firebase-functions-test

What is firebase-functions-test?

The firebase-functions-test npm package is a testing utility for Firebase Cloud Functions. It allows developers to write unit tests for their Firebase functions, simulate function triggers, and mock Firebase services.

What are firebase-functions-test's main functionalities?

Unit Testing

This feature allows you to write unit tests for your Firebase functions. The code sample demonstrates how to mock Firestore and test a function using the firebase-functions-test package.

const firebaseFunctionsTest = require('firebase-functions-test')();
const myFunctions = require('../index');

// Mocking Firestore
const admin = require('firebase-admin');
const sinon = require('sinon');
sinon.stub(admin, 'firestore').get(() => {
  return {
    collection: () => {
      return {
        doc: () => {
          return {
            get: () => Promise.resolve({ data: () => ({ field: 'value' }) })
          };
        }
      };
    }
  };
});

// Testing a function
const wrapped = firebaseFunctionsTest.wrap(myFunctions.myFunction);
wrapped({ data: 'test' }).then((result) => {
  console.log(result);
});

Simulating Function Triggers

This feature allows you to simulate different types of function triggers, such as HTTP requests. The code sample shows how to simulate an HTTP request to test an HTTP-triggered function.

const firebaseFunctionsTest = require('firebase-functions-test')();
const myFunctions = require('../index');

// Simulating an HTTP request
const wrapped = firebaseFunctionsTest.wrap(myFunctions.myHttpFunction);
const req = { query: { text: 'input' } };
const res = { send: (message) => console.log(message) };
wrapped(req, res);

Mocking Firebase Services

This feature allows you to mock Firebase services like Firestore, Realtime Database, etc. The code sample demonstrates how to mock Firestore and test a Firestore-triggered function.

const firebaseFunctionsTest = require('firebase-functions-test')();
const myFunctions = require('../index');

// Mocking Firestore
const admin = require('firebase-admin');
const sinon = require('sinon');
sinon.stub(admin, 'firestore').get(() => {
  return {
    collection: () => {
      return {
        doc: () => {
          return {
            get: () => Promise.resolve({ data: () => ({ field: 'value' }) })
          };
        }
      };
    }
  };
});

// Testing a Firestore-triggered function
const wrapped = firebaseFunctionsTest.wrap(myFunctions.firestoreTrigger);
wrapped({
  before: { data: () => ({ field: 'oldValue' }) },
  after: { data: () => ({ field: 'newValue' }) }
}).then((result) => {
  console.log(result);
});

Other packages similar to firebase-functions-test

mocha

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. While it is not specific to Firebase, it can be used in conjunction with other libraries to test Firebase functions.

jest

Jest is a delightful JavaScript Testing Framework with a focus on simplicity. It works with projects using Babel, TypeScript, Node.js, React, Angular, Vue.js, and Svelte. Jest can be used to test Firebase functions but requires additional setup for mocking Firebase services.

sinon

Sinon is a standalone test spies, stubs, and mocks for JavaScript. It works with any unit testing framework. While Sinon is not specific to Firebase, it is often used to mock Firebase services in tests.

README

Firebase Test SDK for Cloud Functions

The firebase-functions-test is unit testing library for Cloud Functions for Firebase. It is a companion to firebase-functions.

NOTE: This library can only be used with firebase-functions v3.20.1 or above.

Usage

1. Write some Firebase Functions
2. With your testing framework of choice, write a unit-test that imports your Firebase Functions.
3. wrap your Firebase Functions. You can invoke the Firebase Function's handler by invoking the wrap call.

Eg.

import {myFirebaseFunction} from "../index"; // Your Firebase Functions
import firebaseFunctionsTest from "firebase-functions-test";

// Extracting `wrap` out of the lazy-loaded features
const {wrap} = firebaseFunctionsTest();

// `jest-ts` example
test('my unit test', () => {
  const wrappedFirebaseFunction = wrap(myFirebaseFunction);

  // Invoke the firebase function
  wrappedFirebaseFunction();

  // Invoke the firebase function with CloudEvent overrides
  wrappedFirebaseFunction({data: {arbitrary: 'values'}});
});

Examples

• Unit Testing Gen-1 Cloud Functions using Mocha
• Unit Testing Gen-2 Cloud Functions using Mocha
• Unit Testing Gen-2 Cloud Functions using Jest
• Unit Testing Gen-2 Cloud Functions using Jest-Ts

Learn more

Learn more about unit testing Cloud Functions here.

Contributing

To contribute a change, check out the contributing guide.

License

© Google, 2018. Licensed under The MIT License.