def test_remove():
bag = Bag()
bag.add(1, 10)
bag.add(2, 20)
bag.add(1, 10)
bag.add(1, 20)
pairs = bag.find_all(1)
assert bag.remove(1) in pairs
assert len(bag.find_all(1)) == len(pairs) - 1
assert bag.remove(2) == (2, 20)
assert bag.remove(2) == None
def test_find_all():
bag = Bag()
bag.add(1, 10)
bag.add(2, 20)
bag.add(1, 10)
bag.add(1, 20)
pairs = bag.find_all(1)
assert (1, 10) in pairs
assert pairs.count((1, 10)) == 2
assert bag.find_all(10) == []
assert bag.find_all(2) == [(2, 20)]
def test_find():
bag = Bag()
bag.add(1, 10)
bag.add(2, 20)
bag.add(1, 10)
bag.add(1, 20)
assert bag.find(1) in bag.find_all(1)
assert bag.find(2) == (2, 20)
assert bag.find(10) == None
