Feature/updated autoloading

[darylldoyle]

Description of the Change

This PR updates the class autoloader from using https://gitlab.com/hpierce1102/ClassFinder/ to using https://github.com/spatie/php-structure-discoverer and adds unit tests to ensure it's working as expected.

Spatie are a well known company, who specialise in Open Source packages. This means the package is updated more often and bugs will be fixed more quickly. For example, the last commit in hpierce1102/classfinder was June 18, 2023, whereas the last commit in spatie/php-structure-discoverer was today.

There are a few other benefits of the Spatie package:

• It doesn't rely on the composer.json to load files, meaning we no longer have to deploy that.
• There's no hidden logic; we can see exactly how the classes are being loaded now and what constraints are being put on them.
• We can conditionally cache the class loader, giving it a considerable performance boost on production/staging.

Old Class Loader

New Class Loader

Additionally, during the refactor, I eliminated all the hardcoded strings and awkward configurations needed to get the classloader working. It should now be plug-and-play.

One downside of this change is that it only supports PHP 8.1 upwards, though since every version pre-8.1 is End of Life, I think that's a fair tradeoff, https://www.php.net/supported-versions.php.

How to test the Change

Ensure all classes are still loading and test suite is passing.

Changelog Entry

• Changed - Class loading swapped out for a newer, more performant library.

Credits

Props @darylldoyle

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[darylldoyle]

This is an updated version of the default install-wp-tests.sh, it has a few benefits:

• It has a help command, which ensures engineers that are new to PHPUnit have a way to understand the params of the script
• When run from a Local WP shell, it automatically picks up and uses the MySQL socket.
  It has a sensible set of defaults that will work for 99% of 10up builds, meaning you can run the script without passing any parameters.
• It resolves an issue where the install script thinks it's already installed (because the /tmp directory exists, but the DB isn't installed.