如何使用 express 模拟导入的依赖项？

Question

我正在对一个 express 函数进行单元测试。 express 函数使用我想模拟的导入（条带）。如何在使用 express 功能时模拟导入？问题是它是一个全局导入，如果我能以某种方式将它作为 express 函数的参数，我的问题就会得到解决。

表达代码（作为firebase_functions.subscribe导出到测试文件）

const functions = require('firebase-functions');
const stripe = require('stripe')(functions.config().stripe.client_id);

module.exports = async function( request, response ) {
  if( !request.query.id_token ) {
    response.status(400).json({message: 'id_token has not been provided'});
    return;
  }

  await admin.auth()
  .verifyIdToken( request.query.id_token )
  .then( id_token => {
    // pseudo-code: something is done with e.g. 
    const message = await stripe.xxx( id_token ); // returns 'some result I got using the stripe Mock in the process'
    response.status(200).json({message});
    return;
  })
  .catch( error => {
    return response.status(401).json({message: 'You are currently not logged in as an authorised user'});
  })
}

测试代码摘录

describe('subscribe( request, response)', () => {
  it( 'should redirect an user to an url for stripe subscriptions', async() => {
    // arrange
    const response = new ResponseSpy();
    const id_token = await get_id_token();
    const request = { query: { id_token }};
    // act
    await firebase_functions.subscribe( request, response );
    // assert
    assert.deepStrictEqual( result.json, {message: 'some result I got using the stripe Mock in the process'} );
  });
});

Answer 1

由于您使用firebase-functions，您最好使用firebase-functions-test包来测试这些云功能。

为了模拟独立函数stripe，您需要proxyquire 包。如需更多信息，请参阅How to use Link Seams with CommonJS。

我将使用sinon.js 作为存根库。而且，我将使用firebase-functions-test 包中的offline mode 来编写单元测试。

这里是单元测试解决方案：

index.js:

const admin = require('firebase-admin');
const app = admin.initializeApp();
const functions = require('firebase-functions');
const stripe = require('stripe')(functions.config().stripe.client_id);

module.exports = async function (request, response) {
  if (!request.query.id_token) {
    response.status(400).json({ message: 'id_token has not been provided' });
    return;
  }

  await app
    .auth()
    .verifyIdToken(request.query.id_token)
    .then(async (id_token) => {
      const message = await stripe.xxx(id_token);
      response.status(200).json({ message });
      return;
    })
    .catch((error) => {
      return response.status(401).json({ message: 'You are currently not logged in as an authorised user' });
    });
};

index.test.js:

const test = require('firebase-functions-test')();
const admin = require('firebase-admin');
test.mockConfig({ stripe: { client_id: 'client_123' } });
const sinon = require('sinon');
const proxyquire = require('proxyquire');

describe('66157457', () => {
  afterEach(() => {
    sinon.restore();
  });
  it('should send message', async () => {
    const authStub = { auth: sinon.stub().returnsThis(), verifyIdToken: sinon.stub().resolves('token_123') };
    const adminInitStub = sinon.stub(admin, 'initializeApp').returns(authStub);
    const request = { query: { id_token: 'abc' } };
    const response = { status: sinon.stub().returnsThis(), json: sinon.stub() };
    const stripeStub = { xxx: sinon.stub().resolves('fake message') };
    const stripeFactory = sinon.stub().returns(stripeStub);
    const subscribe = proxyquire('./', {
      stripe: stripeFactory,
    });
    await subscribe(request, response);
    sinon.assert.calledOnce(adminInitStub);
    sinon.assert.calledWithExactly(stripeFactory, 'client_123');
    sinon.assert.calledOnce(authStub.auth);
    sinon.assert.calledWithExactly(authStub.verifyIdToken, 'abc');
    sinon.assert.calledWithExactly(stripeStub.xxx, 'token_123');
    sinon.assert.calledWithExactly(response.status, 200);
    sinon.assert.calledWithExactly(response.json, { message: 'fake message' });
    test.cleanup();
  });
});

单元测试结果：

  66157457
    ✓ should send message (145ms)


  1 passing (148ms)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |   76.92 |       50 |   66.67 |   76.92 |                   
 index.js |   76.92 |       50 |   66.67 |   76.92 | 8-9,21            
----------|---------|----------|---------|---------|-------------------