Cloud Native Development with Tailwind, Google Cloud and Firebase/

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Write Tests for the Service

Write Tests for the Service

Follow best practices and write tests for the new "cross-post-to-devto" service you created in the previous lessons.

We'll cover the following...

In this lesson, following best practices, we are going to write a test for the new cross-post-to-devto service. Some people prefer a separate test directory, while others like their test files located next to the production code itself. We will take a “keep-my-tests-close-to-the-code” approach in this course. The concepts you will learn apply regardless of where the tests are located, and you can follow your own preference.

Writing test

All paths and commands below are relative to services/web/firebase/functions.

Start by installing three necessary NPM packages:

npm i -D mocha chai sinon

Each of these dependencies can easily be covered in three separate courses. Please visit their websites for more details, or feel free to use your own testing libraries of choice.

Update the ./package.json to add the following test and pretest scripts:

"scripts": {
  "pretest": "npm run build",
  "test": "mocha './src/**/*.test.js' --reporter spec"
}

{
  "name": "functions",
  "scripts": {
    "lint": "eslint --ext .js,.ts .",
    "build": "tsc",
    "serve": "npm run build && firebase emulators:start --only functions",
    "shell": "npm run build && firebase functions:shell",
    "start": "npm run shell",
    "deploy": "firebase deploy --only functions",
    "logs": "firebase functions:log"
  },
  "engines": {
    "node": "10"
  },
  "main": "lib/index.js",
  "dependencies": {
    "firebase-admin": "^9.2.0",
    "firebase-functions": "^3.11.0",
    "got": "^11.8.2"
  },
  "devDependencies": {
    "@types/node": "^10.17.56",
    "@typescript-eslint/eslint-plugin": "^3.9.1",
    "@typescript-eslint/parser": "^3.8.0",
    "chai": "^4.3.4",
    "eslint": "^7.6.0",
    "eslint-config-google": "^0.14.0",
    "eslint-plugin-import": "^2.22.0",
    "firebase-functions-test": "^0.2.0",
    "mocha": "^8.3.2",
    "sinon": "^10.0.0",
    "typescript": "^3.8.0"
  },
  "private": true
}

This ensures all services are compiled to JavaScript before the test suites run. If you decided earlier to use JavaScript to develop the Firebase Cloud Function services, you do not need the pretest script.

Next, create the test file at ./src/firestore/posts/on-create/cross-post-to-devto/index.test.js ...