Set up automated testing

[danieliser]

Now that we have PHPUnit set up and some integration tests created, we need these to be automatically run during pull requests, commits, merges, etc...

Merge these into something usable.

• https://deliciousbrains.com/deploying-wordpress-plugins-travis/
• https://github.com/deliciousbrains/wp-plugin-build
• https://github.com/kevindees/travis-ci-wordpress/
• https://medium.com/@nihon_rafy/how-to-mock-static-methods-for-unit-tests-in-php-18b2a11458d0
• https://carlalexander.ca/continuous-integration-wordpress/

[fpcorso]

@danieliser I did some research on this and we can definitely utilize GitHub Actions for this since our tests are rather straightforward. The question is: When should we run the tests? Just pushes on master and on PR's to master? Or, should we do PR's to develop too? Should we run the tests for each push to develop too?

[danieliser]

@fpcorso I think this ideally should occur when a PR is submitted against develop, it prevents us from having to patch things in master. This way all new code must pass before merging.

Probably same for linting and other checks as well.

[fpcorso]

@danieliser I see two problems doing it only for PR's for develop:

1. There are several smaller items that we commit directly to develop. Then, we branch off the release/x branch where we also commit to. So, when that goes to get merged into master it can contain quite a bit of code that wasn't in PR's for develop.
2. What about hotfix/x branches? We branch those off of master and then merge back into master so those wouldn't get tested.

This is why I was thinking we should also do PR's to master as well.

[danieliser]

@fpcorso My only concern with doing it off master might have been misplaced. For some reason I was thinking that would also pick up all the old code that is already malformatted, but it is probably only scanning the lines committed in the merge, otherwise thinking it through the branches merged into develop would also have that old/dirty code.

So I guess all merges into master & develop ?