I don't know if this is bugs in our code, or in core PHP unit. Anyway, these options should do useful things. E.g. --debug outputs the name of each test before running it, which is helpful when you get weird crashes, but adding that has no effect when running the Moodle tests.

I think this may acutally be a core PHPunit bug. If you look at https://github.com/sebastianbergmann/phpunit/blob/master/PHPUnit/TextUI/Command.php#L740, it does not pass any of the options to the printer class constructor, and I cannot see any other way for those options to be set.