@technobuddha/library/src/priority-queue.test.ts

A large library of useful functions

import { compareNumbers } from './compare-numbers.ts';
import { PriorityQueue } from './priority-queue.ts';

describe('PriorityQueue', () => {
  test('should create a queue', () => {
    const q = new PriorityQueue<number>(compareNumbers);
    q.push(1, 3, 2);
    expect(q.pop()).toBe(1);
    expect(q.pop()).toBe(2);
    expect(q.pop()).toBe(3);
  });

  test('should iterate', () => {
    const q = new PriorityQueue<number>(compareNumbers);
    q.push(1, 3, 2);
    let i = 0;
    for (const pq of q) {
      expect(pq).toBe(++i);
    }
    // iterating should not change contents
    i = 0;
    for (const pq of q) {
      expect(pq).toBe(++i);
    }
  });

  test('should return size', () => {
    const q = new PriorityQueue<number>(compareNumbers);
    q.push(1, 3, 2);
    expect(q.size).toBe(3);
  });

  test('should return map values', () => {
    const q = new PriorityQueue<number>(compareNumbers);
    q.push(1, 3, 2);
    expect(q.map((f) => f * 2)).toEqual([2, 4, 6]);
    // mapping should not change contents
    expect(q.map((f) => f * 2)).toEqual([2, 4, 6]);
  });

  test('should reorder the queue', () => {
    const q = new PriorityQueue<number>(compareNumbers);
    q.push(1, 3, 2);

    q.reorder((a, b) => compareNumbers(b, a));

    expect(q.pop()).toBe(3);
    expect(q.pop()).toBe(2);
    expect(q.pop()).toBe(1);
  });
});