Feature/#182 이미 참여한 이벤트인지 확인하는 기능 추가

backend/emm-sale/src/docs/asciidoc/index.adoc

@@ -141,6 +141,14 @@ include::{snippets}/participate-event-cancel/http-request.adoc[]
 .HTTP response
 include::{snippets}/participate-event-cancel/http-response.adoc[]
 
+=== `GET`: Event에 이미 참여한 멤버인지 확인
+
+.HTTP request
+include::{snippets}/check-already-participate/http-request.adoc[]
+
+.HTTP response
+include::{snippets}/check-already-participate/http-response.adoc[]
+
 === `GET`: 행사 목록 조회
 
 .HTTP request

backend/emm-sale/src/main/java/com/emmsale/event/api/EventApi.java

@@ -41,7 +41,7 @@ public ResponseEntity<EventDetailResponse> findEventById(@PathVariable final Lon
   }
 
   @PostMapping("/{eventId}/participants")
-  public ResponseEntity<String> participateEvent(
+  public ResponseEntity<Void> participateEvent(
       @PathVariable final Long eventId,
       @RequestBody final EventParticipateRequest request,
       final Member member
@@ -88,16 +88,24 @@ public EventDetailResponse addEvent(
     return eventService.addEvent(request, LocalDate.now());
   }
 
-  @PutMapping("/{event-id}")
+  @PutMapping("/{eventId}")
   @ResponseStatus(HttpStatus.OK)
-  public EventDetailResponse updateEvent(@PathVariable(name = "event-id") final Long eventId,
+  public EventDetailResponse updateEvent(@PathVariable final Long eventId,
       @RequestBody @Valid final EventDetailRequest request) {
     return eventService.updateEvent(eventId, request, LocalDate.now());
   }
 
-  @DeleteMapping("/{event-id}")
+  @DeleteMapping("/{eventId}")
   @ResponseStatus(HttpStatus.NO_CONTENT)
-  public void deleteEvent(@PathVariable(name = "event-id") final Long eventId) {
+  public void deleteEvent(@PathVariable final Long eventId) {
     eventService.deleteEvent(eventId);
   }
+
+  @GetMapping("/{eventId}/participants/already-participate")
+  public ResponseEntity<Boolean> isAlreadyParticipate(
+      @PathVariable final Long eventId,
+      @RequestParam(name = "member-id") final Long memberId
+  ) {
+    return ResponseEntity.ok(eventService.isAlreadyParticipate(eventId, memberId));
+  }
 }

backend/emm-sale/src/main/java/com/emmsale/event/application/EventService.java

@@ -249,4 +249,8 @@ private List<Tag> findAllPersistTagsOrElseThrow(final List<TagRequest> tags) {
             .orElseThrow(() -> new EventException(EventExceptionType.NOT_FOUND_TAG)))
         .collect(toList());
   }
+
+  public Boolean isAlreadyParticipate(final Long eventId, final Long memberId) {
+    return participantRepository.existsByEventIdAndMemberId(eventId, memberId);
+  }
 }

backend/emm-sale/src/main/java/com/emmsale/event/domain/repository/ParticipantRepository.java

@@ -9,4 +9,6 @@
 public interface ParticipantRepository extends JpaRepository<Participant, Long> {
 
   Optional<Participant> findByMemberIdAndEventId(final Long memberId, final Long eventId);
+
+  Boolean existsByEventIdAndMemberId(final Long eventId, final Long memberId);
 }

backend/emm-sale/src/main/resources/http/event.http

@@ -46,3 +46,6 @@ Authorization: bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxIiwiaWF0IjoxNjkwMTk2OTY5L
 
 ### 행사 참여자 목록 조회
 GET http://localhost:8080/events/1/participants
+
+### 멤버가 행사에 참여했는지 확인
+GET http://localhost:8080/events/1/participants/already-participate?member-id=1

backend/emm-sale/src/test/java/com/emmsale/event/api/EventApiTest.java

@@ -4,6 +4,7 @@
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyLong;
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.when;
 import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.document;
@@ -448,4 +449,20 @@ void addEventWithUnformattedEndDateTimeTest(final String endDateTime) throws Exc
       result.andExpect(status().isBadRequest());
     }
   }
+
+  @Test
+  @DisplayName("이미 Event에 멤버가 참여헀는지 확인할 수 있다.")
+  void isAlreadyParticipate() throws Exception {
+    //given
+    final Long memberId = 2L;
+    final Long eventId = 3L;
+    given(eventService.isAlreadyParticipate(eventId, memberId)).willReturn(true);
+
+    //when && then
+    mockMvc.perform(
+            get("/events/{eventId}/participants/already-participate?member-id={memberId}"
+                , eventId, memberId)
+        )
+        .andDo(document("check-already-participate"));
+  }
 }

backend/emm-sale/src/test/java/com/emmsale/event/application/EventServiceTest.java

