인프런 커뮤니티 질문&답변

@Service
@RequiredArgsConstructor
public class MemberService {
    private final MemberRepository memberRepository;

    @Transactional
    public void signUp(Member member){
        memberRepository.save(member);
    }

    public Member findOne(Long id){
        return memberRepository.findById(id).orElseThrow();
    }

}

@Test
void signUp() {
    Member member1 = Member.builder()
            .userId("user1")
            .birthDay(LocalDate.now())
            .password("pass")
            .email("aa@bb.cc")
            .build();

    memberService.signUp(member1);

    Member member2 = memberService.findOne(member1.getId());

    assertThat(member1).isEqualTo(member2);
}

트랙잰션이 Memberservice에서 signUp을 완료 하고 트랜잭션이 끝난다고 영속성 컨텍스트가 비워지지 않다고 이해 했는데 왜 같은 id 값으로 다시 찾을 때 동일성을 보장하지 않는걸까요?