使用sinon和chai测试异步函数引发异常

Question

我有这个导出的函数：

module.exports.doThing = async (input) => {
  if(input === '') { throw('no input present') }
  // other stuff
  return input
}

以及它的一个测试文件，在这个文件中，我试图测试当输入无效时是否抛出错误。这是我尝试过的：

const testService = require('../services/testService.js')
const chai = require('chai')
const expect = chai.expect
const sinon = require('sinon')
chai.use(require('sinon-chai'))

describe('doThing', () => {
  it('throws an exception if input is not present', async () => {
    expect(testService.doThing('')).to.be.rejected
  })
})

我得到了错误Error: Invalid Chai property: rejected和UnhandledPromiseRejectionWarning

如何修复此测试？

Answer 1

您可以安装插件chai-as-promised。这允许您执行以下操作：

const testService = require('../services/testService.js')
const chai = require('chai')
    .use(require('chai-as-promised'))
const expect = chai.expect;

describe('doThing', () => {
    it('throws an exception if input is not present', async () => {
        await expect(testService.doThing('')).to.be.rejectedWith('no input present');
    });
    it('should not throw ...', async () => {
        await expect(testService.doThing('some input')).to.be.fulfilled;
    });
})