Migrate gem tests from Travis CI to Github Actions with gemika

We currently test most of our gems on Travis CI, but want to migrate those tests to Github Actions. This is a step-by-step guide on how to do this.

Note that this guide requires the gem to use gemika Show archive.org snapshot .

1. Go to a new "ci" branch:

   Copygit checkout -b ci
   

2. Update gemika to version >= 0.5.0 in all your Gemfiles.

3. Have gemika generate a Github Actions workflow definition by running

   Copymkdir -p .github/workflows; bundle exec rake gemika:generate_github_actions_workflow > .github/workflows/test.yml
   

4. Gemika tried to detect which of your Gemfiles needed which database, but is not currently very smart about it. If your test.yml does not set up the database correctly, please adjust it by comparing it with https://github.com/makandra/active_type/blob/master/.github/workflows/test.yml Show archive.org snapshot .

5. If necessary (i.e. the tests use databases), add a spec/support/database.github.yml file with this content:

   Copymysql:
     database: test
     username: root
     password: password
     host: 127.0.0.1
     port: 3306
   
   postgresql:
     database: test
     host: localhost
     username: postgres
     password: postgres
     port: 5432
   

6. Remove the .travis.yml file, and the spec/support/database.travis.yml.

7. Push the branch, and make a PR against master. In the PR you can now see the CI run. Check if it passes.

8. Most likely it will not. Fix the issues. Common issues are

   • You're using Ruby versions that are not supported on Github Actions.
     • The error messages will show you which versions are supported.
     • There is no support for any Ruby version < 2.2. Just drop those, we do not have to support them any longer.
     • Remember to remove unused Gemfiles.
     • Remember to update the .ruby-version file to a version that is actually in the matrix.
   • You might run into issues with the mysql2 gem, including issues bundling, and even segfaults.
     • Use this card to fix these issues.

9. When tests pass, merge to master and delete the CI branch.

10. Replace the Travis CI badge in the README with one like this:

    Copy# MyGem  [![Tests](https://github.com/makandra/my-gem/workflows/Tests/badge.svg)](https://github.com/makandra/my-gem/actions)
    

11. Uninstall the Travis webhook in the Github repo (go to Settings => Webhooks)