distinct 테스트코드 관련 질문 드립니다.

    @Test
    public void distinct() {

        em.persist(new Member("member1"));
        em.persist(new Member("member2"));
        em.persist(new Member("member2"));
        em.persist(new Member("member5"));

        List<String> usernames = queryFactory
                .select(member.username).distinct()
                .from(member)
                .fetch();

        assertThat(usernames)
                .containsExactly("member1", "member2", "member3", "member4", "member5");
    }

테스트코드 직접 짜본 경험이 별로 없어서 그런데

이렇게 짜면 되는걸까요 ...?