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tools/core/stdlib/src/structs/Deque/index.test.ts

289 lines
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TypeScript

import { describe, it, expect } from 'vitest';
import { Deque } from '.';
describe('deque', () => {
describe('constructor', () => {
it('create an empty deque if no initial values are provided', () => {
const deque = new Deque<number>();
expect(deque.length).toBe(0);
expect(deque.isEmpty).toBe(true);
});
it('create a deque with the provided initial values', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.length).toBe(3);
expect(deque.peekFront()).toBe(1);
expect(deque.peekBack()).toBe(3);
});
it('create a deque with a single initial value', () => {
const deque = new Deque(42);
expect(deque.length).toBe(1);
expect(deque.peekFront()).toBe(42);
});
it('create a deque with the provided options', () => {
const deque = new Deque<number>(undefined, { maxSize: 5 });
expect(deque.length).toBe(0);
expect(deque.isFull).toBe(false);
});
});
describe('pushBack', () => {
it('add an element to the back', () => {
const deque = new Deque<number>();
deque.pushBack(1).pushBack(2);
expect(deque.peekFront()).toBe(1);
expect(deque.peekBack()).toBe(2);
expect(deque.length).toBe(2);
});
it('throw an error if the deque is full', () => {
const deque = new Deque<number>(undefined, { maxSize: 1 });
deque.pushBack(1);
expect(() => deque.pushBack(2)).toThrow(new RangeError('Deque is full'));
});
it('return this for chaining', () => {
const deque = new Deque<number>();
expect(deque.pushBack(1)).toBe(deque);
});
});
describe('pushFront', () => {
it('add an element to the front', () => {
const deque = new Deque<number>();
deque.pushFront(1).pushFront(2);
expect(deque.peekFront()).toBe(2);
expect(deque.peekBack()).toBe(1);
expect(deque.length).toBe(2);
});
it('throw an error if the deque is full', () => {
const deque = new Deque<number>(undefined, { maxSize: 1 });
deque.pushFront(1);
expect(() => deque.pushFront(2)).toThrow(new RangeError('Deque is full'));
});
it('return this for chaining', () => {
const deque = new Deque<number>();
expect(deque.pushFront(1)).toBe(deque);
});
});
describe('popBack', () => {
it('remove and return the back element', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.popBack()).toBe(3);
expect(deque.length).toBe(2);
});
it('return undefined if the deque is empty', () => {
const deque = new Deque<number>();
expect(deque.popBack()).toBeUndefined();
});
});
describe('popFront', () => {
it('remove and return the front element', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.popFront()).toBe(1);
expect(deque.length).toBe(2);
});
it('return undefined if the deque is empty', () => {
const deque = new Deque<number>();
expect(deque.popFront()).toBeUndefined();
});
});
describe('peekBack', () => {
it('return the back element without removing it', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.peekBack()).toBe(3);
expect(deque.length).toBe(3);
});
it('return undefined if the deque is empty', () => {
const deque = new Deque<number>();
expect(deque.peekBack()).toBeUndefined();
});
});
describe('peekFront', () => {
it('return the front element without removing it', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.peekFront()).toBe(1);
expect(deque.length).toBe(3);
});
it('return undefined if the deque is empty', () => {
const deque = new Deque<number>();
expect(deque.peekFront()).toBeUndefined();
});
});
describe('clear', () => {
it('clear the deque', () => {
const deque = new Deque([1, 2, 3]);
deque.clear();
expect(deque.length).toBe(0);
expect(deque.isEmpty).toBe(true);
});
it('return this for chaining', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.clear()).toBe(deque);
});
});
describe('toArray', () => {
it('return elements from front to back', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.toArray()).toEqual([1, 2, 3]);
});
it('return correct order after mixed operations', () => {
const deque = new Deque<number>();
deque.pushBack(2);
deque.pushBack(3);
deque.pushFront(1);
deque.pushFront(0);
expect(deque.toArray()).toEqual([0, 1, 2, 3]);
});
});
describe('toString', () => {
it('return comma-separated string', () => {
const deque = new Deque([1, 2, 3]);
expect(deque.toString()).toBe('1,2,3');
});
});
describe('iteration', () => {
it('iterate in front-to-back order', () => {
const deque = new Deque([1, 2, 3]);
expect([...deque]).toEqual([1, 2, 3]);
});
it('iterate asynchronously', async () => {
const deque = new Deque([1, 2, 3]);
const elements: number[] = [];
for await (const element of deque)
elements.push(element);
expect(elements).toEqual([1, 2, 3]);
});
});
describe('circular buffer behavior', () => {
it('handle wrap-around correctly', () => {
const deque = new Deque<number>();
for (let i = 0; i < 4; i++)
deque.pushBack(i);
deque.popFront();
deque.popFront();
deque.pushBack(4);
deque.pushBack(5);
expect(deque.toArray()).toEqual([2, 3, 4, 5]);
});
it('grow the buffer when needed', () => {
const deque = new Deque<number>();
for (let i = 0; i < 100; i++)
deque.pushBack(i);
expect(deque.length).toBe(100);
expect(deque.peekFront()).toBe(0);
expect(deque.peekBack()).toBe(99);
});
it('handle alternating front/back operations', () => {
const deque = new Deque<number>();
deque.pushFront(3);
deque.pushBack(4);
deque.pushFront(2);
deque.pushBack(5);
deque.pushFront(1);
expect(deque.toArray()).toEqual([1, 2, 3, 4, 5]);
expect(deque.popFront()).toBe(1);
expect(deque.popBack()).toBe(5);
expect(deque.toArray()).toEqual([2, 3, 4]);
});
});
describe('mixed operations', () => {
it('use as a stack (LIFO)', () => {
const deque = new Deque<number>();
deque.pushBack(1).pushBack(2).pushBack(3);
expect(deque.popBack()).toBe(3);
expect(deque.popBack()).toBe(2);
expect(deque.popBack()).toBe(1);
});
it('use as a queue (FIFO)', () => {
const deque = new Deque<number>();
deque.pushBack(1).pushBack(2).pushBack(3);
expect(deque.popFront()).toBe(1);
expect(deque.popFront()).toBe(2);
expect(deque.popFront()).toBe(3);
});
it('reuse deque after clear', () => {
const deque = new Deque([1, 2, 3]);
deque.clear();
deque.pushBack(4);
expect(deque.length).toBe(1);
expect(deque.peekFront()).toBe(4);
});
it('maxSize limits capacity', () => {
const deque = new Deque<number>(undefined, { maxSize: 3 });
deque.pushBack(1).pushBack(2).pushBack(3);
expect(deque.isFull).toBe(true);
expect(() => deque.pushFront(0)).toThrow(new RangeError('Deque is full'));
deque.popFront();
deque.pushFront(0);
expect(deque.toArray()).toEqual([0, 2, 3]);
});
});
});