Ah ah, content que tu y sois arrivé !

The validating tests are not meant to be executed that way.
The fact that tests can't be executed that way could be intentional :). Maybe you should try clicking another button.
There's a lot of katas in codewars that work that way.
See Secret knock for a similarly disturbing kata.

Don't understand the question, sorry.

I don't understand your output problem. If I submit this code :

public class Guesser {
    public void guess() {
        System.out.println(LittleClass.class.getName());
        LittleClass.isMySecret("thatILoveUnicorns");
    }
}

It returns me the expected output :

test(GuesserTest)
LittleClass
Try again
Unknown error

You don't have to worry about the Unknown error, the important part is that LittleClass is displayed.

I understand it can be frustrating. But it is meant to be :). I think you're not far from the solution. I hope you'll find it.

Lol, Thx

Thank you, I'm a noob and tried import List without success. Forgot to prefix with "Data."

Is List (List.sort) available ?

Nice but I found it overeasy for a 4kyu kata.