From 16ca06b8cb2426b540fdab75914d7cd0f715b7f0 Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Mon, 4 Apr 2016 10:59:29 -0700 Subject: Add collections.Reversible. Patch by Ivan Levkivskyi. Fixes issue #25987. --- Lib/test/test_collections.py | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) (limited to 'Lib/test/test_collections.py') diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py index 4c32e094f9..42024628c5 100644 --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -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__) -- cgit v1.2.1