len() funktion, fix pop() funktion, assertions in starten.py

linked-lists/starten.py

@@ -1,15 +1,26 @@
 from linked_list import LinkedList
 
 list = LinkedList()
+assert list.len() == 0
 list.push(123)
+assert list.len() == 1
 list.push(456)
+assert list.len() == 2
 list.push(789)
-# list.insert(00000, 1)
+assert list.len() == 3
+list.insert(-10, 1)
 list.print()
+assert list.len() == 4
+print(list.len())
 
 print(list.pop())
+assert list.len() == 3
 print(list.pop())
+assert list.len() == 2
 print(list.pop())
+assert list.len() == 1
+print(list.pop())
+assert list.len() == 0
 
 
 # node3 = Node(333)