add phpunit/phpunit as a development dependency

[rfalkenstein]

This PR proposes to add phpunit/phpunit (^13.0) as a composer development dependency. The dependency was already used in ILIAS 11 and below.

Description:
The PHPUnit dependency is used to run unit tests.

Reason to introduce this dependency:
The PHPUnit dependency phpunit/phpunit is the standard framework to run unit tests in PHP. It is developed by Sebastian Bergmann, well maintained with regular commits and lists about 900 million installs on packagist. As of today we consider this as the de facto standard for php Unit testing and thus would like to introduce this development dependency into the next ILIAS release.

Version: ^13.0
Licence: BSD 3
Type of dependency: composer
Dev-Dependency: yes

Vendor information:

Packagist/NPM: https://packagist.org/packages/phpunit/phpunit
Github: https://github.com/sebastianbergmann/phpunit
Vendor Homepage: https://phpunit.de/index.html

Dep consolidation PR: #11255

[matthiaskunkel]

Jour Fixe, 13 APR 2026: Dependency is accepted for ILIAS 12.

[lscharmer]

Hi,
this PR proposes PHPUnit as a dev dependency but it is still used in prod inside the setup process: https://github.com/ILIAS-eLearning/ILIAS/blob/trunk/components/ILIAS/Component/src/Dependencies/Reader.php#L355

This will result in the same issue as addressed in PR #10532.

Either this dependency must be changed to a prod dependency or the usage of PHPUnit in the setup must be removed.

[mjansenDatabay]

Hi, this PR proposes PHPUnit as a dev dependency but it is still used in prod inside the setup process: https://github.com/ILIAS-eLearning/ILIAS/blob/trunk/components/ILIAS/Component/src/Dependencies/Reader.php#L355

This will result in the same issue as addressed in PR #10532.

Either this dependency must be changed to a prod dependency or the usage of PHPUnit in the setup must be removed.

This will be addressed by #11329