __eq__(self, other):
return self.arg == other
self.assertEqual(i("str"), "str")
def test_method_register(self):
class A:
@functools.singledispatchmethod
def t(self, arg):
self.arg = "base"
@t.register(int)
def _(self, arg):
self.arg = "int"
@t.register(str)
def _(self, arg):
self.arg = "str"
a = A()
a.t(0)
self.assertEqual(a.arg, "int")
aa = A()
self.assertFalse(hasattr(aa, 'arg'))
a.t('')
self.assertEqual(a.arg, "str")
aa = A()
self.assertFalse(hasattr(aa, 'arg'))
a.t(0.0)
self.assertEqual(a.arg, "base")
aa = A()
self.assertFalse(hasattr(aa, 'arg'))
def test_staticmethod_register(self):
class A:
@functools.singledispatchmethod
@staticmethod
def t(arg):
return arg
@t.register(int)
@staticmethod
def _(arg):
return isinstance(arg, int)
@t.register(str)
@staticmethod
def _(arg):
return isinstance(arg, str)
a = A()
self.assertTrue(A.t(0))
self.assertTrue(A.t(''))
self.assertEqual(A.t(0.0), 0.0)
def test_slotted_class(self):
class Slot:
__slots__ = ('a', 'b')
@functools.singledispatchmethod
def go(self, item, arg):
pass
@go.register
def _(self, item: int, arg):
return item + arg
s = Slot()
self.assertEqual(s.go(1, 1), 2)
def test_classmethod_slotted_class(self):
class Slot:
__slots__ = ('a', 'b')
@functools.singledispatchmethod
@classmethod
def go(cls, item, arg):
pass
@go.register
@classmethod
def _(cls, item: int, arg):
return item + arg
s = Slot()
self.assertEqual(s.go(1, 1), 2)
self.assertEqual(Slot.go(1, 1), 2)
def test_staticmethod_slotted_class(self):
class A:
__slots__ = ['a']
@functools.singledispatchmethod
@staticmethod
def t(arg):
return arg
@t.register(int)
@staticmethod
def _(arg):
return isinstance(arg, int)
@t.register(str)
@staticmethod
def _(arg):
return isinstance(arg, str)
a = A()
self.assertTrue(A.t(0))
self.assertTrue(A.t(''))
self.assertEqual(A.t(0.0), 0.0)
self.assertTrue(a.t(0))
self.assertTrue(a.t(''))
self.assertEqual(a.t(0.0), 0.0)
def test_assignment_behavior(self):
# see gh-106448
class A:
@functools.singledispatchmethod
def t(arg):
return arg
a = A()
a.t.foo = 'bar'
a2 = A()
with self.assertRaises(AttributeError):
a2.t.foo
def test_classmethod_register(self):
class A:
def __init__(self, arg):
self.arg = arg
@functools.singledispatchmethod
@classmethod
def t(cls, arg):
return cls("base")
@t.register(int)
@classmethod
def _(cls, arg):
return cls("int")
@t.register(str)
@classmethod
def _(cls, arg):
return cls("str")
self.assertEqual(A.t(0).arg, "int")
self.assertEqual(A.t('').arg, "str")
self.assertEqual(A.t(0.0).arg, "base")
def test_callable_register(self):
class A:
def __init__(self, arg):
self.arg = arg
@functools.singledispatchmethod
@classmethod
def t(cls, arg):
return cls("base")
@A.t.register(int)
@classmethod
def _(cls, arg):
return cls("int")
@A.t.register(str)
@classmethod
def _(cls, arg):
return cls("str")
self.assertEqual(A.t(0).arg, "int")
self.assertEqual(A.t('').arg, "str")
self.assertEqual(A.t(0.0).arg, "base")
def test_abstractmethod_register(self):
class Abstract(metaclass=abc.ABCMeta):
@functools.singledispatchmethod
@abc.abstractmethod
def add(self, x, y):
pass
self.assertTrue(Abstract.add.__isabstractmethod__)
self.assertTrue(Abstract.__dict__['add'].__isabstractmethod__)
with self.assertRaises(TypeError):
Abstract()
def test_type_ann_register(self):
class A:
@functools.singledispatchmethod
def t(self, arg):
return "base"
@t.register
def _(self, arg: int):
return "int"
@t.register
def _(self, arg: str):
return "str"
a = A()
self.assertEqual(a.t(0), "int")
self.assertEqual(a.t(''), "str")
self.assertEqual(a.t(0.0), "base")
def test_staticmethod_type_ann_register(self):
class A:
@functools.singledispatchmethod
@staticmethod
def t(arg):
return arg
@t.register
@staticmethod
def _(arg: int):
return isinstance(arg, int)
@t.register
@staticmethod
def _(arg: str):
return isinstance(arg, str)
a = A()
self.assertTrue(A.t(0))
self.assertTrue(A.t(''))
self.assertEqual(A.t(0.0), 0.0)
def test_classmethod_type_ann_register(self):
class A:
def __init__(self, arg):
self.arg = arg
@functools.singledispatchmethod
@classmethod
def t(cls, arg):
return cls("base")
@t.register
@classmethod
def _(cls, arg: int):
return cls("int")
@t.register
@classmethod
def _(cls, arg: str):
return cls("str")
self.assertEqual(A.t(0).arg, "int")
self.assertEqual(A.t('').arg, "str")
self.assertEqual(A.t(0.0).arg, "base")
def test_method_wrapping_attributes(self):
class A:
@functools.singledispatchmethod
def func(self, arg: int) -> str:
"""My function docstring"""
return str(arg)
@functools.singledispatchmethod
@classmethod
def cls_func(cls, arg: int) -> str:
"""My function docstring"""
return str(arg)
@functools.singledispatchmethod
@staticmethod
def static_func(arg: int) -> str:
"""My function docstring"""
return str(arg)
for meth in (
A.func,
A().func,
A.cls_func,
A().cls_func,
A.static_func,
A().static_func
):
with self.subTest(meth=meth):
self.assertEqual(meth.__doc__, 'My function docstring')
self.assertEqual(meth.__annotations__['arg'], int)
self.assertEqual(A.func.__name__, 'func')
self.assertEqual(A().func.__name__, 'func')
self.assertEqual(A.cls_func.__name__, 'cls_func')
self.assertEqual(A().cls_func.__name__, 'cls_func')
self.assertEqual(A.static_func.__name__, 'static_func')
self.assertEqual(A().static_func.__name__, 'static_func')
def test_double_wrapped_methods(self):
def classmethod_friendly_decorator(func):
wrapped = func.__func__
@classmethod
@functools.wraps(wrapped)
def wrapper(*args, **kwargs):
return wrapped(*args, **kwargs)
return wrapper
class WithoutSingleDispatch:
@classmethod
@contextlib.contextmanager
def cls_context_manager(cls, arg: int) -> str:
try:
yield str(arg)
finally:
return 'Done'
@classmethod_friendly_decorator
@classmethod
def decorated_classmethod(cls, arg: int) -> str:
return str(arg)
class WithSingleDispatch:
@functools.singledispatchmethod
@classmethod
@contextlib.contextmanager
def cls_context_manager(cls, arg: int) -> str:
"""My function docstring"""
try:
yield str(arg)
finally:
return 'Done'
@functools.singledispatchmethod
@classmethod_friendly_decorator
@classmethod
def decorated_classmethod(cls, arg: int) -> str:
"""My function docstring"""
return str(arg)
# These are sanity checks
# to test the test itself is working as expected
with WithoutSingleDispatch.cls_context_manager(5) as foo:
without_single_dispatch_foo = foo
with WithSingleDispatch.cls_context_manager(5) as foo:
single_dispatch_foo = foo
self.assertEqual(without_single_dispatch_foo, single_dispatch_foo)
self.assertEqual(single_dispatch_foo, '5')
self.assertEqual(
WithoutSingleDispatch.decorated_classmethod(5),
WithSingleDispatch.decorated_classmethod(5)
)
self.assertEqual(WithSingleDispatch.decorated_classmethod(5), '5')
# Behavioural checks now follow
for method_name in ('cls_context_manager', 'decorated_classmethod'):
with self.subTest(method=method_name):
self.assertEqual(
getattr(WithSingleDispatch, method_name).__name__,
getattr(WithoutSingleDispatch, method_name).__name__
)
self.assertEqual(
getattr(WithSingleDispatch(), method_name).__name__,
getattr(WithoutSingleDispatch(), method_name).__name__
)
for meth in (
WithSingleDispatch.cls_context_manager,
WithSingleDispatch().cls_context_manager,
WithSingleDispatch.decorated_classmethod,
WithSingleDispatch().decorated_classmethod
):
with self.subTest(meth=meth):
self.assertEqual(meth.__doc__, 'My function docstring')
self.assertEqual(meth.__annotations__['arg'], int)
self.assertEqual(
WithSingleDispatch.cls_context_manager.__name__,
'cls_context_manager'
)
self.assertEqual(
WithSingleDispatch().cls_context_manager.__name__,
'cls_context_manager'
)
self.assertEqual(
WithSingleDispatch.decorated_classmethod.__name__,
'decorated_classmethod'
)
self.assertEqual(
WithSingleDispatch().decorated_classmethod.__name__,
'decorated_classmethod'
)
def test_invalid_registrations(self):
msg_prefix = "Invalid first argument to `register()`: "
msg_suffix = (
". Use either `@register(some_class)` or plain `@register` on an "
"annotated function."
