ASAP-451 편지 조회 로직 수정 및 테스트 보완

- `send_letter.sender_id` nullable 처리에 따른 조회 로직 수정: 관련 도메인 및 데이터 클래스를 업데이트.
- `senderName` 필드를 null 허용하도록 변경.
- 테스트 코드에서 null 처리 로직 보완.

Author: tlarbals824

Application-Module/src/main/kotlin/com/asap/application/letter/port/in/GetVerifiedLetterUsecase.kt

@@ -3,23 +3,18 @@ package com.asap.application.letter.port.`in`
 import java.time.LocalDate
 
 interface GetVerifiedLetterUsecase {
-
-    fun get(
-        query: Query
-    ): Response
+    fun get(query: Query): Response
 
     data class Query(
         val letterId: String,
-        val userId: String
+        val userId: String,
     )
 
     data class Response(
-        val senderName: String,
+        val senderName: String?,
         val content: String,
         val sendDate: LocalDate,
         val templateType: Int,
-        val images: List<String>
+        val images: List<String>,
     )
-
-
-}
+}

Application-Module/src/main/kotlin/com/asap/application/letter/service/LetterQueryService.kt

@@ -32,9 +32,9 @@ class LetterQueryService(
                 receiverId = DomainId(query.userId),
                 letterId = DomainId(query.letterId),
             ).also {
-                val sender = userManagementPort.getUserNotNull(it.senderId)
+                val sender = it.senderId?.let { userManagementPort.getUserNotNull(it) }
                 return GetVerifiedLetterUsecase.Response(
-                    senderName = sender.username,
+                    senderName = sender?.username,
                     content = it.content.content,
                     sendDate = it.createdDate,
                     templateType = it.content.templateType,

Application-Module/src/test/kotlin/com/asap/application/letter/service/LetterQueryServiceTest.kt

@@ -42,7 +42,7 @@ class LetterQueryServiceTest :
                     userId = user.id.value,
                 )
             val mockSendLetter = LetterFixture.generateSendLetter(user.id)
-            val mockSender = UserFixture.createUser(mockSendLetter.senderId, "sender-name")
+            val mockSender = UserFixture.createUser(mockSendLetter.senderId!!, "sender-name")
             every {
                 mockSendLetterManagementPort.getReadLetterNotNull(
                     receiverId = DomainId(query.userId),
@@ -96,9 +96,10 @@ class LetterQueryServiceTest :
                     letterId = "letter-id",
                     userId = "user-id",
                 )
-            val space = SpaceFixture.createSpace(
-                userId = DomainId(query.userId),
-            )
+            val space =
+                SpaceFixture.createSpace(
+                    userId = DomainId(query.userId),
+                )
             val spaceLetter = LetterFixture.generateSpaceLetter(receiverId = DomainId(query.userId), spaceId = space.id)
             val prevSpaceLetter =
                 LetterFixture.generateSpaceLetter(receiverId = DomainId(query.userId), spaceId = space.id)

Bootstrap-Module/src/main/kotlin/com/asap/bootstrap/web/letter/dto/VerifiedLetterInfoResponse.kt

@@ -3,10 +3,9 @@ package com.asap.bootstrap.web.letter.dto
 import java.time.LocalDate
 
 data class VerifiedLetterInfoResponse(
-    val senderName: String,
+    val senderName: String?,
     val content: String,
     val date: LocalDate,
     val templateType: Int,
-    val images: List<String>
-) {
-}
+    val images: List<String>,
+)

Bootstrap-Module/src/main/kotlin/com/asap/bootstrap/web/letter/handler/DraftLetterEventHandler.kt

@@ -16,7 +16,7 @@ class DraftLetterEventHandler(
         event.draftId?.let {
             removeDraftLetterUsecase.deleteBy(
                 RemoveDraftLetterUsecase.Command.Send(
-                    userId = event.sendLetter.senderId.value,
+                    userId = event.sendLetter.senderId!!.value,
                     draftId = it,
                 ),
             )