Add PHPUnit test workflow for multisite

[johnwatkins0]

Feature description

Some relatively recent additions to the plugin have involved small customizations related to multisite environments (example). Currently we only run PHPUnit tests in single-site environments, so there's no easy way to write tests for these features.

Potentially useful for reference:

https://github.com/WordPress/wordpress-develop/blob/master/tests/phpunit/multisite.xml
https://github.com/WordPress/wordpress-develop/blob/master/.github/workflows/phpunit-tests.yml#L257

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Acceptance criteria

Implementation brief

QA testing instructions

Demo

Changelog entry

[thelovekesh]

@westonruter I am planning to add multisite tests workflow using wp-env. Which WP and PHP versions it should cover? or it should be the same as current test workflows. In this case, we will be having 2x test workflows.

[westonruter]

Just adding one additional test with the latest WP version and PHP 7.4 should be good, as that corresponds to the majority of installs.

[westonruter]

As part of this, could you also add a local development command using the Docker environment to test multisite? Maybe you're planning to do that anyway for debugging the current failures anyway.

[thelovekesh]

I have added it as a command and it uses the wp-env.

amp-wp/package.json

Line 146 in ac70da5

"test:php:multisite": "wp-env run phpunit 'env WP_MULTISITE=1 WP_PHPUNIT__TESTS_CONFIG=/wordpress-phpunit/wp-tests-config.php WORDPRESS_TABLE_PREFIX=wptests_ WP_TESTS_DIR=/var/www/wordpress-develop/tests/phpunit /var/www/html/wp-content/plugins/amp/vendor/bin/phpunit -c /var/www/html/wp-content/plugins/amp/phpunit.xml.dist $npm_config_args'",

[thelovekesh]

QA Passed ✅

PHPUnit tests workflow for multisite is up and running with PHP 7.4 and WP latest.

See job or explore the action runs for the Build Test & Measure workflow in the Actions tab.