Provide a CoroutineScope to fake DataStores

core/data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstNewsRepositoryTest.kt

@@ -36,6 +36,8 @@ import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.network.model.NetworkChangeList
 import com.google.samples.apps.nowinandroid.core.network.model.NetworkNewsResource
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
 import org.junit.Rule
@@ -45,6 +47,8 @@ import kotlin.test.assertEquals
 
 class OfflineFirstNewsRepositoryTest {
 
+    private val testScope = TestScope(UnconfinedTestDispatcher())
+
     private lateinit var subject: OfflineFirstNewsRepository
 
     private lateinit var newsResourceDao: TestNewsResourceDao
@@ -65,7 +69,7 @@ class OfflineFirstNewsRepositoryTest {
         network = TestNiaNetworkDataSource()
         synchronizer = TestSynchronizer(
             NiaPreferencesDataSource(
-                tmpFolder.testUserPreferencesDataStore(),
+                tmpFolder.testUserPreferencesDataStore(testScope),
             ),
         )
 
@@ -78,7 +82,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_news_resources_stream_is_backed_by_news_resource_dao() =
-        runTest {
+        testScope.runTest {
             assertEquals(
                 newsResourceDao.getNewsResources()
                     .first()
@@ -90,7 +94,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_news_resources_for_topic_is_backed_by_news_resource_dao() =
-        runTest {
+        testScope.runTest {
             assertEquals(
                 expected = newsResourceDao.getNewsResources(
                     filterTopicIds = filteredInterestsIds,
@@ -119,7 +123,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_sync_pulls_from_network() =
-        runTest {
+        testScope.runTest {
             subject.syncWith(synchronizer)
 
             val newsResourcesFromNetwork = network.getNewsResources()
@@ -144,7 +148,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_sync_deletes_items_marked_deleted_on_network() =
-        runTest {
+        testScope.runTest {
             val newsResourcesFromNetwork = network.getNewsResources()
                 .map(NetworkNewsResource::asEntity)
                 .map(NewsResourceEntity::asExternalModel)
@@ -185,7 +189,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_incremental_sync_pulls_from_network() =
-        runTest {
+        testScope.runTest {
             // Set news version to 7
             synchronizer.updateChangeListVersions {
                 copy(newsResourceVersion = 7)
@@ -224,7 +228,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_sync_saves_shell_topic_entities() =
-        runTest {
+        testScope.runTest {
             subject.syncWith(synchronizer)
 
             assertEquals(
@@ -239,7 +243,7 @@ class OfflineFirstNewsRepositoryTest {
 
     @Test
     fun offlineFirstNewsRepository_sync_saves_topic_cross_references() =
-        runTest {
+        testScope.runTest {
             subject.syncWith(synchronizer)
 
             assertEquals(

core/data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstTopicsRepositoryTest.kt

@@ -29,6 +29,8 @@ import com.google.samples.apps.nowinandroid.core.datastore.test.testUserPreferen
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.network.model.NetworkTopic
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
 import org.junit.Rule
@@ -38,6 +40,8 @@ import kotlin.test.assertEquals
 
 class OfflineFirstTopicsRepositoryTest {
 
+    private val testScope = TestScope(UnconfinedTestDispatcher())
+
     private lateinit var subject: OfflineFirstTopicsRepository
 
     private lateinit var topicDao: TopicDao
@@ -56,7 +60,7 @@ class OfflineFirstTopicsRepositoryTest {
         topicDao = TestTopicDao()
         network = TestNiaNetworkDataSource()
         niaPreferences = NiaPreferencesDataSource(
-            tmpFolder.testUserPreferencesDataStore(),
+            tmpFolder.testUserPreferencesDataStore(testScope),
         )
         synchronizer = TestSynchronizer(niaPreferences)
 
@@ -68,7 +72,7 @@ class OfflineFirstTopicsRepositoryTest {
 
     @Test
     fun offlineFirstTopicsRepository_topics_stream_is_backed_by_topics_dao() =
-        runTest {
+        testScope.runTest {
             assertEquals(
                 topicDao.getTopicEntities()
                     .first()
@@ -80,7 +84,7 @@ class OfflineFirstTopicsRepositoryTest {
 
     @Test
     fun offlineFirstTopicsRepository_sync_pulls_from_network() =
-        runTest {
+        testScope.runTest {
             subject.syncWith(synchronizer)
 
             val networkTopics = network.getTopics()
@@ -103,7 +107,7 @@ class OfflineFirstTopicsRepositoryTest {
 
