def test_linked_list_insert_before_middle():
ll = LinkedList()
ll.append('a')
ll.append('c')
ll.insertBefore('c', 'b')
actual = str(ll)
expected = "{ a } -> { b } -> { c } -> NULL"
assert actual == expected
def test_insertBefore():
node = Node(6)
linked1 = LinkedList(node)
linked1.insert(5)
linked1.insert(4)
linked1.insertBefore(5,9)
actual = str(linked1)
expected = '{4} -> {9} -> {5} -> {6} -> Null'
assert actual == expected
