Testing Craft CMS Plugins with Pest

Reference for testing Craft CMS 5 plugins and modules with Pest, primarily via markhuot/craft-pest-core.

The dominant failure mode in Craft plugin testing is not a wrong assertion — it's a suite that writes to a database it shouldn't, or that passes only because of ambient state on the developer's install. Both are silent. Both look like a green suite. This skill leads with isolation for that reason: get the harness right first, then write tests.

Verified against markhuot/craft-pest-core 3.2.2 and craftcms/cms 5.10.12 (August 2026). Where a claim names a class or method, it was read in that package's source. craft-pest's own README and docs are not authoritative on these points — several of the behaviors below are unstated there.

Companion Skills — Load When Needed

• craftcms — Plugin/module architecture, elements, controllers, events, project config. Load when the code under test is being written or changed, not just exercised.
• craft-php-guidelines — PHP standards for the test files themselves (PHPDocs, naming, ECS).
• ddev — Every command runs through DDEV. Load for the correct invocation of a plugin's own suite inside a host project (ddev exec --dir …).

Documentation

• Craft Pest: https://craft-pest.com
• Pest PHP: https://pestphp.com/docs/installation
• Codeception (Craft's native harness): https://craftcms.com/docs/5.x/extend/testing.html