     @Test
     fun offlineFirstTopicsRepository_incremental_sync_pulls_from_network() =
-        runTest {
+        testScope.runTest {
             // Set topics version to 10
             synchronizer.updateChangeListVersions {
                 copy(topicVersion = 10)
@@ -133,7 +137,7 @@ class OfflineFirstTopicsRepositoryTest {
 
     @Test
     fun offlineFirstTopicsRepository_sync_deletes_items_marked_deleted_on_network() =
-        runTest {
+        testScope.runTest {
             val networkTopics = network.getTopics()
                 .map(NetworkTopic::asEntity)
                 .map(TopicEntity::asExternalModel)

core/data/src/test/java/com/google/samples/apps/nowinandroid/core/data/repository/OfflineFirstUserDataRepositoryTest.kt

@@ -24,6 +24,8 @@ import com.google.samples.apps.nowinandroid.core.model.data.ThemeBrand
 import com.google.samples.apps.nowinandroid.core.model.data.UserData
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
 import org.junit.Rule
@@ -34,6 +36,9 @@ import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 class OfflineFirstUserDataRepositoryTest {
+
+    private val testScope = TestScope(UnconfinedTestDispatcher())
+
     private lateinit var subject: OfflineFirstUserDataRepository
 
     private lateinit var niaPreferencesDataSource: NiaPreferencesDataSource
@@ -46,7 +51,7 @@ class OfflineFirstUserDataRepositoryTest {
     @Before
     fun setup() {
         niaPreferencesDataSource = NiaPreferencesDataSource(
-            tmpFolder.testUserPreferencesDataStore(),
+            tmpFolder.testUserPreferencesDataStore(testScope),
         )
 
         subject = OfflineFirstUserDataRepository(
@@ -57,7 +62,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_default_user_data_is_correct() =
-        runTest {
+        testScope.runTest {
             assertEquals(
                 UserData(
                     bookmarkedNewsResources = emptySet(),
@@ -73,7 +78,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_toggle_followed_topics_logic_delegates_to_nia_preferences() =
-        runTest {
+        testScope.runTest {
             subject.toggleFollowedTopicId(followedTopicId = "0", followed = true)
 
             assertEquals(
@@ -104,7 +109,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_set_followed_topics_logic_delegates_to_nia_preferences() =
-        runTest {
+        testScope.runTest {
             subject.setFollowedTopicIds(followedTopicIds = setOf("1", "2"))
 
             assertEquals(
@@ -126,7 +131,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_bookmark_news_resource_logic_delegates_to_nia_preferences() =
-        runTest {
+        testScope.runTest {
             subject.updateNewsResourceBookmark(newsResourceId = "0", bookmarked = true)
 
             assertEquals(
@@ -157,7 +162,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_set_theme_brand_delegates_to_nia_preferences() =
-        runTest {
+        testScope.runTest {
             subject.setThemeBrand(ThemeBrand.ANDROID)
 
             assertEquals(
@@ -177,7 +182,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_set_dynamic_color_delegates_to_nia_preferences() =
-        runTest {
+        testScope.runTest {
             subject.setDynamicColorPreference(true)
 
             assertEquals(
@@ -197,7 +202,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun offlineFirstUserDataRepository_set_dark_theme_config_delegates_to_nia_preferences() =
-        runTest {
+        testScope.runTest {
             subject.setDarkThemeConfig(DarkThemeConfig.DARK)
 
             assertEquals(
@@ -217,7 +222,7 @@ class OfflineFirstUserDataRepositoryTest {
 
     @Test
     fun whenUserCompletesOnboarding_thenRemovesAllInterests_shouldHideOnboardingIsFalse() =
-        runTest {
+        testScope.runTest {
             subject.setFollowedTopicIds(setOf("1"))
             subject.setShouldHideOnboarding(true)
             assertTrue(subject.userData.first().shouldHideOnboarding)

core/datastore-test/build.gradle.kts

@@ -24,6 +24,7 @@ android {
 
 dependencies {
     api(project(":core:datastore"))
+    implementation(project(":core:common"))
     implementation(project(":core:testing"))
 
     api(libs.androidx.dataStore.core)

core/datastore-test/src/main/java/com/google/samples/apps/nowinandroid/core/datastore/test/TestDataStoreModule.kt

@@ -21,10 +21,15 @@ import androidx.datastore.core.DataStoreFactory
 import com.google.samples.apps.nowinandroid.core.datastore.UserPreferences
 import com.google.samples.apps.nowinandroid.core.datastore.UserPreferencesSerializer
 import com.google.samples.apps.nowinandroid.core.datastore.di.DataStoreModule
+import com.google.samples.apps.nowinandroid.core.network.Dispatcher
+import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.IO
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.components.SingletonComponent
 import dagger.hilt.testing.TestInstallIn
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
 import org.junit.rules.TemporaryFolder
 import javax.inject.Singleton
 
