How to test custom validation rules in Laravel 5?

I created a custom validation rule in Laravel, extending it in the register() method of a service provider, and I'd like to test it, but don't know how.

I took a look at Laravel framework's validation tests, but I couldn't understand the purpose of the getTranslator() and getRealTranslator() methods.

Could someone give me a hint on how to test Laravel's custom validation rules?

Thanks!