Replace GetUserNewsResourcesUseCase with UserNewsResourceRepository

This moves the responsibility for joining the UserData and the
NewsResources to UserNewsResourceRepository. This way, the work can be
done once and shared with all consumers in a SharedFlow, rather than
having each consumer perform the join itself by invoking the UseCase.

core/common/src/main/java/com/google/samples/apps/nowinandroid/core/network/NiaDispatchers.kt

@@ -24,5 +24,6 @@ import kotlin.annotation.AnnotationRetention.RUNTIME
 annotation class Dispatcher(val niaDispatcher: NiaDispatchers)
 
 enum class NiaDispatchers {
+    Default,
     IO,
 }

core/common/src/main/java/com/google/samples/apps/nowinandroid/core/network/di/DispatchersModule.kt

@@ -17,6 +17,7 @@
 package com.google.samples.apps.nowinandroid.core.network.di
 
 import com.google.samples.apps.nowinandroid.core.network.Dispatcher
+import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.Default
 import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.IO
 import dagger.Module
 import dagger.Provides
@@ -31,4 +32,8 @@ object DispatchersModule {
     @Provides
     @Dispatcher(IO)
     fun providesIODispatcher(): CoroutineDispatcher = Dispatchers.IO
+
+    @Provides
+    @Dispatcher(Default)
+    fun providesDefaultDispatcher(): CoroutineDispatcher = Dispatchers.Default
 }

core/domain/src/main/java/com/google/samples/apps/nowinandroid/core/domain/GetUserNewsResourcesUseCase.kt

@@ -1,58 +0,0 @@
-/*
- * Copyright 2022 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.samples.apps.nowinandroid.core.domain
-
-import com.google.samples.apps.nowinandroid.core.data.repository.NewsRepository
-import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQuery
-import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
-import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
-import com.google.samples.apps.nowinandroid.core.domain.model.mapToUserNewsResources
-import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
-import com.google.samples.apps.nowinandroid.core.model.data.UserData
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.filterNot
-import javax.inject.Inject
-
-/**
- * A use case responsible for obtaining news resources with their associated bookmarked (also known
- * as "saved") state.
- */
-class GetUserNewsResourcesUseCase @Inject constructor(
-    private val newsRepository: NewsRepository,
-    private val userDataRepository: UserDataRepository,
-) {
-    /**
-     * Returns a list of UserNewsResources which match the supplied set of topic ids.
-     *
-     * @param query - Summary of query parameters for news resources.
-     */
-    operator fun invoke(
-        query: NewsResourceQuery = NewsResourceQuery(),
-    ): Flow<List<UserNewsResource>> =
-        newsRepository.getNewsResources(
-            query = query,
-        ).mapToUserNewsResources(userDataRepository.userData)
-}
-
-private fun Flow<List<NewsResource>>.mapToUserNewsResources(
-    userDataStream: Flow<UserData>,
-): Flow<List<UserNewsResource>> =
-    filterNot { it.isEmpty() }
-        .combine(userDataStream) { newsResources, userData ->
-            newsResources.mapToUserNewsResources(userData)
-        }

core/domain/src/main/java/com/google/samples/apps/nowinandroid/core/domain/di/CoroutineScopesModule.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.domain.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import javax.inject.Qualifier
+import javax.inject.Singleton
+
+@Retention(AnnotationRetention.RUNTIME)
+@Qualifier
+annotation class ApplicationScope
+
+@InstallIn(SingletonComponent::class)
+@Module
+object CoroutinesScopesModule {
+
+    @Singleton
+    @ApplicationScope
+    @Provides
+    fun providesCoroutineScope(): CoroutineScope =
+        CoroutineScope(SupervisorJob() + Dispatchers.Default)
+}

core/domain/src/main/java/com/google/samples/apps/nowinandroid/core/domain/di/UserNewsResourceRepositoryModule.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.domain.di
+
+import com.google.samples.apps.nowinandroid.core.domain.repository.CompositeUserNewsResourceRepository
+import com.google.samples.apps.nowinandroid.core.domain.repository.UserNewsResourceRepository
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+
+@Module
+@InstallIn(SingletonComponent::class)
+interface UserNewsResourceRepositoryModule {
+    @Binds
+    fun bindsUserNewsResourceRepository(
+        userDataRepository: CompositeUserNewsResourceRepository,
+    ): UserNewsResourceRepository
+}

core/domain/src/main/java/com/google/samples/apps/nowinandroid/core/domain/repository/CompositeUserNewsResourceRepository.kt

