The test suites would be executed repeatedly if the user doesn't specify the test suite in PHPUnit 10.
Please switch the branches and install PHPUnit to see the differences.
$ ./vendor/bin/phpunit -c ./phpunit.xml
PHPUnit 9.6.15 by Sebastian Bergmann and contributors.
Runtime: PHP 8.2.14
Configuration: ./phpunit.xml
... 3 / 3 (100%)
Time: 00:00.005, Memory: 6.00 MB
OK (3 tests, 3 assertions)
$ ./vendor/bin/phpunit -c ./phpunit.xml
PHPUnit 10.5.7 by Sebastian Bergmann and contributors.
Runtime: PHP 8.2.14
Configuration: /<SOME_PATH>/phpunit.xml
... 3 / 3 (100%)
Time: 00:00.003, Memory: 6.00 MB
OK (3 tests, 3 assertions)
$ ./vendor/bin/phpunit -c ./phpunit.xml
PHPUnit 10.5.7 by Sebastian Bergmann and contributors.
Runtime: PHP 8.2.14
Configuration: /<SOME_PATH>/phpunit.xml
...... 6 / 6 (100%)
Time: 00:00.004, Memory: 6.00 MB
OK (6 tests, 6 assertions)