mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-04 00:48:58 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

Add collections.Reversible. Patch by Ivan Levkivskyi. Fixes issue #25987.

Browse source
This commit is contained in:
Guido van Rossum 2016-04-04 10:59:29 -07:00
parent 9ad764601b
commit 16ca06b8cb
5 changed files with 61 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

31
Lib/test/test_collections.py
View file

@ -20,7 +20,7 @@ from collections import UserDict, UserString, UserList
from collections import ChainMap
from collections import deque
from collections.abc import Awaitable, Coroutine, AsyncIterator, AsyncIterable
from collections.abc import Hashable, Iterable, Iterator, Generator
from collections.abc import Hashable, Iterable, Iterator, Generator, Reversible
from collections.abc import Sized, Container, Callable
from collections.abc import Set, MutableSet
from collections.abc import Mapping, MutableMapping, KeysView, ItemsView
@ -689,6 +689,31 @@ class TestOneTrickPonyABCs(ABCTestCase):
self.validate_abstract_methods(Iterable, '__iter__')
self.validate_isinstance(Iterable, '__iter__')
def test_Reversible(self):
# Check some non-reversibles
non_samples = [None, 42, 3.14, 1j, dict(), set(), frozenset()]
for x in non_samples:
self.assertNotIsInstance(x, Reversible)
self.assertFalse(issubclass(type(x), Reversible), repr(type(x)))
# Check some reversibles
samples = [tuple(), list()]
for x in samples:
self.assertIsInstance(x, Reversible)
self.assertTrue(issubclass(type(x), Reversible), repr(type(x)))
# Check also Mapping, MutableMapping, and Sequence
self.assertTrue(issubclass(Sequence, Reversible), repr(Sequence))
self.assertFalse(issubclass(Mapping, Reversible), repr(Mapping))
self.assertFalse(issubclass(MutableMapping, Reversible), repr(MutableMapping))
# Check direct subclassing
class R(Reversible):
def __iter__(self):
return iter(list())
def __reversed__(self):
return iter(list())
self.assertEqual(list(reversed(R())), [])
self.assertFalse(issubclass(float, R))
self.validate_abstract_methods(Reversible, '__reversed__', '__iter__')
def test_Iterator(self):
non_samples = [None, 42, 3.14, 1j, b"", "", (), [], {}, set()]
for x in non_samples:
@ -842,14 +867,14 @@ class TestOneTrickPonyABCs(ABCTestCase):
self.validate_isinstance(Callable, '__call__')
def test_direct_subclassing(self):
for B in Hashable, Iterable, Iterator, Sized, Container, Callable:
for B in Hashable, Iterable, Iterator, Reversible, Sized, Container, Callable:
class C(B):
pass
self.assertTrue(issubclass(C, B))
self.assertFalse(issubclass(int, C))
def test_registration(self):
for B in Hashable, Iterable, Iterator, Sized, Container, Callable:
for B in Hashable, Iterable, Iterator, Reversible, Sized, Container, Callable:
class C:
__hash__ = None # Make sure it isn't hashable by default
self.assertFalse(issubclass(C, B), B.__name__)