service/src/main/kotlin/com/sangdol/roomescape/theme/infrastructure/persistence/ThemeRepository.kt

@@ -32,10 +32,9 @@ interface ThemeRepository : JpaRepository<ThemeEntity, Long> {
                     AND (s.date BETWEEN :startFrom AND :endAt)
                 GROUP BY 
                     s.theme_id  
-                ORDER BY 
-                    reservation_count desc 
                 LIMIT :count
             ) ranked_themes ON t.id = ranked_themes.theme_id
+            ORDER BY ranked_themes.reservation_count DESC, t.id ASC
         """,
         nativeQuery = true
     )

service/src/test/kotlin/com/sangdol/roomescape/theme/ThemeApiTest.kt

@@ -4,14 +4,15 @@ import com.sangdol.common.types.web.HttpStatus
 import com.sangdol.common.utils.KoreaDate
 import com.sangdol.roomescape.supports.*
 import com.sangdol.roomescape.theme.business.DateUtils
+import com.sangdol.roomescape.theme.dto.ThemeInfoResponse
 import com.sangdol.roomescape.theme.exception.ThemeErrorCode
 import com.sangdol.roomescape.theme.infrastructure.persistence.ThemeEntity
 import com.sangdol.roomescape.theme.infrastructure.persistence.ThemeRepository
-import com.sangdol.roomescape.theme.dto.ThemeInfoResponse
 import com.sangdol.roomescape.theme.mapper.toEntity
 import com.sangdol.roomescape.user.infrastructure.persistence.UserEntity
 import io.kotest.matchers.collections.shouldContainInOrder
 import io.kotest.matchers.collections.shouldHaveSize
+import io.kotest.matchers.comparables.shouldBeLessThan
 import org.hamcrest.CoreMatchers.equalTo
 import org.springframework.http.HttpMethod
 import java.time.LocalDate
@@ -72,6 +73,35 @@ class ThemeApiTest(
                     response.map { it.id }.shouldContainInOrder(expectedResult)
                 }
             }
+
+            test("예약 수가 동일한 경우 ID 오름차순으로 정렬한다.") {
+                val expectedSize = initialize("두 개의 테마에 각각 1개의 확정 예약 생성") {
+                    val user = testAuthUtil.defaultUserLogin()
+                    (1..2).map { _ ->
+                        dummyInitializer.createConfirmReservation(
+                            user.first,
+                            scheduleRequest = ScheduleFixture.createRequest.copy(
+                                date = DateUtils.getSundayOfPreviousWeek(KoreaDate.today())
+                            )
+                        )
+                    }
+                }.size
+
+                runTest(
+                    on = {
+                        get("/themes/most-reserved?count=10")
+                    },
+                    expect = {
+                        statusCode(HttpStatus.OK.value())
+                    }
+                ).also { res ->
+                    val response: List<ThemeInfoResponse> =
+                        ResponseParser.parseListResponse(res.extract().path("data.themes"))
+
+                    response shouldHaveSize expectedSize
+                    response[0].id shouldBeLessThan response[1].id
+                }
+            }
         }
     }