如何与Jest共享多个套件中的测试用例？

Posted 2021-04-29

我发现在Node.js REST API的多个集成测试中有很多重复的测试案例。因此，例如，我对每个错误都具有相同属性的端点测试无效请求。

import { app } from 'server';
import * as request from 'supertest';

describe('Authentication tests', () => {
    describe('POST /login', () => {
        // other test cases
        // describe('valid request should ...', () => {...})

        describe('invalid requests with missing fields', () => {
            let response = null;

            beforeAll(async () => {
                await request(app)
                    .post('/login')
                    .expect('Content-Type', 'application/json; charset=utf-8')
                    .field('email', '[e-mail]')
                    .then(res => {
                        response = res;
                    });
            });

            it('should return an invalid status code', () => {
                expect(response.status).toBe(400);
            });

            it('should return a valid error schema', () => {
                expect(typeof response.body).toBe('object');
                expect(response.body).toHaveProperty('error');
                expect(response.body.error).toHaveProperty('code');
                expect(response.body.error).toHaveProperty('message');
            });

            it('should return an error with explicit message', () => {
                expect(response.body.error).toHaveProperty('message');
            });
        });
    });
});

Jest是否提供任何方法来创建一些共享测试，以便我可以封装此错误验证并在其他套件情况下进行声明以避免太多重复？

答案

您可以将这些测试封装到一个函数中。 docs说：

测试必须同步定义，Jest才能收集您的测试。

例如：

function createInvalidRequestTests() {
  describe('invalid request', () => {
    let response;
    beforeAll(() => {
      response = { status: 400, body: { error: { code: 1, message: 'network error' } } };
    });

    it('should return an invalid status code', () => {
      expect(response.status).toBe(400);
    });

    it('should return a valid error schema', () => {
      expect(typeof response.body).toBe('object');
      expect(response.body).toHaveProperty('error');
      expect(response.body.error).toHaveProperty('code');
      expect(response.body.error).toHaveProperty('message');
    });

    it('should return an error with explicit message', () => {
      expect(response.body.error).toHaveProperty('message');
    });
  });
}

然后，您可以使用此功能定义测试。开玩笑的测试跑步者将照常收集和运行这些测试

describe('Authentication tests', () => {
  describe('POST /login', () => {
    describe('valid request', () => {
      it('should login correctly', () => {
        expect(1).toBe(1);
      });
    });

    createInvalidRequestTests();
  });

  describe('POST /register', () => {
    describe('valid request', () => {
      it('should register correctly', () => {
        expect(2).toBe(2);
      });
    });

    createInvalidRequestTests();
  });
});

单元测试结果：

 PASS  src/stackoverflow/58081822/index.spec.ts (9.622s)
  Authentication tests
    POST /login
      valid request
        ✓ should login correctly (5ms)
      invalid request
        ✓ should return an invalid status code
        ✓ should return a valid error schema (2ms)
        ✓ should return an error with explicit message
    POST /register
      valid request
        ✓ should register correctly (1ms)
      invalid request
        ✓ should return an invalid status code (1ms)
        ✓ should return a valid error schema (2ms)
        ✓ should return an error with explicit message (1ms)

Test Suites: 1 passed, 1 total
Tests:       8 passed, 8 total
Snapshots:   0 total
Time:        12.053s, estimated 14s