diff --git a/LList.zig b/LList.zig
index 09a3726..82c27df 100644
--- a/LList.zig
+++ b/LList.zig
@@ -1,19 +1,23 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
+const expect = std.testing.expect;
+const testingAllocator = std.testing.allocator;
+
 
 pub fn LList(comptime T: type) type {
     return struct {
         const Self = @This();
         first: ?*Node(T),
         alloc: Allocator,
+        counter: u64,
 
 
         pub fn init(this: *Self, allocator: Allocator) !void { 
             this.alloc = allocator;
             this.first = null;
+            this.counter = 0;
         }
 
-
         pub fn deinit(this: *Self) !void {
 
             //? If there is no created Node
@@ -25,6 +29,10 @@ pub fn LList(comptime T: type) type {
             var currentNode: *Node(T) = this.first orelse unreachable;
 
             while (true) {
+                if (currentNode.next == null){
+                    break;
+                }
+
                 const nextNode = currentNode.next orelse unreachable;
                 var breakNext = false;
 
@@ -41,6 +49,7 @@ pub fn LList(comptime T: type) type {
                 }
             }
             try currentNode.deinit();
+            this.counter = 0;
         }
 
 
@@ -50,30 +59,16 @@ pub fn LList(comptime T: type) type {
             try newNode.init(this.alloc, value, this.first);
             this.first = newNode;
 
+            this.counter = this.counter + 1;
+
             return newNode;
         }
 
+        pub fn size(this: *Self) !u64{
 
-        pub fn printList(this: *Self) !void {
-            const writer = std.io.getStdOut().writer();
-
-            if (this.first == null) {
-                try writer.print("List is empty \n", .{});
-                return;
-            }
-
-            var currentNode: *Node(T) = this.first orelse unreachable;
-
-            while (true) {
-                try writer.print("{any}\n", .{currentNode.value.*});
-                currentNode = currentNode.next orelse unreachable;
-
-                if (currentNode.next == null) {
-                    break;
-                }
-            }
-            try writer.print("{any}\n", .{currentNode.value.*});
+            return this.counter;
         }
+
     };
 }
 
@@ -82,7 +77,7 @@ pub fn Node(comptime T: type) type {
     return struct {
         const Self = @This();
         alloc: Allocator,
-        next: ?*Self, //? Nächste Node in der Liste
+        next: ?*Self, 
         value: *T,
 
         pub fn init(this: *Self, allocator: Allocator, value: T, next: ?*Self) !void {
@@ -100,25 +95,35 @@ pub fn Node(comptime T: type) type {
         }
 
 
-        pub fn printNode(this: *Self) !void {
-            const writer = std.io.getStdOut().writer();
-            try writer.print("Value: {any} \n", .{this.value});
-        }
     };
 }
 
-pub fn main() !void {
-    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
-    const allocator = gpa.allocator();
+test "leaks" {
 
     var testList: LList(u64) = undefined;
-    try testList.init(allocator);
+    try testList.init(testingAllocator);
+
+    _ = try testList.add(1);
+    _ = try testList.add(2);
+
+
+    try testList.deinit();
+    
+}
+
+
+test "size" {
+
+    var testList: LList(u64) = undefined;
+    try testList.init(testingAllocator);
+
     _ = try testList.add(1);
     _ = try testList.add(2);
     _ = try testList.add(3);
     _ = try testList.add(4);
 
-    try testList.printList();
+    try expect(try testList.size() == 4);
 
     try testList.deinit();
+    
 }