def test_add(self):
ht = HashedSet()
assert ht._size() == 0
ht.add('A')
assert ht._size() == 1
assert ht.has('A') == True
ht.add('B')
assert ht._size() == 2
assert ht.has('B') == True
def test_size(self):
ht = HashedSet()
assert ht._size() == 0
ht.add('A')
assert ht._size() == 1
ht.add('B')
assert ht._size() == 2
ht.remove('A')
assert ht._size() == 1
ht.remove('B')
assert ht._size() == 0