[스프링 입문] 회원 서비스 테스트

테스트 케이스 단축키 : 테스트를 만들고 싶은 클래스에 들어간 후 Ctrl + Alt + t

회원 서비스 테스트 코드

package hello.hellospring.service;

import hello.hellospring.domain.Member;
import hello.hellospring.repository.MemoryMemberRepository;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;


import java.util.List;
import java.util.Optional;

import static org.assertj.core.api.Assertions.*;
import static org.junit.jupiter.api.Assertions.assertThrows;

class MemberServiceTest {
    MemoryMemberRepository memberRepository;
    MemberService memberService;

    @BeforeEach
    public void beforeEach() {
        memberRepository = new MemoryMemberRepository();
        memberService = new MemberService(memberRepository);
    }

    @AfterEach
    public void afterEach() {
        memberRepository.clearStore();
    }

    @Test
    void 회원가입() {
        //given
        Member member = new Member();
        member.setName("spring");
        //when
        Long saveId = memberService.join(member);
        //then
        Member findMember = memberService.findOne(saveId).get();
        assertThat(member.getName()).isEqualTo(findMember.getName());
    }

    @Test
    public void 중복_회원_예외() {
        //given
        Member member1 = new Member();
        member1.setName("spring");

        Member member2 = new Member();
        member2.setName("spring");

        //when
        memberService.join(member1);
        IllegalStateException e = assertThrows(IllegalStateException.class, () -> memberService.join(member2));

        //then
        assertThat(e.getMessage()).isEqualTo("이미 존재하는 회원입니다.");
    }

    @Test
    void findMembers() {
        //given
        Member member1 = new Member();
        member1.setName("spring");

        Member member2 = new Member();
        member2.setName("spring2");
        //when
        memberService.join(member1);
        memberService.join(member2);
        List<Member> members = memberService.findMembers();
        //then
        assertThat(members).contains(member1, member2);
    }

    @Test
    void findOne() {
        //given
        Member member1 = new Member();
        member1.setName("hello");
        Member member2 = new Member();
        member2.setName("spring");

        //when
        Long saveId = memberService.join(member1);
        Long saveId2 =  memberService.join(member2);
        Member findMember = memberService.findOne(saveId).get();
        //then
        assertThat(findMember.getName()).isEqualTo("hello");
    }
}

테스트 케이스 작성 Tip

1. 테스트 코드명은 한글로 적는 것이 더 직관적일 수 있다.
2. (given: 주어졌을 때, when : 실행했을 때, then : 결과) 를 사용하여 가시성을 높인다.
3. 예외가 발생 테스트 시 try - catch 대신 assertThrows 문법 사용

DI (Dependency Injection) 의존성 주입

public class MemberService {
    private final MemberRepository memberRepository;

    public MemberService(MemberRepository memberRepository) {  // 외부에서 주입
        this.memberRepository = memberRepository;
    }

class MemberServiceTest {
    MemoryMemberRepository memberRepository;
    MemberService memberService;

    @BeforeEach
    public void beforeEach() {
        memberRepository = new MemoryMemberRepository();
        memberService = new MemberService(memberRepository);
    }

• 사용 이유

class MemberServiceTest {
	MemberServiceTest memberService = new MemberService();
    	MemoryMemberRepository memberRepository = new MemoryMemberRepository();
        ...
}

public class MemberService{
	private final MemberRepository memberRepository = new MemoryMemberRepository();
    
    ...
}

public class MemoryMemberRepository implements MemberRepository {
    private static Map<Long,Member> store = new HashMap<>();
    private static long sequence = 0L;
    ...

서비스 테스트에서 필요에 의해 new MemoryMemberRepository를 만든다.
서비스 테스트에서 new MemberService()에서도 new MemoryMemberRepository를 만든다.
즉 2개의 MemoryMemberRepository를 사용하고 있는 것이다.
저장소인 store가 static 변수가 아니면 2개의 서로 다른 db를 가지고 테스트하는 꼴이 된다.

BeforeEach

각 테스트 실행할때 마다 그전에 1회 실행된다.