)
@functools.singledispatch
def i(arg):
return "base"
with self.assertRaises(TypeError) as exc:
@i.register(42)
def _(arg):
return "I annotated with a non-type"
self.assertTrue(str(exc.exception).startswith(msg_prefix + "42"))
self.assertTrue(str(exc.exception).endswith(msg_suffix))
with self.assertRaises(TypeError) as exc:
@i.register
def _(arg):
return "I forgot to annotate"
self.assertTrue(str(exc.exception).startswith(msg_prefix +
"<function TestSingleDispatch.test_invalid_registrations.<locals>._"
))
self.assertTrue(str(exc.exception).endswith(msg_suffix))
with self.assertRaises(TypeError) as exc:
@i.register
def _(arg: typing.Iterable[str]):
# At runtime, dispatching on generics is impossible.
# When registering implementations with singledispatch, avoid
# types from `typing`. Instead, annotate with regular types
# or ABCs.
return "I annotated with a generic collection"
self.assertTrue(str(exc.exception).startswith(
"Invalid annotation for 'arg'."
))
self.assertTrue(str(exc.exception).endswith(
'typing.Iterable[str] is not a class.'
))
with self.assertRaises(TypeError) as exc:
@i.register
def _(arg: typing.Union[int, typing.Iterable[str]]):
return "Invalid Union"
self.assertTrue(str(exc.exception).startswith(
"Invalid annotation for 'arg'."
))
self.assertTrue(str(exc.exception).endswith(
'typing.Union[int, typing.Iterable[str]] not all arguments are classes.'
))
def test_invalid_positional_argument(self):
@functools.singledispatch
def f(*args):
pass
msg = 'f requires at least 1 positional argument'
with self.assertRaisesRegex(TypeError, msg):
f()
def test_union(self):
@functools.singledispatch
def f(arg):
return "default"
@f.register
def _(arg: typing.Union[str, bytes]):
return "typing.Union"
@f.register
def _(arg: int | float):
return "types.UnionType"
self.assertEqual(f([]), "default")
self.assertEqual(f(""), "typing.Union")
self.assertEqual(f(b""), "typing.Union")
self.assertEqual(f(1), "types.UnionType")
self.assertEqual(f(1.0), "types.UnionType")
def test_union_conflict(self):
@functools.singledispatch
def f(arg):
return "default"
@f.register
def _(arg: typing.Union[str, bytes]):
return "typing.Union"
@f.register
def _(arg: int | str):
return "types.UnionType"
self.assertEqual(f([]), "default")
self.assertEqual(f(""), "types.UnionType") # last one wins
self.assertEqual(f(b""), "typing.Union")
self.assertEqual(f(1), "types.UnionType")
def test_union_None(self):
@functools.singledispatch
def typing_union(arg):
return "default"
@typing_union.register
def _(arg: typing.Union[str, None]):
return "typing.Union"
self.assertEqual(typing_union(1), "default")
self.assertEqual(typing_union(""), "typing.Union")
self.assertEqual(typing_union(None), "typing.Union")
@functools.singledispatch
def types_union(arg):
return "default"
@types_union.register
def _(arg: int | None):
return "types.UnionType"
self.assertEqual(types_union(""), "default")
self.assertEqual(types_union(1), "types.UnionType")
self.assertEqual(types_union(None), "types.UnionType")
def test_register_genericalias(self):
@functools.singledispatch
def f(arg):
return "default"
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(list[int], lambda arg: "types.GenericAlias")
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(typing.List[int], lambda arg: "typing.GenericAlias")
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(list[int] | str, lambda arg: "types.UnionTypes(types.GenericAlias)")
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(typing.List[float] | bytes, lambda arg: "typing.Union[typing.GenericAlias]")
self.assertEqual(f([1]), "default")
self.assertEqual(f([1.0]), "default")
self.assertEqual(f(""), "default")
self.assertEqual(f(b""), "default")
def test_register_genericalias_decorator(self):
@functools.singledispatch
def f(arg):
return "default"
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(list[int])
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(typing.List[int])
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(list[int] | str)
with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
f.register(typing.List[int] | str)
def test_register_genericalias_annotation(self):
@functools.singledispatch
def f(arg):
return "default"
with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
@f.register
def _(arg: list[int]):
return "types.GenericAlias"
with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
@f.register
def _(arg: typing.List[float]):
return "typing.GenericAlias"
with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
@f.register
def _(arg: list[int] | str):
return "types.UnionType(types.GenericAlias)"
with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
@f.register
def _(arg: typing.List[float] | bytes):
return "typing.Union[typing.GenericAlias]"
self.assertEqual(f([1]), "default")
self.assertEqual(f([1.0]), "default")
self.assertEqual(f(""), "default")
self.assertEqual(f(b""), "default")
class CachedCostItem:
_cost = 1
def __init__(self):
self.lock = py_functools.RLock()
@py_functools.cached_property
def cost(self):
"""The cost of the item."""
