[fix] /missions/current 신규 유저 500(USER_LEVEL_NOT_FOUND) 해결

src/main/kotlin/com/didit/adapter/webapi/achievement/MissionApi.kt

@@ -24,7 +24,10 @@ class MissionApi(
     @GetMapping("/current")
     fun getCurrentMission(
         @CurrentUserId userId: UUID,
-    ): SuccessResponse<CurrentMissionResponse> = SuccessResponse.of(missionFinder.getCurrentMission(userId))
+    ): SuccessResponse<CurrentMissionResponse> {
+        userMissionRegister.ensureInitialized(userId)
+        return SuccessResponse.of(missionFinder.getCurrentMission(userId))
+    }
 
     @RequireAuth
     @ResponseStatus(HttpStatus.NO_CONTENT)

src/main/kotlin/com/didit/application/achievement/UserMissionService.kt

@@ -3,8 +3,11 @@ package com.didit.application.achievement
 import com.didit.application.achievement.exception.CurrentMissionNotFoundException
 import com.didit.application.achievement.provided.UserMissionRegister
 import com.didit.application.achievement.required.MissionRepository
+import com.didit.application.achievement.required.UserLevelRepository
 import com.didit.application.achievement.required.UserMissionRepository
 import com.didit.domain.achievement.MissionType
+import com.didit.domain.achievement.UserLevel
+import com.didit.domain.achievement.UserMission
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
 import java.time.LocalDateTime
@@ -15,7 +18,20 @@ import java.util.UUID
 class UserMissionService(
     private val userMissionRepository: UserMissionRepository,
     private val missionRepository: MissionRepository,
+    private val userLevelRepository: UserLevelRepository,
 ) : UserMissionRegister {
+    override fun ensureInitialized(userId: UUID) {
+        if (userLevelRepository.existsByUserId(userId)) {
+            return
+        }
+        userLevelRepository.save(UserLevel.create(userId))
+
+        val lv1Mission = missionRepository.findByLevel(1) ?: return
+        val userMission = UserMission.create(userId, lv1Mission.id)
+        userMission.levelUpPopupShown = true
+        userMissionRepository.save(userMission)
+    }
+
     override fun confirmLevelUp(userId: UUID) {
         val userMission =
             userMissionRepository.findCurrentMissionByUserId(userId)

src/main/kotlin/com/didit/application/achievement/provided/UserMissionRegister.kt

@@ -3,6 +3,8 @@ package com.didit.application.achievement.provided
 import java.util.UUID
 
 interface UserMissionRegister {
+    fun ensureInitialized(userId: UUID)
+
     fun confirmLevelUp(userId: UUID)
 
     fun retryMission(userId: UUID)

src/test/kotlin/com/didit/application/achievement/UserMissionServiceTest.kt

@@ -2,6 +2,7 @@ package com.didit.application.achievement
 
 import com.didit.application.achievement.exception.CurrentMissionNotFoundException
 import com.didit.application.achievement.required.MissionRepository
+import com.didit.application.achievement.required.UserLevelRepository
 import com.didit.application.achievement.required.UserMissionRepository
 import com.didit.domain.achievement.Mission
 import com.didit.domain.achievement.MissionStatus
@@ -15,6 +16,7 @@ import org.junit.jupiter.api.extension.ExtendWith
 import org.mockito.Mock
 import org.mockito.junit.jupiter.MockitoExtension
 import org.mockito.kotlin.any
+import org.mockito.kotlin.never
 import org.mockito.kotlin.verify
 import org.mockito.kotlin.whenever
 import java.time.LocalDateTime
@@ -28,14 +30,38 @@ class UserMissionServiceTest {
     @Mock
     lateinit var missionRepository: MissionRepository
 
+    @Mock
+    lateinit var userLevelRepository: UserLevelRepository
+
     private lateinit var userMissionService: UserMissionService
 
     private val userId = UUID.randomUUID()
     private val missionId = UUID.randomUUID()
 
     @BeforeEach
     fun setUp() {
-        userMissionService = UserMissionService(userMissionRepository, missionRepository)
+        userMissionService = UserMissionService(userMissionRepository, missionRepository, userLevelRepository)
+    }
+
+    @Test
+    fun `레벨 정보가 없으면 UserLevel과 Lv1 미션을 생성한다`() {
+        whenever(userLevelRepository.existsByUserId(userId)).thenReturn(false)
+        whenever(missionRepository.findByLevel(1)).thenReturn(Mission.firstRetro())
+
+        userMissionService.ensureInitialized(userId)
+
+        verify(userLevelRepository).save(any())
+        verify(userMissionRepository).save(any())
+    }
+
+    @Test
+    fun `이미 레벨 정보가 있으면 아무것도 생성하지 않는다`() {
+        whenever(userLevelRepository.existsByUserId(userId)).thenReturn(true)
+
+        userMissionService.ensureInitialized(userId)
+
+        verify(userLevelRepository, never()).save(any())
+        verify(userMissionRepository, never()).save(any())
     }
 
     @Test