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.domain.repository
+
+import com.google.samples.apps.nowinandroid.core.data.repository.NewsRepository
+import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQuery
+import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
+import com.google.samples.apps.nowinandroid.core.domain.di.ApplicationScope
+import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
+import com.google.samples.apps.nowinandroid.core.domain.model.mapToUserNewsResources
+import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
+import com.google.samples.apps.nowinandroid.core.model.data.UserData
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.SharingStarted.Companion.WhileSubscribed
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.filterNot
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.shareIn
+import javax.inject.Inject
+
+/**
+ * Implements a [UserNewsResourceRepository] by combining a [NewsRepository] with a
+ * [UserDataRepository].
+ */
+class CompositeUserNewsResourceRepository @Inject constructor(
+    @ApplicationScope private val coroutineScope: CoroutineScope,
+    val newsRepository: NewsRepository,
+    val userDataRepository: UserDataRepository,
+) : UserNewsResourceRepository {
+
+    private val userNewsResources =
+        newsRepository.getNewsResources().mapToUserNewsResources(userDataRepository.userData)
+            .shareIn(coroutineScope, started = WhileSubscribed(5000), replay = 1)
+
+    override fun getUserNewsResources(
+        query: NewsResourceQuery,
+    ): Flow<List<UserNewsResource>> =
+        userNewsResources.map { resources ->
+            resources.filter { resource ->
+                query.filterTopicIds?.let { topics -> resource.hasTopic(topics) } ?: true &&
+                    query.filterNewsIds?.contains(resource.id) ?: true
+            }
+        }
+
+    override fun getUserNewsResourcesForFollowedTopics(): Flow<List<UserNewsResource>> =
+        userDataRepository.userData.flatMapLatest { getUserNewsResources(NewsResourceQuery(filterTopicIds = it.followedTopics)) }
+
+    private fun UserNewsResource.hasTopic(filterTopicIds: Set<String>) =
+        followableTopics.any { filterTopicIds.contains(it.topic.id) }
+}
+
+private fun Flow<List<NewsResource>>.mapToUserNewsResources(
+    userDataStream: Flow<UserData>,
+): Flow<List<UserNewsResource>> =
+    filterNot { it.isEmpty() }
+        .combine(userDataStream) { newsResources, userData ->
+            newsResources.mapToUserNewsResources(userData)
+        }

core/domain/src/main/java/com/google/samples/apps/nowinandroid/core/domain/repository/UserNewsResourceRepository.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.domain.repository
+
+import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQuery
+import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Data layer implementation for [UserNewsResource]
+ */
+interface UserNewsResourceRepository {
+    /**
+     * Returns available news resources as a stream.
+     */
+    fun getUserNewsResources(
+        query: NewsResourceQuery = NewsResourceQuery(
+            filterTopicIds = null,
+            filterNewsIds = null,
+        ),
+    ): Flow<List<UserNewsResource>>
+
+    /**
+     * Returns available news resources for the user's followed topics as a stream.
+     */
+    fun getUserNewsResourcesForFollowedTopics(): Flow<List<UserNewsResource>>
+}

core/domain/src/test/java/com/google/samples/apps/nowinandroid/core/domain/CompositeUserNewsResourceRepositoryTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Android Open Source Project
+ * Copyright 2023 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,34 +18,36 @@ package com.google.samples.apps.nowinandroid.core.domain
 
 import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQuery
 import com.google.samples.apps.nowinandroid.core.domain.model.mapToUserNewsResources
+import com.google.samples.apps.nowinandroid.core.domain.repository.CompositeUserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResourceType.Video
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestNewsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestUserDataRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.emptyUserData
-import com.google.samples.apps.nowinandroid.core.testing.util.MainDispatcherRule
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import kotlinx.datetime.Instant
-import org.junit.Rule
 import org.junit.Test
 import kotlin.test.assertEquals
 
-class GetUserNewsResourcesUseCaseTest {
+class CompositeUserNewsResourceRepositoryTest {
-
-    @get:Rule
-    val mainDispatcherRule = MainDispatcherRule()
 
     private val newsRepository = TestNewsRepository()
     private val userDataRepository = TestUserDataRepository()
 
-    val useCase = GetUserNewsResourcesUseCase(newsRepository, userDataRepository)
+    private val userNewsResourceRepository = CompositeUserNewsResourceRepository(
+        coroutineScope = TestScope(UnconfinedTestDispatcher()),
+        newsRepository = newsRepository,
+        userDataRepository = userDataRepository,
+    )
 
