memberRepository 중 findByName 테스트 오류

[질문 템플릿]
1. 강의 내용과 관련된 질문인가요? (예/아니오)
2. 인프런의 질문 게시판과 자주 하는 질문에 없는 내용인가요? (예/아니오)
3. 질문 잘하기 메뉴얼을 읽어보셨나요? (예/아니오)

[질문 내용]
service test하려다가 join에서 오류나서 repository부터 다시 test하는데

@Repository
@RequiredArgsConstructor
public class MemberRepository {

    private final EntityManager em;
    
    public void save(Member member) {
        em.persist(member);
    }

    public Member findOne(Long id) {
        return em.find(Member.class, id);
    }

    public List<Member> findAll() {
        return em.createQuery("select m from Member m", Member.class).getResultList();
    }

    public List<Member> findByName(String name) {
        return em.createQuery("select m from Member m where m.name = :name", Member.class)
                .setParameter("name", name)
                .getResultList();
    }


}

@Service
@RequiredArgsConstructor
@Transactional
public class MemberService {

    private final MemberRepository memberRepository;

    public Long join(Member member) {
        validateDuplicateMember(member); //회원이름 중복인지 검증
            memberRepository.save(member);
        return member.getId();
    }

    //회원이름 중복검사
    public void validateDuplicateMember(Member member) {
        List<Member> findMember = memberRepository.findByName(member.getUsername());
        if (findMember.size() > 0) {
            throw new IllegalStateException("중복된 이름이 있습니다.");
        }
    }

@SpringBootTest
@RunWith(SpringRunner.class)
@Transactional
public class MemberServiceTest {
    @Autowired
    MemberService memberService;
    @Autowired
    MemberRepository memberRepository;
    @Autowired
    EntityManager em;

    @Test
    @Rollback(false)
    public void join() {
        Member memberA = new Member();
        memberA.setUsername("memberA");
        memberRepository.save(memberA);
        List<Member> findMember = memberRepository.findAll();//통과
            memberRepository.findByName(memberA.getUsername());

    }
}