refactor(chat): 채팅방 시간 표시 책임을 분리한다

app/src/test/java/kr/co/vividnext/sodalive/v2/main/chat/ChatRoomMapperTest.kt

@@ -1,11 +1,8 @@
 package kr.co.vividnext.sodalive.v2.main.chat
 
 import android.app.Application
-import android.content.Context
-import androidx.test.core.app.ApplicationProvider
 import kr.co.vividnext.sodalive.v2.main.chat.data.ChatRoomListItemResponse
 import kr.co.vividnext.sodalive.v2.main.chat.model.ChatRoomType
-import kr.co.vividnext.sodalive.v2.main.chat.model.formatChatRoomLastMessageTime
 import kr.co.vividnext.sodalive.v2.main.chat.model.toUiItem
 import kr.co.vividnext.sodalive.v2.main.chat.model.toUiItems
 import org.junit.Assert.assertEquals
@@ -21,11 +18,9 @@ import org.robolectric.annotation.Config
 @Config(sdk = [28], application = Application::class)
 class ChatRoomMapperTest {
 
-    private val context: Context = ApplicationProvider.getApplicationContext()
-
     @Test
     fun `AI 채팅방은 Direct badge 미표시 item으로 매핑된다`() {
-        val item = response(chatType = "AI").toUiItem(context)
+        val item = response(chatType = "AI").toUiItem()
 
         requireNotNull(item)
         assertEquals(ChatRoomType.AI, item.chatType)
@@ -34,7 +29,7 @@ class ChatRoomMapperTest {
 
     @Test
     fun `DM 채팅방은 Direct badge 표시 item으로 매핑된다`() {
-        val item = response(chatType = "DM").toUiItem(context)
+        val item = response(chatType = "DM").toUiItem()
 
         requireNotNull(item)
         assertEquals(ChatRoomType.DM, item.chatType)
@@ -42,27 +37,27 @@ class ChatRoomMapperTest {
     }
 
     @Test
-    fun `응답 필드는 그대로 전달하고 시간은 표시 문구로 매핑한다`() {
+    fun `응답 필드는 그대로 전달하고 시간은 원본 문자열로 매핑한다`() {
         val item = response(
             roomId = 20L,
             targetName = "상대방",
             targetImageUrl = "https://example.com/profile.png",
             lastMessage = "마지막 메시지",
             lastMessageAt = "2026-06-09T11:57:00Z"
-        ).toUiItem(context)
+        ).toUiItem()
 
         requireNotNull(item)
         assertEquals(20L, item.roomId)
         assertEquals("상대방", item.targetName)
         assertEquals("https://example.com/profile.png", item.targetImageUrl)
         assertEquals("마지막 메시지", item.lastMessage)
-        assertEquals(formatChatRoomLastMessageTime(context, "2026-06-09T11:57:00Z"), item.lastMessageTimeText)
+        assertEquals("2026-06-09T11:57:00Z", item.lastMessageAt)
     }
 
     @Test
     fun `알 수 없는 chatType은 표시 대상에서 제외한다`() {
-        assertNull(response(chatType = "GROUP").toUiItem(context))
-        assertEquals(emptyList<Any>(), listOf(response(chatType = "GROUP")).toUiItems(context))
+        assertNull(response(chatType = "GROUP").toUiItem())
+        assertEquals(emptyList<Any>(), listOf(response(chatType = "GROUP")).toUiItems())
     }
 
     private fun response(