def test_insert_before_first():
    list = LinkedList()
    list.append(1)
    list.append(2)
    list.append(3)
    list.insertBefore(1, 1.5)
    assert list.head.value == 1.5
def test_insert_before_middle():
    list = LinkedList()
    list.append(1)
    list.append(2)
    list.append(3)
    list.insertBefore(2, 2.5)
    assert list.head.next.value == 2.5