with self.lock:
self._cost += 1
return self._cost
class OptionallyCachedCostItem:
_cost = 1
def get_cost(self):
"""The cost of the item."""
self._cost += 1
return self._cost
cached_cost = py_functools.cached_property(get_cost)
class CachedCostItemWithSlots:
__slots__ = ('_cost')
def __init__(self):
self._cost = 1
@py_functools.cached_property
def cost(self):
raise RuntimeError('never called, slots not supported')
class TestCachedProperty(unittest.TestCase):
def test_cached(self):
item = CachedCostItem()
self.assertEqual(item.cost, 2)
self.assertEqual(item.cost, 2) # not 3
def test_cached_attribute_name_differs_from_func_name(self):
item = OptionallyCachedCostItem()
self.assertEqual(item.get_cost(), 2)
self.assertEqual(item.cached_cost, 3)
self.assertEqual(item.get_cost(), 4)
self.assertEqual(item.cached_cost, 3)
def test_object_with_slots(self):
item = CachedCostItemWithSlots()
with self.assertRaisesRegex(
TypeError,
"No '__dict__' attribute on 'CachedCostItemWithSlots' instance to cache 'cost' property.",
):
item.cost
def test_immutable_dict(self):
class MyMeta(type):
@py_functools.cached_property
def prop(self):
return True
class MyClass(metaclass=MyMeta):
pass
with self.assertRaisesRegex(
TypeError,
"The '__dict__' attribute on 'MyMeta' instance does not support item assignment for caching 'prop' property.",
):
MyClass.prop
def test_reuse_different_names(self):
"""Disallow this case because decorated function a would not be cached."""
with self.assertRaises(TypeError) as ctx:
class ReusedCachedProperty:
@py_functools.cached_property
def a(self):
pass
b = a
self.assertEqual(
str(ctx.exception),
str(TypeError("Cannot assign the same cached_property to two different names ('a' and 'b')."))
)
def test_reuse_same_name(self):
"""Reusing a cached_property on different classes under the same name is OK."""
counter = 0
@py_functools.cached_property
def _cp(_self):
nonlocal counter
counter += 1
return counter
class A:
cp = _cp
class B:
cp = _cp
a = A()
b = B()
self.assertEqual(a.cp, 1)
self.assertEqual(b.cp, 2)
self.assertEqual(a.cp, 1)
def test_set_name_not_called(self):
cp = py_functools.cached_property(lambda s: None)
class Foo:
pass
Foo.cp = cp
with self.assertRaisesRegex(
TypeError,
"Cannot use cached_property instance without calling __set_name__ on it.",
):
Foo().cp
def test_access_from_class(self):
self.assertIsInstance(CachedCostItem.cost, py_functools.cached_property)
def test_doc(self):
self.assertEqual(CachedCostItem.cost.__doc__, "The cost of the item.")
def test_module(self):
self.assertEqual(CachedCostItem.cost.__module__, CachedCostItem.__module__)
def test_subclass_with___set__(self):
"""Caching still works for a subclass defining __set__."""
class readonly_cached_property(py_functools.cached_property):
def __set__(self, obj, value):
raise AttributeError("read only property")
class Test:
def __init__(self, prop):
self._prop = prop
@readonly_cached_property
def prop(self):
return self._prop
t = Test(1)
self.assertEqual(t.prop, 1)
t._prop = 999
self.assertEqual(t.prop, 1)
if __name__ == '__main__':
unittest.main()
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