phpunit test throws error for this plugin

[rezeau]

When running phpunit on my local machine the tests stop with these error messages:

C:\xampp\htdocs\moodle311>php vendor/bin/phpunit
Moodle 3.11.1 (Build: 20210712), 2094d420e1a7966ad091357b53355d7f7cae1031
Php: 7.4.8, mariadb: 10.4.13, OS: Windows NT 10.0 AMD64
PHP Fatal error: Declaration of qbehaviour_adaptivemultipart_mark_display_test::setUp() must be compatible with PHPUnit\Framework\TestCase::setUp(): void in C:\xampp\htdocs\moodle311\question\behaviour\adaptivemultipart\tests\mark_display_test.php on line 52

Fatal error: Declaration of qbehaviour_adaptivemultipart_mark_display_test::setUp() must be compatible with PHPUnit\Framework\TestCase::setUp(): void in C:\xampp\htdocs\moodle311\question\behaviour\adaptivemultipart\tests\mark_display_test.php on line 52