@@ -19,6 +19,7 @@
 import static com.emmsale.event.exception.EventExceptionType.NOT_FOUND_PARTICIPANT;
 import static com.emmsale.event.exception.EventExceptionType.NOT_FOUND_TAG;
 import static com.emmsale.event.exception.EventExceptionType.START_DATE_TIME_AFTER_END_DATE_TIME;
+import static com.emmsale.member.MemberFixture.memberFixture;
 import static com.emmsale.tag.TagFixture.AI;
 import static com.emmsale.tag.TagFixture.IOS;
 import static com.emmsale.tag.TagFixture.백엔드;
@@ -804,5 +805,38 @@ void deleteEventWithNotExistsEventTest() {
     }
   }
 
+  @Nested
+  @DisplayName("이벤트에 이미 참가한 멤버인지 확인할 수 있다.")
+  class isAlreadyParticipate {
+
+    @Test
+    @DisplayName("이벤트에 이미 참가한 경우 true를 반환한다.")
+    void alreadyParticipateThenTrue() {
+      //given
+      final Event 인프콘 = eventRepository.save(인프콘_2023());
+      final Member 멤버 = memberRepository.save(memberFixture());
+      eventService.participate(인프콘.getId(), 멤버.getId(), 멤버);
+
+      //when
+      final Boolean actual = eventService.isAlreadyParticipate(인프콘.getId(), 멤버.getId());
+
+      //then
+      assertThat(actual).isTrue();
+    }
+
+    @Test
+    @DisplayName("이벤트에 참가히자 않은 경우 false를 반환한다.")
+    void isNotAlreadyParticipateThenFalse() {
+      //given
+      final Event 인프콘 = eventRepository.save(인프콘_2023());
+      final Member 멤버 = memberRepository.save(memberFixture());
+
+      //when
+      final Boolean actual = eventService.isAlreadyParticipate(인프콘.getId(), 멤버.getId());
+
+      //then
+      assertThat(actual).isFalse();
+    }
+  }
 }
 

backend/emm-sale/src/test/java/com/emmsale/event/domain/repository/ParticipantRepositoryTest.java

@@ -0,0 +1,67 @@
+package com.emmsale.event.domain.repository;
+
+import static com.emmsale.event.EventFixture.인프콘_2023;
+import static com.emmsale.member.MemberFixture.memberFixture;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.emmsale.event.domain.Event;
+import com.emmsale.event.domain.Participant;
+import com.emmsale.member.domain.Member;
+import com.emmsale.member.domain.MemberRepository;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase.Replace;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.test.context.jdbc.Sql;
+
+@Sql("/data-test.sql")
+@AutoConfigureTestDatabase(replace = Replace.NONE)
+@DataJpaTest
+class ParticipantRepositoryTest {
+
+  @Autowired
+  private ParticipantRepository participantRepository;
+  @Autowired
+  private MemberRepository memberRepository;
+  @Autowired
+  private EventRepository eventRepository;
+
+  @Nested
+  @DisplayName("eventId와 memberId로 Participant가 존재하는 지 확인할 수 있다.")
+  class ExistsByEventIdAndMemberId {
+
+    @Test
+    @DisplayName("Participant가 존재하는 경우 true를 반환한다.")
+    void alreadyParticipateThenTrue() {
+      //given
+      final Event 인프콘 = eventRepository.save(인프콘_2023());
+      final Member 멤버 = memberRepository.save(memberFixture());
+      participantRepository.save(new Participant(멤버, 인프콘));
+
+      //when
+      final Boolean actual = participantRepository.existsByEventIdAndMemberId(인프콘.getId(),
+          멤버.getId());
+
+      //then
+      assertThat(actual).isTrue();
+    }
+
+    @Test
+    @DisplayName("Particpant가 존재하지 않는 false를 반환한다.")
+    void isNotAlreadyParticipateThenFalse() {
+      //given
+      final Event 인프콘 = eventRepository.save(인프콘_2023());
+      final Member 멤버 = memberRepository.save(memberFixture());
+
+      //when
+      final Boolean actual = participantRepository.existsByEventIdAndMemberId(인프콘.getId(),
+          멤버.getId());
+
+      //then
+      assertThat(actual).isFalse();
+    }
+  }
+}