[BE] fix: 축제 상세 조회 시 공연 목록 시작 시간으로 정렬되도록 수정 (#967) (#968)

fix: 축제 상세 조회 시 공연 목록 정렬 조건 수정

- 식별자 -> 시작 시간

backend/src/main/java/com/festago/festival/repository/FestivalDetailV1QueryDslRepository.java

@@ -64,7 +64,7 @@ public Optional<FestivalDetailV1Response> findFestivalDetail(Long festivalId) {
                             stage.id,
                             stage.startTime,
                             stageQueryInfo.artistInfo
-                        ).skipNulls(), Comparator.comparingLong(StageV1Response::id))
+                        ).skipNulls(), Comparator.comparing(StageV1Response::startDateTime))
                     )
                 )
             );

backend/src/test/java/com/festago/festival/application/integration/query/FestivalDetailV1QueryServiceIntegrationTest.java

@@ -1,5 +1,6 @@
 package com.festago.festival.application.integration.query;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.assertj.core.api.SoftAssertions.assertSoftly;
 
@@ -10,6 +11,7 @@
 import com.festago.festival.application.FestivalDetailV1QueryService;
 import com.festago.festival.domain.Festival;
 import com.festago.festival.dto.SocialMediaV1Response;
+import com.festago.festival.dto.StageV1Response;
 import com.festago.festival.repository.FestivalRepository;
 import com.festago.school.domain.School;
 import com.festago.school.repository.SchoolRepository;
@@ -28,6 +30,7 @@
 import com.festago.support.fixture.StageArtistFixture;
 import com.festago.support.fixture.StageFixture;
 import java.time.LocalDate;
+import java.time.LocalDateTime;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayNameGeneration;
 import org.junit.jupiter.api.DisplayNameGenerator;
@@ -174,6 +177,18 @@ private School createSchool(String schoolName, String domain) {
         });
     }
 
+    @Test
+    void 공연_목록은_공연의_시작_시간_기준으로_정렬된다() {
+        // when
+        var response = festivalDetailV1QueryService.findFestivalDetail(테코대학교_축제.getId());
+
+        // then
+        assertThat(response.stages())
+            .map(StageV1Response::startDateTime)
+            .map(LocalDateTime::toLocalDate)
+            .containsExactly(now, now.plusDays(1), now.plusDays(2));
+    }
+
     @Test
     void 축제에_공연이_없으면_응답의_공연에는_비어있는_컬렉션이_반환된다() {
         // when