Viewing file:  test_contains.py (3.35 KB) -rw-r--r--
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from collections import deque
import unittest
from test.support import NEVER_EQ
class base_set:
def __init__(self, el):
self.el = el
class myset(base_set):
def __contains__(self, el):
return self.el == el
class seq(base_set):
def __getitem__(self, n):
return [self.el][n]
class TestContains(unittest.TestCase):
def test_common_tests(self):
a = base_set(1)
b = myset(1)
c = seq(1)
self.assertIn(1, b)
self.assertNotIn(0, b)
self.assertIn(1, c)
self.assertNotIn(0, c)
self.assertRaises(TypeError, lambda: 1 in a)
self.assertRaises(TypeError, lambda: 1 not in a)
# test char in string
self.assertIn('c', 'abc')
self.assertNotIn('d', 'abc')
self.assertIn('', '')
self.assertIn('', 'abc')
self.assertRaises(TypeError, lambda: None in 'abc')
def test_builtin_sequence_types(self):
# a collection of tests on builtin sequence types
a = range(10)
for i in a:
self.assertIn(i, a)
self.assertNotIn(16, a)
self.assertNotIn(a, a)
a = tuple(a)
for i in a:
self.assertIn(i, a)
self.assertNotIn(16, a)
self.assertNotIn(a, a)
class Deviant1:
"""Behaves strangely when compared
This class is designed to make sure that the contains code
works when the list is modified during the check.
"""
aList = list(range(15))
def __eq__(self, other):
if other == 12:
self.aList.remove(12)
self.aList.remove(13)
self.aList.remove(14)
return 0
self.assertNotIn(Deviant1(), Deviant1.aList)
def test_nonreflexive(self):
# containment and equality tests involving elements that are
# not necessarily equal to themselves
values = float('nan'), 1, None, 'abc', NEVER_EQ
constructors = list, tuple, dict.fromkeys, set, frozenset, deque
for constructor in constructors:
container = constructor(values)
for elem in container:
self.assertIn(elem, container)
self.assertTrue(container == constructor(values))
self.assertTrue(container == container)
def test_block_fallback(self):
# blocking fallback with __contains__ = None
class ByContains(object):
def __contains__(self, other):
return False
c = ByContains()
class BlockContains(ByContains):
"""Is not a container
This class is a perfectly good iterable (as tested by
list(bc)), as well as inheriting from a perfectly good
container, but __contains__ = None prevents the usual
fallback to iteration in the container protocol. That
is, normally, 0 in bc would fall back to the equivalent
of any(x==0 for x in bc), but here it's blocked from
doing so.
"""
def __iter__(self):
while False:
yield None
__contains__ = None
bc = BlockContains()
self.assertFalse(0 in c)
self.assertFalse(0 in list(bc))
self.assertRaises(TypeError, lambda: 0 in bc)
if __name__ == '__main__':
unittest.main()
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