@@ -38,16 +43,23 @@ object TestDataStoreModule {
     @Provides
     @Singleton
     fun providesUserPreferencesDataStore(
+        @Dispatcher(IO) ioDispatcher: CoroutineDispatcher,
         userPreferencesSerializer: UserPreferencesSerializer,
         tmpFolder: TemporaryFolder,
     ): DataStore<UserPreferences> =
-        tmpFolder.testUserPreferencesDataStore(userPreferencesSerializer)
+        tmpFolder.testUserPreferencesDataStore(
+            // TODO: Provide an application-wide CoroutineScope in the DI graph
+            coroutineScope = CoroutineScope(SupervisorJob() + ioDispatcher),
+            userPreferencesSerializer = userPreferencesSerializer
+        )
 }
 
 fun TemporaryFolder.testUserPreferencesDataStore(
+    coroutineScope: CoroutineScope,
     userPreferencesSerializer: UserPreferencesSerializer = UserPreferencesSerializer(),
 ) = DataStoreFactory.create(
     serializer = userPreferencesSerializer,
+    scope = coroutineScope
 ) {
     newFile("user_preferences_test.pb")
 }

core/datastore/src/test/java/com/google/samples/apps/nowinandroid/core/datastore/NiaPreferencesDataSourceTest.kt

@@ -18,6 +18,8 @@ package com.google.samples.apps.nowinandroid.core.datastore
 
 import com.google.samples.apps.nowinandroid.core.datastore.test.testUserPreferencesDataStore
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
 import org.junit.Rule
@@ -27,6 +29,9 @@ import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 class NiaPreferencesDataSourceTest {
+
+    private val testScope = TestScope(UnconfinedTestDispatcher())
+
     private lateinit var subject: NiaPreferencesDataSource
 
     @get:Rule
@@ -35,23 +40,24 @@ class NiaPreferencesDataSourceTest {
     @Before
     fun setup() {
         subject = NiaPreferencesDataSource(
-            tmpFolder.testUserPreferencesDataStore(),
+            tmpFolder.testUserPreferencesDataStore(testScope),
         )
     }
 
     @Test
-    fun shouldHideOnboardingIsFalseByDefault() = runTest {
+    fun shouldHideOnboardingIsFalseByDefault() = testScope.runTest {
         assertFalse(subject.userData.first().shouldHideOnboarding)
     }
 
     @Test
-    fun userShouldHideOnboardingIsTrueWhenSet() = runTest {
+    fun userShouldHideOnboardingIsTrueWhenSet() = testScope.runTest {
         subject.setShouldHideOnboarding(true)
         assertTrue(subject.userData.first().shouldHideOnboarding)
     }
 
     @Test
-    fun userShouldHideOnboarding_unfollowsLastTopic_shouldHideOnboardingIsFalse() = runTest {
+    fun userShouldHideOnboarding_unfollowsLastTopic_shouldHideOnboardingIsFalse() =
+        testScope.runTest {
             // Given: user completes onboarding by selecting a single topic.
             subject.toggleFollowedTopicId("1", true)
             subject.setShouldHideOnboarding(true)
@@ -64,7 +70,8 @@ class NiaPreferencesDataSourceTest {
         }
 
     @Test
-    fun userShouldHideOnboarding_unfollowsAllTopics_shouldHideOnboardingIsFalse() = runTest {
+    fun userShouldHideOnboarding_unfollowsAllTopics_shouldHideOnboardingIsFalse() =
+        testScope.runTest {
             // Given: user completes onboarding by selecting several topics.
             subject.setFollowedTopicIds(setOf("1", "2"))
             subject.setShouldHideOnboarding(true)
@@ -77,12 +84,12 @@ class NiaPreferencesDataSourceTest {
         }
 
     @Test
-    fun shouldUseDynamicColorFalseByDefault() = runTest {
+    fun shouldUseDynamicColorFalseByDefault() = testScope.runTest {
         assertFalse(subject.userData.first().useDynamicColor)
     }
 
     @Test
-    fun userShouldUseDynamicColorIsTrueWhenSet() = runTest {
+    fun userShouldUseDynamicColorIsTrueWhenSet() = testScope.runTest {
         subject.setDynamicColorPreference(true)
         assertTrue(subject.userData.first().useDynamicColor)
     }