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""" Checks that reversed() receive proper argument """
# pylint: disable=missing-docstring
# pylint: disable=too-few-public-methods
from collections import deque, OrderedDict
from enum import IntEnum
class GoodReversed:
""" Implements __reversed__ """
def __reversed__(self):
return [1, 2, 3]
class SecondGoodReversed:
""" Implements __len__ and __getitem__ """
def __len__(self):
return 3
def __getitem__(self, index):
return index
class BadReversed:
""" implements only len() """
def __len__(self):
return 3
class SecondBadReversed:
""" implements only __getitem__ """
def __getitem__(self, index):
return index
def uninferable(seq):
""" This can't be inferred at this moment,
make sure we don't have a false positive.
"""
return reversed(seq)
def test(path):
""" test function """
seq = reversed() # No argument given
seq = reversed(None) # [bad-reversed-sequence]
seq = reversed([1, 2, 3])
seq = reversed((1, 2, 3))
seq = reversed(set()) # [bad-reversed-sequence]
seq = reversed(iter([1, 2, 3])) # [bad-reversed-sequence]
seq = reversed(GoodReversed())
seq = reversed(SecondGoodReversed())
seq = reversed(BadReversed()) # [bad-reversed-sequence]
seq = reversed(SecondBadReversed()) # [bad-reversed-sequence]
seq = reversed(range(100))
seq = reversed(lambda: None) # [bad-reversed-sequence]
seq = reversed(deque([]))
seq = reversed("123")
seq = uninferable([1, 2, 3])
seq = reversed(path.split("/"))
return seq
def test_dict_ancestor_and_reversed():
"""Don't emit for subclasses of dict, with __reversed__ implemented."""
class Child(dict):
def __reversed__(self):
return reversed(range(10))
seq = reversed(OrderedDict())
return reversed(Child()), seq
def test_dont_emit_for_reversing_enums():
"""Don't emit when reversing enum classes"""
class Color(IntEnum):
RED = 1
GREEN = 2
BLUE = 3
for color in reversed(Color):
yield color
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