     @Test
     fun whenNoFilters_allNewsResourcesAreReturned() = runTest {
-        // Obtain the user news resources stream.
+        // Obtain the user news resources flow.
-        val userNewsResources = useCase()
+        val userNewsResources = userNewsResourceRepository.getUserNewsResources()
 
         // Send some news resources and user data into the data repositories.
         newsRepository.sendNewsResources(sampleNewsResources)
@@ -68,11 +70,8 @@ class GetUserNewsResourcesUseCaseTest {
     @Test
     fun whenFilteredByTopicId_matchingNewsResourcesAreReturned() = runTest {
         // Obtain a stream of user news resources for the given topic id.
-        val userNewsResources = useCase(
+        val userNewsResources =
-            NewsResourceQuery(
+            userNewsResourceRepository.getUserNewsResources(NewsResourceQuery(filterTopicIds = setOf(sampleTopic1.id)))
-                filterTopicIds = setOf(sampleTopic1.id),
-            ),
-        )
 
         // Send test data into the repositories.
         newsRepository.sendNewsResources(sampleNewsResources)
@@ -86,6 +85,28 @@ class GetUserNewsResourcesUseCaseTest {
             userNewsResources.first(),
         )
     }
+
+    @Test
+    fun whenFilteredByFollowedTopics_matchingNewsResourcesAreReturned() = runTest {
+        // Obtain a stream of user news resources for the given topic id.
+        val userNewsResources =
+            userNewsResourceRepository.getUserNewsResourcesForFollowedTopics()
+
+        // Send test data into the repositories.
+        val userData = emptyUserData.copy(
+            followedTopics = setOf(sampleTopic1.id),
+        )
+        newsRepository.sendNewsResources(sampleNewsResources)
+        userDataRepository.setUserData(userData)
+
+        // Check that only news resources with the given topic id are returned.
+        assertEquals(
+            sampleNewsResources
+                .filter { it.topics.contains(sampleTopic1) }
+                .mapToUserNewsResources(userData),
+            userNewsResources.first(),
+        )
+    }
 }
 
 private val sampleTopic1 = Topic(

feature/bookmarks/src/main/java/com/google/samples/apps/nowinandroid/feature/bookmarks/BookmarksViewModel.kt

@@ -19,8 +19,8 @@ package com.google.samples.apps.nowinandroid.feature.bookmarks
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
-import com.google.samples.apps.nowinandroid.core.domain.GetUserNewsResourcesUseCase
 import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
+import com.google.samples.apps.nowinandroid.core.domain.repository.UserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.ui.NewsFeedUiState
 import com.google.samples.apps.nowinandroid.core.ui.NewsFeedUiState.Loading
 import dagger.hilt.android.lifecycle.HiltViewModel
@@ -36,10 +36,10 @@ import javax.inject.Inject
 @HiltViewModel
 class BookmarksViewModel @Inject constructor(
     private val userDataRepository: UserDataRepository,
-    getSaveableNewsResources: GetUserNewsResourcesUseCase,
+    userNewsResourceRepository: UserNewsResourceRepository,
 ) : ViewModel() {
 
-    val feedUiState: StateFlow<NewsFeedUiState> = getSaveableNewsResources()
+    val feedUiState: StateFlow<NewsFeedUiState> = userNewsResourceRepository.getUserNewsResources()
         .filterNot { it.isEmpty() }
         .map { newsResources -> newsResources.filter(UserNewsResource::isSaved) } // Only show bookmarked news resources.
         .map<List<UserNewsResource>, NewsFeedUiState>(NewsFeedUiState::Success)

feature/bookmarks/src/test/java/com/google/samples/apps/nowinandroid/feature/bookmarks/BookmarksViewModelTest.kt

@@ -16,7 +16,7 @@
 
 package com.google.samples.apps.nowinandroid.feature.bookmarks
 
-import com.google.samples.apps.nowinandroid.core.domain.GetUserNewsResourcesUseCase
+import com.google.samples.apps.nowinandroid.core.domain.repository.CompositeUserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.testing.data.newsResourcesTestData
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestNewsRepository
 import com.google.samples.apps.nowinandroid.core.testing.repository.TestUserDataRepository
@@ -25,6 +25,7 @@ import com.google.samples.apps.nowinandroid.core.ui.NewsFeedUiState.Loading
 import com.google.samples.apps.nowinandroid.core.ui.NewsFeedUiState.Success
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
@@ -43,7 +44,8 @@ class BookmarksViewModelTest {
 
