Sinon 存根作为 node express 中间件被跳过

Question

我正在尝试测试特定路线的行为。即使我创建了一个存根，它也会继续运行中间件。我希望事件身份验证暂时通过。我知道此时它并不是真正的“单元”测试。我快到那里了。我还稍微简化了代码。这是要测试的代码：

const { rejectUnauthenticated } = require('../modules/event-authentication.middleware');

router.get('/event', rejectUnauthenticated, (req, res) => {
  res.sendStatus(200);
});

这是我要跳过的中间件：

const rejectUnauthenticated = async (req, res, next) => {
  const { secretKey } = req.query;
  if (secretKey) {
    next();
  } else {
    res.status(403).send('Forbidden. Must include Secret Key for Event.');
  }
};

module.exports = {
  rejectUnauthenticated,
};

测试文件：

const chai = require('chai');
const chaiHttp = require('chai-http');
const sinon = require('sinon');
let app;
const authenticationMiddleware = require('../server/modules/event-authentication.middleware');

const { expect } = chai;
chai.use(chaiHttp);

describe('with correct secret key', () => {
  it('should return bracket', (done) => {
    sinon.stub(authenticationMiddleware, 'rejectUnauthenticated')
      .callsFake(async (req, res, next) => next());

    app = require('../server/server.js');

    chai.request(app)
      .get('/code-championship/registrant/event')
      .end((err, response) => {
        expect(response).to.have.status(200);
        authenticationMiddleware.rejectUnauthenticated.restore();
        done();
      });
  });
});

我尝试过其他类似的问题，例如：How to mock middleware in Express to skip authentication for unit test? 和这个：node express es6 sinon stubbing middleware not working 但我仍然从应该跳过的中间件中获得 403。我还在调试模式下运行了测试，所以我知道应该存根的中间件函数仍在运行。

这是我的代码存根的问题吗？这是 ES6 的问题吗？

我可以重组我的代码或测试以使其工作吗？

Answer 1

存根代码确实存在问题。

当您需要服务器文件时

const app = require('../server/server.js');

您的应用是使用整套中间件创建的，包括rejectUnauthenticated，对后者的引用存储在app 中。

当你这样做时

sinon.stub(authenticationMiddleware, 'rejectUnauthenticated')
  .callsFake(async (req, res, next) => next());

您替换了authenticationMiddleware 模块的rejectUnauthenticated 导出方法，而不是对已存储的原始rejectUnauthenticated 的引用。

解决方案是创建应用程序（即require('../server/server.js');）在您模拟导出的中间件方法后：

const chai = require('chai');
const chaiHttp = require('chai-http');
const sinon = require('sinon');

// don't create app right away
let app;
const authenticationMiddleware = require('../server/modules/event-authentication.middleware');

const { expect } = chai;
chai.use(chaiHttp);

describe('with correct secret key', () => {
  it('should return bracket', (done) => {
    sinon.stub(authenticationMiddleware, 'rejectUnauthenticated')
      .callsFake(async (req, res, next) => next());

    // method is stubbed, you can create app now
    app = require('../server/server.js');

    chai.request(app)
      .get('/code-championship/registrant/event')
      .end((err, response) => {
        expect(response).to.have.status(200);
        authenticationMiddleware.rejectUnauthenticated.restore();
        done();
      });
  });
});

Answer 2

根据@Sergey 的建议，我确实改用了 Jest。至少对于这种特定情况，它大大简化了实现。对于那些感兴趣的人，这是最终结果：

const express = require('express');
const request = require('supertest');
const registrantRouter = require('../server/routers/registrant.router');

jest.mock('../server/modules/event-authentication.middleware');
const { rejectUnauthenticated } = require('../server/modules/event-authentication.middleware');

const initRegistrantRouter = () => {
  const app = express();
  app.use(registrantRouter);
  return app;
};

describe('GET /registrant', () => {
  test('It should 200 if event authentication passes', async (done) => {
    const app = initRegistrantRouter();
    rejectUnauthenticated.mockImplementation((req, res, next) => next());
    const res = await request(app).get('/event');
    expect(res).toHaveProperty('status', 200);
    done();
  });
  test('It should 403 if event authentication fails', async (done) => {
    const app = initRegistrantRouter();
    rejectUnauthenticated.mockImplementation((req, res) => res.sendStatus(403));
    const res = await request(app).get('/event');
    expect(res).toHaveProperty('status', 403);
    done();
  });
});

还要感谢这篇关于使用 Jest 测试快速应用的有用博文：https://codewithhugo.com/testing-an-express-app-with-supertest-moxios-and-jest/