add delete and size tests

Author: amejiarosario

src/linked-list/linkedlist.js

@@ -51,15 +51,18 @@ class LinkedList {
   delete(data) {
     let n = this.head;
 
+    // remove from head
     if(n.data === data) {
       this.head = this.head.next;
+      this.length--;
       return;
     }
 
     // iterate
     while(n.next){
       if(n.next.data === data) {
         n.next = n.next.next;
+        this.length--;
         return;
       }
       n = n.next;

src/linked-list/linkedlist.spec.js

@@ -1,29 +1,88 @@
 const LinkedList = require('./linkedlist');
 
 describe('LinkedList', function () {
+  let list;
 
   describe('.addLast', function () {
-
-    it('should add elements to the tail and count size', function () {
-      const list = new LinkedList();
+    beforeEach(function () {
+      list = new LinkedList();
       list.addLast(1);
       list.addLast(2);
       list.addLast(3);
       list.addLast(4);
+    });
 
+    it('should add elements to the tail and count size', function () {
       expect(list.toString()).toEqual('1 -> 2 -> 3 -> 4');
+    });
+
+    it('should have a size of 4', function () {
       expect(list.size()).toBe(4);
     });
+  });
 
-    it('should add elements to the head and count size', function () {
-      const list = new LinkedList();
+  describe('.addFirst', function () {
+    beforeEach(function () {
+      list = new LinkedList();
       list.addFirst(1);
       list.addFirst(2);
       list.addFirst(3);
       list.addFirst(4);
+    });
 
+    it('should add elements to the tail and count size', function () {
       expect(list.toString()).toEqual('4 -> 3 -> 2 -> 1');
+    });
+
+    it('should have a size of 4', function () {
       expect(list.size()).toBe(4);
-    })
+    });
   });
+
+  describe('.add (addFirst)', function () {
+    beforeEach(function () {
+      list = new LinkedList();
+      list.add(1);
+      list.add(2);
+      list.add(3);
+      list.add(4);
+    });
+
+    it('should add elements to the tail and count size', function () {
+      expect(list.toString()).toEqual('4 -> 3 -> 2 -> 1');
+    });
+
+    it('should have a size of 4', function () {
+      expect(list.size()).toBe(4);
+    });
+  });
+
+  describe('.delete', function () {
+    beforeEach(function () {
+      list = new LinkedList();
+      list.add(1);
+      list.add(2);
+      list.add(3);
+      list.add(4);
+    });
+
+    it('should start with size of 3 after deleting one', function () {
+      list.delete(4);
+      expect(list.size()).toBe(3);
+    });
+
+    it('should have a size of 4', function () {
+      list.delete(4);
+      list.delete(2);
+      list.delete(1);
+      list.delete(3);
+      expect(list.size()).toBe(0);
+    });
+
+    it('should not change if element not found', function () {
+      list.delete(7);
+      expect(list.size()).toBe(4);
+    });
+  });
+
 });