🚀 1단계 - 레거시 코드 리팩터링

src/main/java/nextstep/qna/domain/Answer.java

@@ -1,5 +1,6 @@
 package nextstep.qna.domain;
 
+import nextstep.qna.CannotDeleteException;
 import nextstep.qna.NotFoundException;
 import nextstep.qna.UnAuthorizedException;
 import nextstep.users.domain.NsUser;
@@ -76,4 +77,11 @@ public void toQuestion(Question question) {
     public String toString() {
         return "Answer [id=" + getId() + ", writer=" + writer + ", contents=" + contents + "]";
     }
+
+    public Answer delete(NsUser writer) throws CannotDeleteException {
+        if (!this.isOwner(writer)) {
+            throw new CannotDeleteException("다른 사람이 쓴 답변이 있어 삭제할 수 없습니다.");
+        }
+        return this.setDeleted(true);
+    }
 }

src/main/java/nextstep/qna/domain/Question.java

@@ -1,5 +1,6 @@
 package nextstep.qna.domain;
 
+import nextstep.qna.CannotDeleteException;
 import nextstep.users.domain.NsUser;
 
 import java.time.LocalDateTime;
@@ -89,4 +90,11 @@ public List<Answer> getAnswers() {
     public String toString() {
         return "Question [id=" + getId() + ", title=" + title + ", contents=" + contents + ", writer=" + writer + "]";
     }
+
+    public Question delete(NsUser writer) throws CannotDeleteException {
+        if (!this.isOwner(writer)) {
+            throw new CannotDeleteException("질문을 삭제할 권한이 없습니다.");
+        }
+        return this.setDeleted(true);
+    }
 }

src/main/java/nextstep/qna/service/DeleteHistoryService.java

@@ -1,7 +1,12 @@
 package nextstep.qna.service;
 
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import nextstep.qna.domain.Answer;
+import nextstep.qna.domain.ContentType;
 import nextstep.qna.domain.DeleteHistory;
 import nextstep.qna.domain.DeleteHistoryRepository;
+import nextstep.qna.domain.Question;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Propagation;
 import org.springframework.transaction.annotation.Transactional;
@@ -18,4 +23,17 @@ public class DeleteHistoryService {
     public void saveAll(List<DeleteHistory> deleteHistories) {
         deleteHistoryRepository.saveAll(deleteHistories);
     }
+
+    public void saveAll(Question question, List<Answer> answers) {
+        List<DeleteHistory> deleteHistories = new ArrayList<>();
+        deleteHistories.add(
+            new DeleteHistory(ContentType.QUESTION, question.getId(), question.getWriter(),
+                LocalDateTime.now()));
+        for (Answer answer : answers) {
+            deleteHistories.add(
+                new DeleteHistory(ContentType.ANSWER, answer.getId(), answer.getWriter(),
+                    LocalDateTime.now()));
+        }
+        this.saveAll(deleteHistories);
+    }
 }

src/main/java/nextstep/qna/service/QnAService.java

@@ -1,19 +1,21 @@
 package nextstep.qna.service;
 
+import java.util.List;
+import java.util.stream.Collectors;
+import javax.annotation.Resource;
 import nextstep.qna.CannotDeleteException;
 import nextstep.qna.NotFoundException;
-import nextstep.qna.domain.*;
+import nextstep.qna.domain.Answer;
+import nextstep.qna.domain.AnswerRepository;
+import nextstep.qna.domain.Question;
+import nextstep.qna.domain.QuestionRepository;
 import nextstep.users.domain.NsUser;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
-import javax.annotation.Resource;
-import java.time.LocalDateTime;
-import java.util.ArrayList;
-import java.util.List;
-
 @Service("qnaService")
 public class QnAService {
+
     @Resource(name = "questionRepository")
     private QuestionRepository questionRepository;
 
