By using Firebase emulators you no longer have to create a second dev firebase project to avoid using production data. You also don't run the risk of having a cloud function crash and run up a huge bill.
In this course, you'll learn how to set up and use Firebase's authentication, function, and Firestore emulators. You will also learn how to safely set up Cloud Function emulation, import seed data into your emulators, and disable the emulators in production.
By the end of this course, you'll be able to confidently set up a safe environment for testing in your own applications!
What you'll learn
Initialize Firebase emulators in your Angular app
Set up and use the authentication, function, and Firestore emulators
Emulate HTTP, callable, and listener cloud functions
Seed your emulators with data
Disable the emulators when in production
Homepage

https://egghead.io/courses/local-app-development-with-the-firebase-emulator-suite-ebd4a2a8