使用 Jasmine 和 Typescript 测试 Firebase 的云功能

Question

我目前正在研究 Google Cloud Functions 并且有一些用 typescript 编写的基本测试函数。

函数按预期工作，我现在正尝试使用 Jasmine 创建单元测试。（我没有按照文档使用 Chai/sinon，因为我项目的其余部分使用 jasmine）。

我有两个问题 1) 由于这个错误

，测试没有运行

throw new Error('Firebase config variables are not available. ' + ^ Error: Firebase config variables are not available. Please use the latest version of the Firebase CLI to deploy this function

2) 鉴于测试确实运行，我不确定如何测试响应是否符合预期。

索引文件

import * as functions from 'firebase-functions'

import { helloWorldHandler } from  './functions/hello-world';

export let helloWorld = functions.https.onRequest((req, res) => {
    helloWorldHandler(req, res);
});

正在测试的文件

export let helloWorldHandler = (request, response) => {
    response.send("Hello from Firebase Cloud!");
}

规格

import {} from 'jasmine';
import * as functions from 'firebase-functions'
import { helloWorldHandler } from './hello-world';
import * as endpoints from '../index';

describe('Cloud Functions : Hello World', () => {

    let configStub = {
        firebase: {
            databaseURL: "https://myProject.firebaseio.com",
            storageBucket: "myProject.appspot.com",
        }
    };

    it('should return correct message', () => {

        let spy = spyOn(functions, 'config').and.returnValue(configStub);

        const expected = 'Hello from Firebase Cloud!';
        // A fake request and response objects
        const req : any = {};
        const res : any = { };

        endpoints.helloWorld(req, res);

         //here test response from helloWorld is as expected

      });


});

Answer 1

如果您正在编写单元测试，那么您不想测试第三方 API。因此，目标应该是隔离您的代码逻辑并对其进行测试。端到端测试最适合对集成进行回归测试。

所以这里的第一步是从图片中删除 firebase-functions 和数据库 SDK 等工具（尽可能合理）。我通过将我的库与函数逻辑分开来实现这一点，如下所示：

// functions/lib/http.js
exports.httpFunction = (req, res) => {
   res.send(`Hello ${req.data.foo}`);
};

// functions/index.js
const http = require('lib/http');
const functions = require('firebase-functions');

// we have decoupled the Functions invocation from the method
// so the method can be tested without including the functions lib!
functions.https.onRequest(http.httpFunction);

现在我有了可以通过单元测试测试的很好的隔离逻辑。我模拟了将传递到我的方法中的任何参数，从图片中删除了第三方 API。

所以这是我在 Jasmine 中的单元测试的样子：

// spec/lib/http.spec.js
const http = require('../functions/lib/http');

describe('functions/lib/http', () => {
   expect('send to be called with "hello world"', () => {
      // first thing to do is mock req and res objects
      const req = {data: {foo: 'world'}};
      const res = {send: (s) => {});

      // now let's monitor res.send to make sure it gets called
      spyOn(res, 'send').and.callThrough();

      // now run it
      http.httpFunction(req, res);

      // new test it
      expect(res.send).toHaveBeenCalledWith("Hello world");
   });
});

测试第三方库有很多复杂性。此处的最佳答案是尽早应用 TDD/BDD 原则并将第三方库抽象为可以轻松模拟的服务。

例如，如果我在我的函数中与 Firebase Admin 进行交互，我很容易最终得到一个有很多第三方依赖项需要应对的方法：

// functions/lib/http.js
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const env = require('./env');
const serviceAccount = require(env.serviceAccountPath);

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: `https://${env.dbUrl}.firebaseio.com`
});

exports.httpFunction = (req, res) => {
   let path = null;
   let data = null;

   // this is what I really want to test--my logic!
   if( req.query.foo ) {
      path = 'foo';
      data = 1;
   }

   // but there's this third library party coupling :(
   if( path !== null ) {
     let ref = admin.database.ref().child(path);
     return ref.set(data)
        .then(() => res.send('done'))
        .catch(e => res.status(500).send(e));
   }
   else {
      res.status(500).send('invalid query');
   }
};

要测试此示例，我必须包含并初始化 Functions 以及 Firebase Admin SDK，否则我必须找到一种方法来模拟这些服务。所有这些看起来都是一项相当大的工作。相反，我可以有一个 DataStore 抽象并利用它：

// An interface for the DataStore abstraction
// This is where my Firebase logic would go, neatly packaged
// and decoupled
class DataStore {
   set: (path, data) => {
      // This is the home for admin.database.ref(path).set(data);
   }
}

// An interface for the HTTPS abstraction
class ResponseHandler {
   success: (message) => { /* res.send(message); */ }
   fail: (error) => { /* res.status(500).send(error); */ } 
}

如果我现在添加从 Functions 过程中抽象出我的逻辑的第一个原则，那么我的布局如下所示：

// functions/lib/http.js
exports.httpFunction = (query, responseHandler, dataStore) => {
   if( query.foo ) {
      return dataStore.set('foo', 1)
        .then(() => responseHandler.success())
        .catch(e => responseHandler.fail(e));
   }
   else {
      responseHandler.fail('invalid query');
   }
};

允许我编写一个更优雅的单元测试：

// spec/lib/http
describe('functions/lib/http', () => {
   expect('is successful if "foo" parameter is passed', () => {
      // first thing to do is mock req and res objects
      const query = {foo: 'bar'};
      const responseHandler = {success: () => {}, fail: () => {});
      const dataStore = {set: () => {return Promise.resolve()}};

      // now let's monitor the results
      spyOn(responseHandler, 'success');

      // now run it
      http.httpFunction(query, responseHandler, dataStore);

      // new test it
      expect(res.success).toHaveBeenCalled();
   });
});

我的代码的其余部分也不错：

// functions/lib/firebase.datastore.js
// A centralized place for our third party lib!
// Less mocking and e2e testing!
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const serviceAccount = require(env.serviceAccountPath);

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: `https://${env.dbUrl}.firebaseio.com`
});

exports.set = (path, data) => {
  return admin.database.ref(path).set(data);
};

// functions/index.js
const functions = require('firebase-functions');
const dataStore = require('./lib/firebase.datastore');
const ResponseHandler = require('./lib/express.responseHandler');
const env = require('./env');
const http = require('./lib/http');

dataStore.initialize(env);

exports.httpFunction = (req, res) => {
   const handler = new ResponseHandler(res);
   return http.httpFunction(req.query, handler, dataStore);
};

更不用说从良好的 BDD 心态开始，我还以模块化的方式很好地隔离了我的项目的组件，当我们在第 2 阶段发现所有范围蔓延时，这会很好。: )

使用 Jasmine 和 Typescript 测试 Firebase 的云功能

Testing Cloud Functions for Firebase with Jasmine and Typescript

jasmine

firebase

typescript

google-cloud-functions