@dxzmpk/js-algorithms-data-structures/src/data-structures/doubly-linked-list/__test__/DoublyLinkedListNode.test.js

Algorithms and data-structures implemented on JavaScript

import DoublyLinkedListNode from '../DoublyLinkedListNode';

describe('DoublyLinkedListNode', () => {
  it('should create list node with value', () => {
    const node = new DoublyLinkedListNode(1);

    expect(node.value).toBe(1);
    expect(node.next).toBeNull();
    expect(node.previous).toBeNull();
  });

  it('should create list node with object as a value', () => {
    const nodeValue = { value: 1, key: 'test' };
    const node = new DoublyLinkedListNode(nodeValue);

    expect(node.value.value).toBe(1);
    expect(node.value.key).toBe('test');
    expect(node.next).toBeNull();
    expect(node.previous).toBeNull();
  });

  it('should link nodes together', () => {
    const node2 = new DoublyLinkedListNode(2);
    const node1 = new DoublyLinkedListNode(1, node2);
    const node3 = new DoublyLinkedListNode(10, node1, node2);

    expect(node1.next).toBeDefined();
    expect(node1.previous).toBeNull();
    expect(node2.next).toBeNull();
    expect(node2.previous).toBeNull();
    expect(node3.next).toBeDefined();
    expect(node3.previous).toBeDefined();
    expect(node1.value).toBe(1);
    expect(node1.next.value).toBe(2);
    expect(node3.next.value).toBe(1);
    expect(node3.previous.value).toBe(2);
  });

  it('should convert node to string', () => {
    const node = new DoublyLinkedListNode(1);

    expect(node.toString()).toBe('1');

    node.value = 'string value';
    expect(node.toString()).toBe('string value');
  });

  it('should convert node to string with custom stringifier', () => {
    const nodeValue = { value: 1, key: 'test' };
    const node = new DoublyLinkedListNode(nodeValue);
    const toStringCallback = (value) => `value: ${value.value}, key: ${value.key}`;

    expect(node.toString(toStringCallback)).toBe('value: 1, key: test');
  });
});