외부 트랜잭션에서 isNewTransaction이 false로 나오는거에 대해 질문드립니다

@SpringBootTest
class MemberServiceTest {
    @Autoworied lateinit var memberService: MembersService

    @Test
    fun get() {
        memberService.get(1L)
    }

}

@Service
class MemberService(
    private val txManager: PlatformTransactionManager,
) {
    
    @Transactional(readOnly = true)
    fun get(id: Long) {
        val tx = txManager.getTransaction(DefaultTransactionAttribute())
        println("isCurrentTransactionReadOnly()=${TransactionSynchronizationManager.isCurrentTransactionReadOnly()}")
        println("isActualTransactionActive()=${TransactionSynchronizationManager.isActualTransactionActive()}")
        println("isNewTransaction()=${tx.isNewTransaction()}")
        
        // get
    }
}

제가 기대한건

isNewTransaction = true

인데요 -> 가장 처음 호출된 @Transactional이 있는 service 메서드이기 때문에

그런데

테스트 코드로 실행해도 그렇고, API로 get 메서드가 호출되도록 해봐도 그렇고

모두 isNewTransaction = false 로 나옵니다.

내부 트랜잭션이 아니라 외부 트랜잭션이라고 생각했는데 왜 false일까요....

09:54:40.059 [Test worker] DEBUG o.s.o.j.JpaTransactionManager - Creating new transaction with name [com.application.service.member.MemberService.get]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly
09:54:40.062 [Test worker] DEBUG o.s.o.j.JpaTransactionManager - Opened new EntityManager [SessionImpl(16208286<open>)] for JPA transaction 
09:54:40.075 [Test worker] DEBUG o.h.e.t.i.TransactionImpl - On TransactionImpl creation, JpaCompliance#isJpaTransactionComplianceEnabled == false 
09:54:40.075 [Test worker] DEBUG o.h.e.t.i.TransactionImpl - begin 
09:54:40.081 [Test worker] DEBUG o.s.o.j.JpaTransactionManager - Exposing JPA transaction as JDBC [org.springframework.orm.jpa.member.HibernateJpaDialect$HibernateConnectionHandle@486e4af6] 
09:54:40.083 [Test worker] TRACE o.s.t.i.TransactionInterceptor - Getting transaction for [com.application.service.member.MemberService.get] 
09:54:40.084 [Test worker] DEBUG o.s.o.j.JpaTransactionManager - Found thread-bound EntityManager [SessionImpl(16208286<open>)] for JPA transaction 
09:54:40.084 [Test worker] DEBUG o.s.o.j.JpaTransactionManager - Participating in existing transaction 
TransactionSynchronizationManager.isCurrentTransactionReadOnly()=true
TransactionSynchronizationManager.isActualTransactionActive()=true
outer.isNewTransaction()=false

Creating new transaction with name

이 나오는데

09:54:40.084 [Test worker] DEBUG o.s.o.j.JpaTransactionManager - Participating in existing transaction 

이 로그도 나옵니다,,