text: var LinkedList = require('./linked-list');
  
  describe('LinkedList', function () {
    it('push/pop', function () {
      var list = new LinkedList();
      list.push(10);
      list.push(20);
      expect(list.pop()).toBe(20);
      expect(list.pop()).toBe(10);
    });
    it('push/shift', function () {
      var list = new LinkedList();
      list.push(10);
      list.push(20);
      expect(list.shift()).toBe(10);
      expect(list.shift()).toBe(20);
    });
    it('unshift/shift', function () {
      var list = new LinkedList();
      list.unshift(10);
      list.unshift(20);
      expect(list.shift()).toBe(20);
      expect(list.shift()).toBe(10);
    });
    it('unshift/pop', function () {
      var list = new LinkedList();
      list.unshift(10);
      list.unshift(20);
      expect(list.pop()).toBe(10);
      expect(list.pop()).toBe(20);
    });
    it('example', function () {
      var list = new LinkedList();
      list.push(10);
      list.push(20);
      expect(list.pop()).toBe(20);
      list.push(30);
      expect(list.shift()).toBe(10);
      list.unshift(40);
      list.push(50);
      expect(list.shift()).toBe(40);
      expect(list.pop()).toBe(50);
      expect(list.shift()).toBe(30);
    });
    it('can count its elements', function () {
      var list = new LinkedList();
      expect(list.count()).toBe(0);
      list.push(10);
      expect(list.count()).toBe(1);
      list.push(20);
      expect(list.count()).toBe(2);
    });
    it('deletes the last element from the list', function () {
      var list = new LinkedList();
      list.push(10);
      list.push(20);
      list.push(30);
      list.delete(20);
      expect(list.count()).toBe(2);
      expect(list.pop()).toBe(30);
      expect(list.shift()).toBe(10);
    });
    it('deletes the only element', function () {
      var list = new LinkedList();
      list.push(10);
      list.delete(10);
  
      expect(list.count()).toBe(0);
    });
  });
  