def test_length_add(self):
s = CustomSet()
s.add('a')
s.add('b')
s.add('c')
assert s.length() == 3
assert s.size == 3
def test_delete(self):
s = CustomSet()
s.add('a')
s.add('b')
s.add('cee')
s.remove('cee')
assert s.length() == 2
assert s.size == 2
def test_init(self):
s = CustomSet()
assert s.size == 0
assert s.length() == 0
def test_init_with_list(self):
s = CustomSet(['a','b','c'])
assert s.length() == 3