PHPUnit 13.4 - #[Group] attribute is ignored deprecation

Problem/Motivation

Since PHPUnit 13.4, a number of tests are failing with a PHPUnit test runner deprecation

Class-level #[Group] attribute on Drupal\Tests\Core\Routing\UrlGeneratorTest is ignored, but will be inherited by its subclasses in PHPUnit 14

Steps to reproduce

Run tests under PHPUnit, see #3574681: [Nov 2026] Introduce support for PHPUnit 13.5.

Proposed resolution

Figure out what is the cause and try to fix.

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet