如何使用用于 JS 开发的 firebase Emulator 设置 firebase firestore 和云功能测试套件

Question

根据 firebase 团队的以下 google I/O (2019) 帖子，新的模拟器允许我们结合 firebase/database 和云功能来完全模拟我们的 firebase 服务器代码。这也应该意味着我们应该能够为它编写测试。

我们正在发布一个全新的 Cloud Functions 模拟器，它还可以 与 Cloud Firestore 模拟器通信。所以如果你想建立 触发 Firestore 文档更新并写入的函数 数据返回数据库，您可以对整个流程进行编码和测试 本地在您的笔记本电脑上（来源：Firebase Blog Entry）

我可以找到多个资源来查看/描述每个单独的模拟，但不能全部放在一起

1. Unit Testing Cloud Function
2. Emulate Database writes
3. Emulate Firestore writes

Answer 1

要为允许您模拟读/写和设置测试数据的云功能设置测试环境，您必须执行以下操作。请记住，这确实模拟/触发了云功能。因此，在写入 firestore 后，您需要稍等片刻，直到云函数完成写入/处理，然后才能读取断言数据。

可以在此处找到包含以下代码的示例 repo：https://github.com/BrandiATMuhkuh/jaipuna-42-firebase-emulator。

前提条件

我假设此时您已经设置了一个 firebase 项目，其中包含一个函数文件夹和 index.js。测试稍后将位于functions/test 文件夹中。如果您没有项目设置，请使用firebase init 设置项目。

安装依赖项

首先将以下依赖项添加/安装：mocha、@firebase/rules-unit-testing、firebase-functions-test、firebase-functions、firebase-admin、firebase-tools 到 functions/package.json 而不是根文件夹。

cd "YOUR-LOCAL-EMULATOR"/functions (for example cd C:\Users\User\Documents\FirebaseLocal\functions)

npm install --save-dev mocha
npm install --save-dev firebase-functions-test
npm install --save-dev @firebase/rules-unit-testing
npm install firebase-admin
npm install firebase-tools

替换所有jaipuna-42-firebase-emulator 名称

使用自己的project-id 非常重要。它必须是您自己项目的project-id，并且必须存在。假身份证是不行的。因此，在下面的代码中搜索所有 jaipuna-42-firebase-emulator 并将其替换为您的 project-id。

index.js 示例云函数

// functions/index.js

const functions = require("firebase-functions");
const admin = require("firebase-admin");

// init the database
admin.initializeApp(functions.config().firebase);
let fsDB = admin.firestore();

const heartOfGoldRef = admin
    .firestore()
    .collection("spaceShip")
    .doc("Heart-of-Gold");

exports.addCrewMemeber = functions.firestore.document("characters/{characterId}").onCreate(async (snap, context) => {
    console.log("characters", snap.id);

    // before doing anything we need to make sure no other cloud function worked on the assignment already
    // don't forget, cloud functions promise an "at least once" approache. So it could be multiple
    // cloud functions work on it. (FYI: this is called "idempotent")

    return fsDB.runTransaction(async t => {
        // Let's load the current character and the ship
        const [characterSnap, shipSnap] = await t.getAll(snap.ref, heartOfGoldRef);

        // Let's get the data
        const character = characterSnap.data();
        const ship = shipSnap.data();

        // set the crew members and count
        ship.crew = [...ship.crew, context.params.characterId];
        ship.crewCount = ship.crewCount + 1;

        // update character space status
        character.inSpace = true;

        // let's save to the DB
        await Promise.all([t.set(snap.ref, character), t.set(heartOfGoldRef, ship)]);
    });
});

mocha 测试文件 index.test.js

// functions/test/index.test.js


// START with: yarn firebase emulators:exec "yarn test --exit"
// important, project ID must be the same as we currently test

// At the top of test/index.test.js
require("firebase-functions-test")();

const assert = require("assert");
const firebase = require("@firebase/testing");

// must be the same as the project ID of the current firebase project.
// I belive this is mostly because the AUTH system still has to connect to firebase (googles servers)
const projectId = "jaipuna-42-firebase-emulator";
const admin = firebase.initializeAdminApp({ projectId });

beforeEach(async function() {
    this.timeout(0);
    await firebase.clearFirestoreData({ projectId });
});

async function snooz(time = 3000) {
    return new Promise(resolve => {
        setTimeout(e => {
            resolve();
        }, time);
    });
}

it("Add Crew Members", async function() {
    this.timeout(0);

    const heartOfGold = admin
        .firestore()
        .collection("spaceShip")
        .doc("Heart-of-Gold");

    const trillianRef = admin
        .firestore()
        .collection("characters")
        .doc("Trillian");

    // init crew members of the Heart of Gold
    await heartOfGold.set({
        crew: [],
        crewCount: 0,
    });

    // save the character Trillian to the DB
    const trillianData = { name: "Trillian", inSpace: false };
    await trillianRef.set(trillianData);

    // wait until the CF is done.
    await snooz();

    // check if the crew size has change
    const heart = await heartOfGold.get();
    const trillian = await trillianRef.get();

    console.log("heart", heart.data());
    console.log("trillian", trillian.data());

    // at this point the Heart of Gold has one crew member and trillian is in space
    assert.deepStrictEqual(heart.data().crewCount, 1, "Crew Members");
    assert.deepStrictEqual(trillian.data().inSpace, true, "In Space");
});

运行测试

要一次性运行测试和模拟器，我们导航到functions 文件夹并写入yarn firebase emulators:exec "yarn test --exit"。此命令也可以在您的 CI 管道中使用。或者你也可以改用npm test。

如果一切正常，您应该会看到以下输出

  √ Add Crew Members (5413ms)

  1 passing (8S)

Answer 2

对于任何在测试 Firestore 触发器方面遇到困难的人，我制作了一个示例存储库，希望能对其他人有所帮助。

https://github.com/benwinding/example-jest-firestore-triggers

它使用 jest 和本地 firebase 模拟器。