README.md

Sample using Docker Compose

Requirements

• Docker Desktop for Mac/Windows/Linux

  Recommended resources:

  • 3 cores
  • 2 GB RAM
  • 512 MB swap
  • 4 GB disk

Pull in the dependencies

$ npm install

Starting the emulators

$ npm run start
...
Firebase Emulators are running. Use 'docker compose down' to run them down.

Unlike with the npm run start in the sample folder, here control returns to the command line. To see the emulators' console output, go to Docker > Dashboard > Containers / Apps > sampledc > sampledc-emul-1:

Warm-up

Since Firebase doesn't automatically warm up the emulators (i.e. the first tests are way slower than subsequent), there's a second container that does this, sampledc-warm-up-1.

This helps us reach a predictable timeout of 2000 ms for all the tests.

Just as in the sample folder, you can now:

$ npm test

$ npm run test:fns:greet
$ npm run test:rules:project

The differences are:

• Firebase emulators run under Docker, not natively on your system (no devDependency on firebase-tools! 🥳 )
• Concurrency is handled with Docker Compose - no need for concurrently.

Using in your own projects

Unfortunately, there's a compromise between maintainability of this repo - and the ease of taking this folder as a template for your own work.

If you look at the internals, there's a lot of details where things (eg. Docker Compose mappings) point to the normal sample folder. The author didn't want to duplicate the test definitions. This makes things look complicated, but they need not be.

If you decide to use Docker Compose for your project's testing, the suggestion is to first uncomplicate this folder, then use it as a sample.

• Remove references to sample by eg. moving folders like test-fns, test-rules here.
• ..so that eventually you'll be able to remove the whole ../sample folder.

At this stage, test that the setup works:

• docker compose down
• npm test

Once the tests passes, you can use the folder as a template for your own work. :)