트랜잭션 - 적용1

MemberServiceV1

package hello.jdbc.service;

import hello.jdbc.domain.Member;
import hello.jdbc.repository.MemberRepositoryV1;
import lombok.RequiredArgsConstructor;

import java.sql.SQLException;

@RequiredArgsConstructor
public class MemberServiceV1 {

    private final MemberRepositoryV1 memberRepository;

    public void accountTransfer(String fromId, String toId, int money) throws SQLException {

        Member fromMember = memberRepository.findById(fromId);
        Member toMember = memberRepository.findById(toId);

        memberRepository.update(fromId, fromMember.getMoney() - money);
        validation(toMember);
        memberRepository.update(toId, toMember.getMoney() + money);
    }

    private void validation(Member toMember) {
        if (toMember.getMemberId().equals("ex")) {
            throw new IllegalStateException("이체 중 예외 발생");
        }
    }
}

formId 의 회원을 조회해서 toId 의 회원에게 money 만큼의 돈을 계좌이체 하는 로직이다.
▶ fromId 회원의 돈을 money 만큼 감소한다. UPDATE SQL 실행
▶ toId 회원의 돈을 money 만큼 증가한다. UPDATE SQL 실행

예외 상황을 테스트해보기 위해 toId 가 "ex" 인 경우 예외를 발생한다.

 

 

 

MemberServiceV1Test

package hello.jdbc.service;

import hello.jdbc.connection.ConnectionConst;
import hello.jdbc.domain.Member;
import hello.jdbc.repository.MemberRepositoryV1;
import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

import java.sql.SQLException;

import static hello.jdbc.connection.ConnectionConst.*;
import static org.assertj.core.api.Assertions.*;
import static org.junit.jupiter.api.Assertions.*;

class MemberServiceV1Test {

    public static final String MEMBER_A = "memberA";
    public static final String MEMBER_B = "memberB";
    public static final String MEMBER_EX = "ex";

    private MemberRepositoryV1 memberRepository;
    private MemberServiceV1 memberService;

    @BeforeEach
    void before() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource(URL, USERNAME, PASSWORD);
        memberRepository = new MemberRepositoryV1(dataSource);
        memberService = new MemberServiceV1(memberRepository);
    }
    @AfterEach
    void after() throws SQLException {
        memberRepository.delete(MEMBER_A);
        memberRepository.delete(MEMBER_B);
        memberRepository.delete(MEMBER_EX);
    }

    @Test
    @DisplayName("정상 이체")
    void accountTransfer() throws SQLException {
        Member memberA = new Member(MEMBER_A, 10000);
        Member memberB = new Member(MEMBER_B, 10000);
        memberRepository.save(memberA);
        memberRepository.save(memberB);

        memberService.accountTransfer(memberA.getMemberId(), memberB.getMemberId(), 2000);

        Member findMemberA = memberRepository.findById(memberA.getMemberId());
        Member findMemberB = memberRepository.findById(memberB.getMemberId());
        assertThat(findMemberA.getMoney()).isEqualTo(8000);
        assertThat(findMemberB.getMoney()).isEqualTo(12000);
    }

    @Test
    @DisplayName("이체 중 예외 발생")
    void accountTransferEx() throws SQLException {
        Member memberA = new Member(MEMBER_A, 10000);
        Member memberEx = new Member(MEMBER_EX, 10000);
        memberRepository.save(memberA);
        memberRepository.save(memberEx);

        assertThatThrownBy(() -> memberService.accountTransfer(memberA.getMemberId(), memberEx.getMemberId(), 2000))
                .isInstanceOf(IllegalStateException.class);


        Member findMemberA = memberRepository.findById(memberA.getMemberId());
        Member findMemberB = memberRepository.findById(memberEx.getMemberId());
        assertThat(findMemberA.getMoney()).isEqualTo(8000);
        assertThat(findMemberB.getMoney()).isEqualTo(10000);
    }
}

 

 

 

정상이체 - accountTransfer()

 

given: 다음 데이터를 저장해서 테스트를 준비한다.
▶ memberA 10000원
▶ memberB 10000원

when: 계좌이체 로직을 실행한다.
▶ memberService.accountTransfer() 를 실행한다.
▶ memberA memberB 로 2000원 계좌이체 한다.
▶ memberA 의 금액이 2000원 감소한다.
▶ memberB 의 금액이 2000원 증가한다.

then: 계좌이체가 정상 수행되었는지 검증한다.
▶ memberA 8000원 - 2000원 감소
▶ memberB 12000원 - 2000원 증가

 

 

정상이체 로직이 정상 수행되는 것을 확인할 수 있다.

 

 

 

테스트 데이터 제거

테스트가 끝나면 다음 테스트에 영향을 주지 않기 위해 @AfterEach 에서 테스트에 사용한 데이터를 모두 삭제한다.
▶ @BeforeEach : 각각의 테스트가 수행되기 전에 실행된다.
▶ @AfterEach : 각각의 테스트가 실행되고 난 이후에 실행된다.

@AfterEach
void after() throws SQLException {
 memberRepository.delete(MEMBER_A);
 memberRepository.delete(MEMBER_B);
 memberRepository.delete(MEMBER_EX);
}

 

 

 

이체중 예외 발생 - accountTransferEx()

 

given: 다음 데이터를 저장해서 테스트를 준비한다.
▶ memberA 10000원
▶ memberEx 10000원

when: 계좌이체 로직을 실행한다.
▶ memberService.accountTransfer() 를 실행한다.
▶ memberA memberEx 로 2000원 계좌이체 한다.
▶ memberA 의 금액이 2000원 감소한다.
▶ memberEx 회원의 ID는 ex 이므로 중간에 예외가 발생한다. 이 부분이 중요하다.

then: 계좌이체는 실패한다. memberA 의 돈만 2000원 줄어든다.
▶ memberA 8000원 - 2000원 감소
▶ memberB 10000원 - 중간에 실패로 로직이 수행되지 않았다. 따라서 그대로 10000원으로 남아있게 된다.

 

 

 

 

정리

이체중 예외가 발생하게 되면 memberA 의 금액은 10000원 8000원으로 2000원 감소한다. 그런데 memberB 의 돈은 그대로 10000원으로 남아있다. 결과적으로 memberA 의 돈만 2000원 감소한 것이다!

 

 

 

 

 

 

 

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