Exemplo completo do descrito acima:

import org.junit.Test;
import static org.junit.Assert.assertEquals;

public class TabNewsExercise1Test {

    @Test
    public void test1() {
        TabNewsExercise1 ex = new TabNewsExercise1();
        assertEquals(5, ex.doExercise("teste"));
    }

    @Test
    public void test2() {
        TabNewsExercise1 ex = new TabNewsExercise1();
        assertEquals(14, ex.doExercise("Iuri"));
    }

    @Test
    public void test3() {
        TabNewsExercise1 ex = new TabNewsExercise1();
        assertEquals(16, ex.doExercise("tabnews"));
    }

}

public class TabNewsExercise1 {

    public static int doExercise(final String input) {
        int score = 0;

        for (char letter : input.toUpperCase().toCharArray()) {
            score += Letters.valueOf(Character.toString(letter)).getLetterScore();
        }
        return score;
    }

}

public enum Letters {
    A(1),
    B(3),
    C(3),
    D(2),
    E(1),
    F(4),
    G(2),
    H(4),
    I(5),
    J(8),
    K(5),
    L(1),
    M(3),
    N(5),
    O(1),
    P(3),
    Q(10),
    R(1),
    S(1),
    T(1),
    U(3),
    V(4),
    W(4),
    X(8),
    Y(4),
    Z(10);

    private final int score;

    private Letters(int letterScore) {
        this.score = letterScore;
    }

    int getLetterScore() {
        return score;
    }
}