     private val userDataRepository = TestUserDataRepository()
     private val newsRepository = TestNewsRepository()
-    private val getUserNewsResourcesUseCase = GetUserNewsResourcesUseCase(
+    private val userNewsResourceRepository = CompositeUserNewsResourceRepository(
+        coroutineScope = TestScope(UnconfinedTestDispatcher()),
         newsRepository = newsRepository,
         userDataRepository = userDataRepository,
     )
@@ -53,7 +55,7 @@ class BookmarksViewModelTest {
     fun setup() {
         viewModel = BookmarksViewModel(
             userDataRepository = userDataRepository,
-            getSaveableNewsResources = getUserNewsResourcesUseCase,
+            userNewsResourceRepository = userNewsResourceRepository,
         )
     }
 

feature/foryou/src/main/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModel.kt

@@ -22,8 +22,8 @@ import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQue
 import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
 import com.google.samples.apps.nowinandroid.core.data.util.SyncStatusMonitor
 import com.google.samples.apps.nowinandroid.core.domain.GetFollowableTopicsUseCase
-import com.google.samples.apps.nowinandroid.core.domain.GetUserNewsResourcesUseCase
 import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
+import com.google.samples.apps.nowinandroid.core.domain.repository.UserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.model.data.UserData
 import com.google.samples.apps.nowinandroid.core.ui.NewsFeedUiState
 import dagger.hilt.android.lifecycle.HiltViewModel
@@ -43,7 +43,7 @@ import javax.inject.Inject
 class ForYouViewModel @Inject constructor(
     syncStatusMonitor: SyncStatusMonitor,
     private val userDataRepository: UserDataRepository,
-    getUserNewsResources: GetUserNewsResourcesUseCase,
+    userNewsResourceRepository: UserNewsResourceRepository,
     getFollowableTopics: GetFollowableTopicsUseCase,
 ) : ViewModel() {
 
@@ -58,7 +58,7 @@ class ForYouViewModel @Inject constructor(
         )
 
     val feedState: StateFlow<NewsFeedUiState> =
-        userDataRepository.getFollowedUserNewsResources(getUserNewsResources)
+        userDataRepository.getFollowedUserNewsResources(userNewsResourceRepository)
             .map(NewsFeedUiState::Success)
             .stateIn(
                 scope = viewModelScope,
@@ -108,7 +108,7 @@ class ForYouViewModel @Inject constructor(
  * getUserNewsResources: The `UseCase` used to obtain the flow of user news resources.
  */
 private fun UserDataRepository.getFollowedUserNewsResources(
-    getUserNewsResources: GetUserNewsResourcesUseCase,
+    userNewsResourceRepository: UserNewsResourceRepository,
 ): Flow<List<UserNewsResource>> = userData
     // Map the user data into a set of followed topic IDs or null if we should return an empty list.
     .map { userData ->
@@ -128,10 +128,8 @@ private fun UserDataRepository.getFollowedUserNewsResources(
         if (followedTopics == null) {
             flowOf(emptyList())
         } else {
-            getUserNewsResources(
+            userNewsResourceRepository.getUserNewsResources(
-                NewsResourceQuery(
+                NewsResourceQuery(filterTopicIds = followedTopics),
-                    filterTopicIds = followedTopics,
-                ),
             )
         }
     }

feature/foryou/src/test/java/com/google/samples/apps/nowinandroid/feature/foryou/ForYouViewModelTest.kt

@@ -17,10 +17,10 @@
 package com.google.samples.apps.nowinandroid.feature.foryou
 
 import com.google.samples.apps.nowinandroid.core.domain.GetFollowableTopicsUseCase
-import com.google.samples.apps.nowinandroid.core.domain.GetUserNewsResourcesUseCase
 import com.google.samples.apps.nowinandroid.core.domain.model.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
 import com.google.samples.apps.nowinandroid.core.domain.model.mapToUserNewsResources
+import com.google.samples.apps.nowinandroid.core.domain.repository.CompositeUserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResourceType.Video
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
@@ -34,6 +34,7 @@ import com.google.samples.apps.nowinandroid.core.testing.util.TestSyncStatusMoni
 import com.google.samples.apps.nowinandroid.core.ui.NewsFeedUiState
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.advanceUntilIdle
 import kotlinx.coroutines.test.runTest
@@ -56,7 +57,8 @@ class ForYouViewModelTest {
     private val userDataRepository = TestUserDataRepository()
     private val topicsRepository = TestTopicsRepository()
     private val newsRepository = TestNewsRepository()
-    private val getUserNewsResourcesUseCase = GetUserNewsResourcesUseCase(
+    private val userNewsResourceRepository = CompositeUserNewsResourceRepository(
+        coroutineScope = TestScope(UnconfinedTestDispatcher()),
         newsRepository = newsRepository,
         userDataRepository = userDataRepository,
     )
@@ -72,7 +74,7 @@ class ForYouViewModelTest {
         viewModel = ForYouViewModel(
             syncStatusMonitor = syncStatusMonitor,
             userDataRepository = userDataRepository,
-            getUserNewsResources = getUserNewsResourcesUseCase,
+            userNewsResourceRepository = userNewsResourceRepository,
             getFollowableTopics = getFollowableTopicsUseCase,
         )
     }

