[supply][action] add download_apk_from_google_play action (and corresponding supply methods)

[AliSoftware]

Checklist

• I've run bundle exec rspec from the root directory to see all new and existing tests pass
• I've followed the fastlane code style and run bundle exec rubocop -a to ensure the code style is valid
• I see several green ci/circleci builds in the "All checks have passed" section of my PR (connect CircleCI to GitHub if not)
• I've read the Contribution Guidelines
• I've updated the documentation if necessary. N/A; actions documentation are auto-generated anyway

Motivation and Context

This adds a new download_apk_from_google_play action to download the Universal Code-Signed APK generated by Google after you uploaded the AAB.

This is especially useful when you use Play App Signing to sign your app, because in those cases you'll typically use the upload_to_google_play action to upload a .aab to Google Play Console (GPC), and let Google generate and code-sign the .apk files for that .aab (including split APKs for various architectures, but more importantly the Universal one compatible with all devices)

In those situations of using "Play App Signing", you can't use bundletool to generate the signed .apk from the .aab yourself because you don't have the code signing key (only Google has it), so the only option is to download the .apk from GPC.
And it's useful to get the universal, codesigned APK back because we can use it for running UI tests on it, making sure we run those on the exact APK that will be ultimately shipped to end users (including testing things that rely on code-signing signature checks for security and integrity validation).

Description

• Supply::Client
  • Added the list_generated_universal_apks(package_name:, version_code:) method on Supply::Client to be able to call the generatedapks.list API endpoint
  • Added the download_generated_universal_apk(generated_universal_apk:, destination:) method on Supply::Client to be able to call the generatedapks.download API endpoint
  • Added those entry points to the spec/client_spec.rb tests
  • Added a GeneratedUniversalApk model to allow manipulating the result of those methods more easily
• New Action
  • Added the download_universal_apk_from_google_play action as well as its unit tests (spec)

Testing Steps

Run the new Unit Tests:

bundle exec rspec fastlane/spec/actions_specs/download_universal_apk_from_google_play_spec.rb supply/spec/client_spec.rb

[AliSoftware]

@joshdholtz Now that you're back from your vacation 😃 May I kindly ask a review of this one? I'd love to be able to finally use it in our automation soon 🙂

[getaaron]

Are these correct?

[AliSoftware]

Yes. That spec tests methods we expect to be defined on the AndroidPublisher::AndroidPublisherService internal client (not to be confused with the Supply::Client).

Those two particular ones that I added there are documented here in the AndroidPublisherService ruby doc:

• AndroidPublisher::AndroidPublisherService#list_generatedapks
• AndroidPublisher::AndroidPublisherService#download_generatedapk

And those are the ones that I call in the Supply::Client corresponding wrapper methods here and here, respectively.

So all that is correct, and consistent with how the rest of the spec and that file is written 🙂
(Plus, that spec/test passes on CI, while it would be red if those were not correct)

[getaaron]

Ah I see. Thanks! I'm much less familiar with the Android code.

[AliSoftware]

No worries! Took me some time to familiarize myself with the AndroidPublisher API and Supply code and specs as well when I wrote that PR 😅 🙂