如何为节点控制器编写 Jest 单元测试

Question

我是单元测试新手，并尝试为我的控制器 (ProgramsController) 编写测试。据我了解，我想模拟我的 programService 并返回值。 我真的很感激有人可以解决这个问题。然后我可以得到想法并为其他服务编写笑话测试。

我尝试如下并得到错误

ProgramsController.js

class ProgramsController {
    constructor() {
        this.programService = new ProgramService();
    }
    async subscribe(req, res) {
        const { userId, uuid, msisdn, body: { programId } } = req;
        const data = { userId, programId, msisdn, uuid }

        const subscribe = await this.programService.subscribeUser(data);
        res.send({
            status: true,
            message: constant.MSG.SUCCESS,
            friendly_message: constant.MSG.SUCCESS,
            data: subscribe
        }
    }
}
module.exports = ProgramsController;

ProgramService.js

class ProgramService {

    constructor() {
        this.subscriber = new Subscriber();
        this.subsciberProgram = new SubsciberProgram()
    }

    async subscribeUser(data) {
        try {
            const { msisdn, userId, programId, uuid } = data;
                ...

            return subscribedData;

        } catch (error) {
            throw error;
        }
    }
}
module.exports = ProgramService;

test.spec.js

const ProgramsService = require('../src/services/program/programService')
const ProgramsController = require('../src/controllers/programs/programsController')
const programController = new ProgramsController()
const programsService = new ProgramsService()


describe("Check method \'subscribe\' ", () => {
    it('should retrieve success', async () => {

        const serviceRecord = { userId: 1, programId: 1, msisdn: '56768382967', uuid: '46651a19-3ef1-4149-818e-9bd8a5f359ef' };

        jest.spyOn(programsService, 'subscribeUser').mockResolvedValueOnce(serviceRecord);

        const mReq = { body: { programId: 1 }, userId: 1, msisdn: '56768382967', uuid: '46651a19-3ef1-4149-818e-9bd8a5f359ef' };
        const mRes = { status: jest.fn().mockReturnThis(), send: jest.fn() };


        await programController.subscribe(mReq, mRes);

        expect(programsService.subscribeUser).toBeCalledWith(serviceRecord);
        expect(mRes.status).toBeCalledWith(200);

        expect(mRes.send).toBeCalledWith({ program_id: 1, amount: 5, no_of_questions: 10 });
    });
});

------- *** 更新（针对@tmhao2005）*** ---------

test.spec.js

const ProgramsController = require('../src/controllers/programs/programsController')

const serviceRecord = { userId: 1, programId: 1, msisdn: '56768382967', uuid: '46651a19-3ef1-4149-818e-9bd8a5f359ef' };

// Mock subscribe user fn
const mockSubscribeUser = jest.fn().mockResolvedValue(serviceRecord);

// Mock the service
class MockService {
  subscribeUser = mockSubscribeUser;
}

// Apply the mock before the test run
jest.mock('../src/services/program/programService', () => MockService)

describe("Check method \'subscribe\' ", () => {
  it('should retrieve success', async () => {
    const mReq = { body: { programId: 1 }, userId: 1, msisdn: '56768382967', uuid: '46651a19-3ef1-4149-818e-9bd8a5f359ef' };
    const mRes = { status: jest.fn().mockReturnThis(), send: jest.fn() };

    const programController = new ProgramsController()
    await programController.subscribe(mReq, mRes);

    expect(mockSubscribeUser).toBeCalledWith(serviceRecord);
    expect(mRes.status).toBeaCalledWith(200);

    expect(mRes.send).toBeCalledWith({ program_id: 1, amount: 5, no_of_questions: 10 });
  });
});

Answer 1

这里的问题是您的测试中的ProgramsService 实例与您的实际代码不同。在这种情况下，您只需使用 jest.mock 方法简单地模拟整个模块 ProgramsService。这是这个想法的sn-p：

const ProgramsController = require('../src/controllers/programs/programsController')
const serviceRecord = { userId: 1, programId: 1, msisdn: '56768382967', uuid: '46651a19-3ef1-4149-818e-9bd8a5f359ef' };

// Mock subscribe user fn
const mockSubscribeUser = jest.fn().mockResolvedValue(serviceRecord);

// Apply the mock before the test run
jest.mock('../src/services/program/programService', () => class MockService {
  subscribeUser = mockSubscribeUser;
})

describe("Check method \'subscribe\' ", () => {
  it('should retrieve success', async () => {
    const mReq = { body: { programId: 1 }, userId: 1, msisdn: '56768382967', uuid: '46651a19-3ef1-4149-818e-9bd8a5f359ef' };
    const mRes = { status: jest.fn().mockReturnThis(), send: jest.fn() };

    const programController = new ProgramsController()
    await programController.subscribe(mReq, mRes);

    expect(mockSubscribeUser).toBeCalledWith(serviceRecord);
    expect(mRes.status).toBeaCalledWith(200);

    expect(mRes.send).toBeCalledWith({ program_id: 1, amount: 5, no_of_questions: 10 });
  });
});