定时器

¥Timers

模拟定时器是软件测试中常用的一种技术，用于模拟和控制定时器（例如 setInterval 和 setTimeout）的行为，而无需实际等待指定的时间间隔。

¥Mocking timers is a technique commonly used in software testing to simulate and control the behavior of timers, such as setInterval and setTimeout, without actually waiting for the specified time intervals.

有关方法和功能的完整列表，请参阅 MockTimers 类。

¥Refer to the MockTimers class for a full list of methods and features.

这使得开发者能够为时间相关的功能编写更可靠和可预测的测试。

¥This allows developers to write more reliable and predictable tests for time-dependent functionality.

下面的示例展示了如何模拟 setTimeout。使用 .enable({ apis: ['setTimeout'] }); 它将模拟 node:timers 和 node:timers/promises 模块以及 Node.js 全局上下文中的 setTimeout 函数。

¥The example below shows how to mock setTimeout. Using .enable({ apis: ['setTimeout'] }); it will mock the setTimeout functions in the node:timers and node:timers/promises modules, as well as from the Node.js global context.

注意：该 API 目前不支持 import { setTimeout } from 'node:timers' 等解构函数。

¥Note: Destructuring functions such as import { setTimeout } from 'node:timers' is currently not supported by this API.

import assert from 'node:assert';
import { mock, test } from 'node:test';

test('mocks setTimeout to be executed synchronously without having to actually wait for it', () => {
  const fn = mock.fn();

  // Optionally choose what to mock
  mock.timers.enable({ apis: ['setTimeout'] });
  setTimeout(fn, 9999);
  assert.strictEqual(fn.mock.callCount(), 0);

  // Advance in time
  mock.timers.tick(9999);
  assert.strictEqual(fn.mock.callCount(), 1);

  // Reset the globally tracked mocks.
  mock.timers.reset();

  // If you call reset mock instance, it will also reset timers instance
  mock.reset();
});const assert = require('node:assert');
const { mock, test } = require('node:test');

test('mocks setTimeout to be executed synchronously without having to actually wait for it', () => {
  const fn = mock.fn();

  // Optionally choose what to mock
  mock.timers.enable({ apis: ['setTimeout'] });
  setTimeout(fn, 9999);
  assert.strictEqual(fn.mock.callCount(), 0);

  // Advance in time
  mock.timers.tick(9999);
  assert.strictEqual(fn.mock.callCount(), 1);

  // Reset the globally tracked mocks.
  mock.timers.reset();

  // If you call reset mock instance, it will also reset timers instance
  mock.reset();
});拷贝

每个测试的 TestContext 对象的模拟属性中也公开了相同的模拟功能。通过测试上下文进行模拟的好处是，一旦测试完成，测试运行器将自动恢复所有模拟的定时器功能。

¥The same mocking functionality is also exposed in the mock property on the TestContext object of each test. The benefit of mocking via the test context is that the test runner will automatically restore all mocked timers functionality once the test finishes.

import assert from 'node:assert';
import { test } from 'node:test';

test('mocks setTimeout to be executed synchronously without having to actually wait for it', (context) => {
  const fn = context.mock.fn();

  // Optionally choose what to mock
  context.mock.timers.enable({ apis: ['setTimeout'] });
  setTimeout(fn, 9999);
  assert.strictEqual(fn.mock.callCount(), 0);

  // Advance in time
  context.mock.timers.tick(9999);
  assert.strictEqual(fn.mock.callCount(), 1);
});const assert = require('node:assert');
const { test } = require('node:test');

test('mocks setTimeout to be executed synchronously without having to actually wait for it', (context) => {
  const fn = context.mock.fn();

  // Optionally choose what to mock
  context.mock.timers.enable({ apis: ['setTimeout'] });
  setTimeout(fn, 9999);
  assert.strictEqual(fn.mock.callCount(), 0);

  // Advance in time
  context.mock.timers.tick(9999);
  assert.strictEqual(fn.mock.callCount(), 1);
});拷贝