feature/topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt

@@ -23,9 +23,9 @@ import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQue
 import com.google.samples.apps.nowinandroid.core.data.repository.TopicsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
 import com.google.samples.apps.nowinandroid.core.decoder.StringDecoder
-import com.google.samples.apps.nowinandroid.core.domain.GetUserNewsResourcesUseCase
 import com.google.samples.apps.nowinandroid.core.domain.model.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.domain.model.UserNewsResource
+import com.google.samples.apps.nowinandroid.core.domain.repository.UserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.result.Result
 import com.google.samples.apps.nowinandroid.core.result.asResult
@@ -46,7 +46,7 @@ class TopicViewModel @Inject constructor(
     stringDecoder: StringDecoder,
     private val userDataRepository: UserDataRepository,
     topicsRepository: TopicsRepository,
-    getSaveableNewsResources: GetUserNewsResourcesUseCase,
+    userNewsResourceRepository: UserNewsResourceRepository,
 ) : ViewModel() {
 
     private val topicArgs: TopicArgs = TopicArgs(savedStateHandle, stringDecoder)
@@ -67,7 +67,7 @@ class TopicViewModel @Inject constructor(
     val newUiState: StateFlow<NewsUiState> = newsUiState(
         topicId = topicArgs.topicId,
         userDataRepository = userDataRepository,
-        getSaveableNewsResources = getSaveableNewsResources,
+        userNewsResourceRepository = userNewsResourceRepository,
     )
         .stateIn(
             scope = viewModelScope,
@@ -135,14 +135,12 @@ private fun topicUiState(
 
 private fun newsUiState(
     topicId: String,
-    getSaveableNewsResources: GetUserNewsResourcesUseCase,
+    userNewsResourceRepository: UserNewsResourceRepository,
     userDataRepository: UserDataRepository,
 ): Flow<NewsUiState> {
     // Observe news
-    val newsStream: Flow<List<UserNewsResource>> = getSaveableNewsResources(
+    val newsStream: Flow<List<UserNewsResource>> = userNewsResourceRepository.getUserNewsResources(
-        NewsResourceQuery(
+        NewsResourceQuery(filterTopicIds = setOf(element = topicId)),
-            filterTopicIds = setOf(element = topicId),
-        ),
     )
 
     // Observe bookmarks

feature/topic/src/test/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModelTest.kt

@@ -17,8 +17,8 @@
 package com.google.samples.apps.nowinandroid.feature.topic
 
 import androidx.lifecycle.SavedStateHandle
-import com.google.samples.apps.nowinandroid.core.domain.GetUserNewsResourcesUseCase
 import com.google.samples.apps.nowinandroid.core.domain.model.FollowableTopic
+import com.google.samples.apps.nowinandroid.core.domain.repository.CompositeUserNewsResourceRepository
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResourceType.Video
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
@@ -32,6 +32,7 @@ import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import kotlinx.datetime.Instant
@@ -53,7 +54,8 @@ class TopicViewModelTest {
     private val userDataRepository = TestUserDataRepository()
     private val topicsRepository = TestTopicsRepository()
     private val newsRepository = TestNewsRepository()
-    private val getUserNewsResourcesUseCase = GetUserNewsResourcesUseCase(
+    private val userNewsResourceRepository = CompositeUserNewsResourceRepository(
+        coroutineScope = TestScope(UnconfinedTestDispatcher()),
         newsRepository = newsRepository,
         userDataRepository = userDataRepository,
     )
@@ -66,7 +68,7 @@ class TopicViewModelTest {
             stringDecoder = FakeStringDecoder(),
             userDataRepository = userDataRepository,
             topicsRepository = topicsRepository,
-            getSaveableNewsResources = getUserNewsResourcesUseCase,
+            userNewsResourceRepository = userNewsResourceRepository,
         )
     }