example-jest-firestore-triggers

This is an example of using Jest with the Firestore emulator. It does:

• Example firestore trigger
• Example test of firestore trigger
• Debug tests in VSCode
• Debug firestore triggers in VSCode

Get Started

Please note:

• To test this repository, you need to connect it to a real firebase project (although when running the firebase emulator, none of database will be changed).
• These scripts depend on yarn (install yarn here), if you want to use npm or you will need to modify the pacakge.json scripts.
• I was unable to get triggers working with @firebase/testing (hopefully this will change), so although firestore is running in the emulator, it's does require a real firebase project.

Initialize Project

1. clone this repo
2. yarn (to install dependencies)
3. add a serviceAccountKey.json to this folder (from your firebase project)
4. change firebase.rc to use the same projectid as the serviceAccountKey.json

Commands

• yarn test
  • This should start the emulator and execute the jest script, then terminate. Good for a CI pipeline.
• yarn test-watch
  • This should start the emulator and execute the jest script in watch-mode. Good for developing.
• yarn start-emulator
  • *This should start the emulator. Good for debugging tests.
  • Debug .spec.js files
    • When it has started, go to VSCode and click debug "Jest Current File" (while in a .spec.js file). You can now step through the jest file.
  • Debug firestore triggers
    • When it has started, go to VSCode and click debug "Attach (to start-emulator)". This connects the debugger to the emulator and you can set breakpoints in the firestore triggers.

Why?

For me it was extremely confusing to setup testing for firebase functions and triggers, this project helped me understand what was going on.