닉네임 중복 확인 지연 단축

TEST_STRATEGY.md

@@ -150,6 +150,11 @@ verification domain의 아래 테스트로 대체하고 생성·참여 연동 
 - `ChallengeTargetsViewModelTest`: 데이터 없음·조회 실패도 초기 로딩을 종료하는지 검사한다.
 - `assembleDebug`, `test`, `lint` 통과. 서버 인수 테스트는 기본 실행에서 제외되며, OS 권한창·FCM·실제 지도·Health Connect·릴리즈 설치는 이번에 실행하지 않았다.
 
+### 온보딩 닉네임 중복 확인 (#643)
+
+- ViewModel 테스트에서 입력 후 250ms 대기, 이전 요청 취소, 잘못된 값을 거쳐 같은 닉네임을 다시 입력하는 경로와 서버 확인 실패 후 재시도를 검증한다.
+- 서버 응답 속도에 따른 체감 지연은 실제 서버와 기기에서 확인해야 한다.
+
 ## 4. 인수 시나리오 ↔ 하위 테스트
 
 인수가 깨졌는데 하위 층이 전부 초록이었다면 **하위 층에 구멍이 있다**는 뜻이고, 그게 다음 작업이다.

onboarding/presentation/src/main/kotlin/com/ruleup/onboarding/presentation/onboarding/viewmodel/OnboardingViewModel.kt

@@ -26,10 +26,12 @@ import com.ruleup.profile.domain.entity.NicknameCheckReason
 import com.ruleup.profile.domain.repository.ProfileRepository
 import com.ruleup.ui.mvi.MviViewModel
 import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.channels.BufferOverflow
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.debounce
-import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
@@ -50,14 +52,16 @@ class OnboardingViewModel
         private val pendingDeepLink: PendingDeepLink,
     ) : MviViewModel<OnboardingIntent, OnboardingState, OnboardingReducerEvent, OnboardingEffect>(OnboardingState.initial) {
         /** 닉네임 입력 스트림. */
-        private val nicknameInput = MutableSharedFlow<String>(extraBufferCapacity = 1)
+        private val nicknameInput =
+            MutableSharedFlow<String>(replay = 1, extraBufferCapacity = 1, onBufferOverflow = BufferOverflow.DROP_OLDEST)
 
         init {
             viewModelScope.launch {
                 nicknameInput
                     .debounce(NICKNAME_DEBOUNCE_MS)
-                    .distinctUntilChanged()
-                    .collect { checkNickname(it) }
+                    .collectLatest { name ->
+                        if (NickNameUtil.validate(name).isValid) checkNickname(name)
+                    }
             }
             // IdP 닉네임을 채워 준다.
             signupSession
@@ -141,6 +145,7 @@ class OnboardingViewModel
 
         private fun enterNickname(name: String) {
             dispatch(OnboardingReducerEvent.NicknameEntered(name))
+            nicknameInput.tryEmit(name)
             // 형식이 틀린 건 서버에 묻지 않고 바로 알려 준다.
             val validation = NickNameUtil.validate(name)
             if (!validation.isValid) {
@@ -152,7 +157,6 @@ class OnboardingViewModel
                 )
                 return
             }
-            nicknameInput.tryEmit(name)
         }
 
         private suspend fun checkNickname(name: String) {
@@ -174,6 +178,7 @@ class OnboardingViewModel
                         ),
                     )
                 }.onFailure {
+                    if (it is CancellationException) throw it
                     if (currentState.nickname != name) return@onFailure
                     // 확인 실패는 "쓸 수 없음"이 아니다.
                     dispatch(
@@ -296,7 +301,7 @@ class OnboardingViewModel
         }
 
         private companion object {
-            const val NICKNAME_DEBOUNCE_MS = 500L
+            const val NICKNAME_DEBOUNCE_MS = 250L
         }
     }
 

onboarding/presentation/src/test/kotlin/com/ruleup/onboarding/presentation/onboarding/viewmodel/OnboardingViewModelTest.kt

@@ -16,13 +16,18 @@ import com.ruleup.onboarding.domain.fake.FakeIntroRepository
 import com.ruleup.onboarding.domain.fake.FakeProfileRepository
 import com.ruleup.onboarding.domain.logging.SignupTimer
 import com.ruleup.onboarding.presentation.common.AuthFailureUi
+import com.ruleup.profile.domain.entity.NicknameCheck
+import com.ruleup.profile.domain.repository.ProfileRepository
+import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.advanceTimeBy
 import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runCurrent
 import kotlinx.coroutines.test.runTest
 import kotlinx.coroutines.test.setMain
 import java.time.Clock
@@ -59,6 +64,114 @@ class OnboardingViewModelTest {
             )
         }
 
