Google Translate doesn't get unit tested in CI (Github Actions)

[achimr]

Root cause:
The method to authenticate Github Actions code to Google Cloud is described here (this is code provided by Google). After a checkout of the repository, the authentication methods create temporary JSON files in the repository folders. However, nbdev 2.0 CI code checks out the repository again using the Github actions/checkout@v3 with the default clean=true option, overwriting the Google Cloud JSON authentication files. Subsequent calls to Google Cloud therefore cannot be authenticated anymore.

The proper way to fix this would be:

1. Fork fastai/workflows
2. Add an option clean_repo to fastai/workflows/nbdev-ci/actions.yml to allow setting the clean option for actions/checkout@v3 (default: true)
3. Add the code to add Google Cloud authentication to this repository in .github/workflows/test.yaml with the option clean_repo=false set
4. Test this fix with the forked fastai workflows
5. Submit PR to fastai
6. After PR is accepted change .github/workflows/test.yaml to use fastai/workflows again instead of the fork

[achimr]

The workaround is to run unit tests with nbdev_test on a local Jupyter notebook instance (ideally with GPU support) or on Google Colab (also ideally with GPU runtime)