def test_hashability():
"""Test __hash__ for bags.
Since bag is mutable and frozenbag is hashable, the second
should be usable for dictionary keys and the second should raise a key
or value error when used as a key or placed in a set.
"""
a = bag([1, 2, 3]) # Mutable multiset.
b = frozenbag([1, 1, 2, 3]) # prototypical frozen multiset.
c = frozenbag([4, 4, 5, 5, b, b]) # make sure we can nest them
d = frozenbag([4, frozenbag([1, 3, 2, 1]), 4, 5, b, 5])
# c and d are the same; make sure nothing weird happens to hashes.
assert c == d # Make sure both constructions work.
dic = {
b: 3,
d: 5,
d: 7,
}
assert len(dic) == 2 # Make sure no duplicates in dictionary.
# Make sure TypeErrors are raised when using mutable bags for keys.
with pytest.raises(TypeError):
dic[a] = 4
with pytest.raises(TypeError):
frozenbag([a, 1])
with pytest.raises(TypeError):
bag([a, 1])
# test commutativity of bag instantiation.
assert bag([4, 4, 5, 5, c]) == bag([4, 5, d, 4, 5])
def test_hashability():
"""Test __hash__ for bags.
Since bag is mutable and frozenbag is hashable, the second
should be usable for dictionary keys and the second should raise a key
or value error when used as a key or placed in a set.
"""
a = bag([1, 2, 3]) # Mutable multiset.
b = frozenbag([1, 1, 2, 3]) # prototypical frozen multiset.
c = frozenbag([4, 4, 5, 5, b, b]) # make sure we can nest them
d = frozenbag([4, frozenbag([1, 3, 2, 1]), 4, 5, b, 5])
# c and d are the same; make sure nothing weird happens to hashes.
assert c == d # Make sure both constructions work.
dic = {
b: 3,
d: 5,
d: 7,
}
assert len(dic) == 2 # Make sure no duplicates in dictionary.
# Make sure TypeErrors are raised when using mutable bags for keys.
with pytest.raises(TypeError):
dic[a] = 4
with pytest.raises(TypeError):
frozenbag([a, 1])
with pytest.raises(TypeError):
bag([a, 1])
# test commutativity of bag instantiation.
assert bag([4, 4, 5, 5, c]) == bag([4, 5, d, 4, 5])
def test_hash():
"""Test __hash__ vs an empty bag."""
bag_with_empty_tuple = frozenbag([()])
assert not hash(frozenbag()) == hash(bag_with_empty_tuple)
assert not hash(frozenbag()) == hash(frozenbag((0, )))
assert not hash(frozenbag('a')) == hash(frozenbag(('aa')))
assert not hash(frozenbag('a')) == hash(frozenbag(('aaa')))
assert not hash(frozenbag('a')) == hash(frozenbag(('aaaa')))
assert not hash(frozenbag('a')) == hash(frozenbag(('aaaaa')))
assert hash(frozenbag('ba')) == hash(frozenbag(('ab')))
assert hash(frozenbag('badce')) == hash(frozenbag(('dbeac')))
def test_hash():
"""Test __hash__ vs an empty bag."""
bag_with_empty_tuple = frozenbag([()])
assert not hash(frozenbag()) == hash(bag_with_empty_tuple)
assert not hash(frozenbag()) == hash(frozenbag((0,)))
assert not hash(frozenbag('a')) == hash(frozenbag(('aa')))
assert not hash(frozenbag('a')) == hash(frozenbag(('aaa')))
assert not hash(frozenbag('a')) == hash(frozenbag(('aaaa')))
assert not hash(frozenbag('a')) == hash(frozenbag(('aaaaa')))
assert hash(frozenbag('ba')) == hash(frozenbag(('ab')))
assert hash(frozenbag('badce')) == hash(frozenbag(('dbeac')))