如何在 Jest afterAll 挂钩中关闭 Express 服务器

Question

我正在尝试使用 Jest 为我的 Express 服务器编写集成测试。由于 Jest 并行运行测试（并且我想避免使用 --runInBand 按顺序运行测试），因此我使用 get-port 库来查找随机可用端口，以便不同的测试套件不会发生端口冲突。

我的测试都运行成功，唯一的问题是服务器未能在afterAll 挂钩内正确关闭。这会导致 Jest 在控制台中打印以下内容...

Jest did not exit one second after the test run has completed.
This usually means that there are asynchronous operations that weren't stopped in your tests.
Consider running Jest with `--detectOpenHandles` to troubleshoot this issue.

当我使用--detectOpenHandles 标志时，Jest 只是在测试完成后挂起。控制台不会打印任何内容。

这是我的测试代码...

let axios = require('axios')
const getPort = require('get-port')
const { app } = require('../../index')
const { Todo } = require('../../models')

// set reference to server to access
// from within afterAll hook
let server

beforeAll(async () => {
  const port = await getPort()
  axios = axios.create({ baseURL: `http://localhost:${port}` })
  server = app.listen(port)
})

afterAll(() => {
  server.close()
})

describe('GET /todos', () => {
  it('returns a list of todos', async () => {
    const { data: todos } = await axios.get('/todos')
    todos.forEach(todo => {
      expect(Todo.validate(todo)).toEqual(true)
    })
  })
})

Answer 1

我在这个问题上的 github 线程上。这正是适合我的配置。在 package.json 中

"test": "jest --no-cache  --detectOpenHandles --runInBand --forceExit",

这是测试文件中的配置

afterEach(async () => {
  await server.close();
});

afterAll(async () => {
  await new Promise(resolve => setTimeout(() => resolve(), 10000)); // avoid jest open handle error
});

beforeEach(() => {
  // eslint-disable-next-line global-require
  server = require('../index');
  jest.setTimeout(30000);
});

或者你只有 afterAll 为测试正文中的每个测试单独设置超时和设置超时。这是下面的示例

afterEach(async () => {
  await server.close();
});

afterAll(async () => {
  await new Promise(resolve => setTimeout(() => resolve(), 10000)); // avoid jest open handle error
});

beforeEach(() => {
  // eslint-disable-next-line global-require
  server = require('../index');
});


describe('POST /customers', () => {
  jest.setTimeout(30000);
  test('It creates a customer', async () => {
    const r = Math.random()
      .toString(36)
      .substring(7);
    const response = await request(server)
      .post('/customers')
      .query({
        name: r,
        email: `${r}@${r}.com`,
        password: 'beautiful',
      });
    // console.log(response.body);
    expect(response.body).toHaveProperty('customer');
    expect(response.body).toHaveProperty('accessToken');
    expect(response.statusCode).toBe(200);
  });
});