+    @Test
+    fun `유효한 닉네임 입력이 멈춘 지 250ms 뒤 서버 확인을 시작한다`() =
+        runTest {
+            val checked = mutableListOf<String>()
+            val profiles =
+                profileRepository {
+                    checked += it
+                    availableNickname()
+                }
+            val viewModel = viewModel(session = SignupSession(), profiles = profiles)
+
+            viewModel.onIntent(OnboardingIntent.SetNickName("도전왕"))
+            advanceTimeBy(249)
+            runCurrent()
+            assertTrue(checked.isEmpty())
+            advanceTimeBy(1)
+            runCurrent()
+
+            assertEquals(listOf("도전왕"), checked)
+            assertEquals(true, viewModel.uiState.value.nicknameAvailable)
+        }
+
+    @Test
+    fun `확인한 닉네임을 지웠다가 다시 입력하면 다시 사용할 수 있다`() =
+        runTest {
+            val checked = mutableListOf<String>()
+            val viewModel =
+                viewModel(
+                    session = SignupSession(),
+                    profiles =
+                        profileRepository {
+                            checked += it
+                            availableNickname()
+                        },
+                )
+            viewModel.onIntent(OnboardingIntent.SetNickName("도전왕"))
+            advanceTimeBy(600)
+            runCurrent()
+            viewModel.onIntent(OnboardingIntent.SetNickName(""))
+            viewModel.onIntent(OnboardingIntent.SetNickName("도전왕"))
+            advanceTimeBy(600)
+            runCurrent()
+
+            assertEquals(listOf("도전왕", "도전왕"), checked)
+            assertEquals(true, viewModel.uiState.value.nicknameAvailable)
+        }
+
+    @Test
+    fun `닉네임 확인이 실패해도 다시 입력하면 서버 확인 후 진행할 수 있다`() =
+        runTest {
+            var attempts = 0
+            val viewModel =
+                viewModel(
+                    session = SignupSession(),
+                    profiles =
+                        profileRepository {
+                            attempts++
+                            if (attempts == 1) throw java.io.IOException("offline")
+                            availableNickname()
+                        },
+                )
+
+            viewModel.onIntent(OnboardingIntent.SetNickName("도전왕"))
+            advanceTimeBy(250)
+            runCurrent()
+            assertEquals(null, viewModel.uiState.value.nicknameAvailable)
+            assertTrue(
+                viewModel.uiState.value.nicknameMessage
+                    ?.contains("확인하지 못했어요") == true,
+            )
+
+            viewModel.onIntent(OnboardingIntent.SetNickName(""))
+            viewModel.onIntent(OnboardingIntent.SetNickName("도전왕"))
+            advanceTimeBy(250)
+            runCurrent()
+            assertEquals(2, attempts)
+            assertEquals(true, viewModel.uiState.value.nicknameAvailable)
+        }
+
+    @Test
+    fun `이전 닉네임 확인이 오래 걸려도 새 입력을 확인한다`() =
+        runTest {
+            val checked = mutableListOf<String>()
+            val first = CompletableDeferred<NicknameCheck>()
+            val profiles =
+                profileRepository { name ->
+                    checked += name
+                    if (name == "도전왕") first.await() else availableNickname()
+                }
+            val viewModel = viewModel(session = SignupSession(), profiles = profiles)
+            viewModel.onIntent(OnboardingIntent.SetNickName("도전왕"))
+            advanceTimeBy(600)
+            runCurrent()
+            viewModel.onIntent(OnboardingIntent.SetNickName("새로운왕"))
+            advanceTimeBy(600)
+            runCurrent()
+
+            assertEquals(listOf("도전왕", "새로운왕"), checked)
+            assertEquals(true, viewModel.uiState.value.nicknameAvailable)
+        }
+
+    private fun profileRepository(check: suspend (String) -> NicknameCheck): ProfileRepository =
+        object : ProfileRepository by FakeProfileRepository() {
+            override suspend fun checkNickname(nickname: String): NicknameCheck = check(nickname)
+        }
+
+    private fun availableNickname() = NicknameCheck(valid = true, available = true, reason = null)
+
     @Test
     fun `가입 토큰이 만료됐으면 안내를 띄운 뒤 로그인부터 다시 하게 한다`() =
         runTest {
@@ -138,9 +251,9 @@ class OnboardingViewModelTest {
         auth: FakeAuthRepository = FakeAuthRepository(),
         session: SignupSession = startedSession(),
         nav: RecordingNavigationHelper = RecordingNavigationHelper(),
-    ): OnboardingViewModel {
-        val profiles = FakeProfileRepository()
-        return OnboardingViewModel(
+        profiles: ProfileRepository = FakeProfileRepository(),
+    ): OnboardingViewModel =
+        OnboardingViewModel(
             signupUseCase =
                 SignupUseCase(auth, FakeDeviceIdentityRepository(), profiles, FakeTokenRepository(), testObservability()),
             validateBirthDateUseCase =
@@ -153,5 +266,4 @@ class OnboardingViewModelTest {
             navigationHelper = nav,
             pendingDeepLink = PendingDeepLink(),
         )
-    }
 }