@@ -25,25 +27,18 @@ public class QnAService {
 
     @Transactional
     public void deleteQuestion(NsUser loginUser, long questionId) throws CannotDeleteException {
-        Question question = questionRepository.findById(questionId).orElseThrow(NotFoundException::new);
-        if (!question.isOwner(loginUser)) {
-            throw new CannotDeleteException("질문을 삭제할 권한이 없습니다.");
-        }
-
-        List<Answer> answers = question.getAnswers();
-        for (Answer answer : answers) {
-            if (!answer.isOwner(loginUser)) {
-                throw new CannotDeleteException("다른 사람이 쓴 답변이 있어 삭제할 수 없습니다.");
+        Question deletedQuestion = questionRepository.findById(questionId)
+            .orElseThrow(NotFoundException::new)
+            .delete(loginUser);
+
+        List<Answer> deletedAnswers = deletedQuestion.getAnswers().stream().map(answer -> {
+            try {
+                return answer.delete(loginUser);
+            } catch (CannotDeleteException e) {
+                throw new RuntimeException(e);
             }
-        }
-
-        List<DeleteHistory> deleteHistories = new ArrayList<>();
-        question.setDeleted(true);
-        deleteHistories.add(new DeleteHistory(ContentType.QUESTION, questionId, question.getWriter(), LocalDateTime.now()));
-        for (Answer answer : answers) {
-            answer.setDeleted(true);
-            deleteHistories.add(new DeleteHistory(ContentType.ANSWER, answer.getId(), answer.getWriter(), LocalDateTime.now()));
-        }
-        deleteHistoryService.saveAll(deleteHistories);
+        }).collect(Collectors.toList());
+
+        deleteHistoryService.saveAll(deletedQuestion, deletedAnswers);
     }
 }

src/test/java/nextstep/qna/domain/AnswerTest.java

@@ -1,8 +1,37 @@
 package nextstep.qna.domain;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatNoException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import nextstep.qna.CannotDeleteException;
+import nextstep.users.domain.NsUser;
 import nextstep.users.domain.NsUserTest;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
 
 public class AnswerTest {
-    public static final Answer A1 = new Answer(NsUserTest.JAVAJIGI, QuestionTest.Q1, "Answers Contents1");
-    public static final Answer A2 = new Answer(NsUserTest.SANJIGI, QuestionTest.Q1, "Answers Contents2");
+
+    public static final Answer A1 = new Answer(NsUserTest.JAVAJIGI, QuestionTest.Q1,
+        "Answers Contents1");
+    public static final Answer A2 = new Answer(NsUserTest.SANJIGI, QuestionTest.Q1,
+        "Answers Contents2");
+
+    @DisplayName("답변 등록자와 로그인 유저가 일치할 땐 예외를 던지지 않습니다.")
+    @Test
+    void doesNotTrowExceptionWhenDeleteLoginUserMatchedWithAnswerWriter() {
+        NsUser writer = A1.getWriter();
+        assertThatNoException().isThrownBy(() -> A1.delete(writer));
+        assertThat(A1.isDeleted()).isTrue();
+    }
+
+    @DisplayName("답변 등록자와 로그인 유저가 일치하지 않은데 삭제하려고 하면 예외를 던집니다.")
+    @Test
+    void throwExceptionWhenDeleteLoginUserDoesNotMatchedWithAnswerWriter() {
+        NsUser writer = A1.getWriter();
+        assertThatThrownBy(() -> A2.delete(writer)).isInstanceOf(CannotDeleteException.class);
+        assertThat(A2.isDeleted()).isFalse();
+    }
+
+
 }

src/test/java/nextstep/qna/domain/QuestionTest.java

@@ -1,8 +1,35 @@
 package nextstep.qna.domain;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatNoException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import nextstep.qna.CannotDeleteException;
+import nextstep.users.domain.NsUser;
 import nextstep.users.domain.NsUserTest;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
 
 public class QuestionTest {
+
     public static final Question Q1 = new Question(NsUserTest.JAVAJIGI, "title1", "contents1");
     public static final Question Q2 = new Question(NsUserTest.SANJIGI, "title2", "contents2");
+
+    @DisplayName("삭제할 권한이 있다면 질문이 삭제됩니다.")
+    @Test
+    void canDeleteIfYouHavePermission() throws CannotDeleteException {
+        NsUser writer = Q1.getWriter();
+        assertThatNoException().isThrownBy(() -> Q1.delete(writer));
+        assertThat(Q1.isDeleted()).isTrue();
+    }
+
+    @DisplayName("삭제할 권한이 없다면 질문을 삭제할 수 없습니다.")
+    @Test
+    void canNotDeleteIfYouDontHavePermission() throws CannotDeleteException {
+        NsUser writer = Q1.getWriter();
+        assertThatThrownBy(() -> Q2.delete(writer)).isInstanceOf(CannotDeleteException.class);
+        assertThat(Q2.isDeleted()).isFalse();
+    }
+
 }