인프런 커뮤니티 질문&답변

package repository;

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

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

import static org.assertj.core.api.Assertions.*;

class MemoryMemberRepositoryTest {
    MemoryMemberRepository repository = new MemoryMemberRepository();

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

    @Test
    public void save() {
//given
        Member member = new Member();
        member.setName("spring");
//when
        repository.save(member);
//then
        Member result = repository.findById(member.getId()).get();
        assertThat(result).isEqualTo(member);
    }

    @Test
    public void findByName() {
//given
        Member member1 = new Member();
        member1.setName("spring1");
        repository.save(member1);
        Member member2 = new Member();
        member2.setName("spring2");
        repository.save(member2);
//when
        Member result = repository.findByName("spring1").get();
        assertThat(result).isEqualTo(member1);
        //then
    }

    @Test
    public void findAll() {
//given
        Member member1 = new Member();
        member1.setName("spring1");
        repository.save(member1);
        Member member2 = new Member();
        member2.setName("spring2");
        repository.save(member2);
//when
        List<Member> result = repository.findAll();
//then
        assertThat(result.size()).isEqualTo(2);
    }
}

package hello.hellospring.repository;

import hello.hellospring.domain.Member;

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

public interface MemberRepository {
    Member save(Member member);
    Optional<Member> findById(Long id);
    Optional<Member> findByName(String name);
    List<Member> findAll();
}

package hello.hellospring.repository;
import hello.hellospring.domain.Member;
import java.util.*;

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

    @Override
    public Member save(Member member) {
        member.setId(++sequence);
        store.put(member.getId(), member);
        return member;
    }
    @Override
    public Optional<Member> findById(Long id) {
        return Optional.ofNullable(store.get(id));
    }
    @Override
    public List<Member> findAll() {
        return new ArrayList<>(store.values());
    }
    @Override
    public Optional<Member> findByName(String name) {
        return store.values().stream()
                .filter(member -> member.getName().equals(name))
                .findAny();
    }
    public void clearStore() {
        store.clear();
    }
}

이렇게 오류가 발생하는데 이유가 뭘까요? 아래와 같이 코드를 수정해보기도 하였습니다만, findAll 과 같이 노란색이 될뿐 초록색 마크가 나오지는 않습니다.

@Test
public void findByName() {
    // given
    Member member1 = new Member();
    member1.setName("spring1");
    repository.save(member1);
    Member member2 = new Member();
    member2.setName("spring2");
    repository.save(member2);
    // when
    Optional<Member> result = repository.findByName("spring1");
    // then
    assertThat(result.isPresent()).isTrue();
    assertThat(result.get()).isEqualTo(member1);
}