def test_insert_at_tail__empty_list__ok(self):
alist = LinkedList()
assert alist.is_empty() is True
assert alist.get_head() is None
data = 1
alist.insert_at_tail(data)
assert alist.is_empty() is False
assert alist.get_head().data == data
assert str(alist) == f"{data} -> None"
def test_insert_at_tail__non_empty_list__ok(self):
alist = LinkedList(Node("1"))
assert alist.is_empty() is False
assert alist.get_head() is not None
data = 2
alist.insert_at_tail(data)
assert alist.is_empty() is False
assert str(alist) == f"1 -> {data} -> None"
data = 3
alist.insert_at_tail(data)
assert alist.is_empty() is False
assert str(alist) == f"1 -> 2 -> {data} -> None"