def test_prepend(self):
ll = LinkedList()
ll.prepend('C')
assert ll.head.data == 'C'
assert ll.tail.data == 'C'
assert ll.as_list() == ['C']
ll.prepend('B')
assert ll.head.data == 'B'
assert ll.tail.data == 'C'
assert ll.as_list() == ['B', 'C']
ll.prepend('A')
assert ll.head.data == 'A'
assert ll.tail.data == 'C'
assert ll.as_list() == ['A', 'B', 'C']
def test_init_with_list(self):
ll = LinkedList(['A', 'B', 'C'])
assert ll.head.data == 'A'
assert ll.tail.data == 'C'
assert ll.as_list() == ['A', 'B', 'C']
assert ll.is_empty() is False
def test_init(self):
ll = LinkedList()
assert ll.head is None
assert ll.tail is None
assert ll.as_list() == []
assert ll.is_empty() is True