Fix Windows unit test failing because of DataStore threading issue

app/build.gradle.kts

@@ -114,6 +114,7 @@ dependencies {
     kspTest(libs.hilt.compiler)
 
     testImplementation(projects.core.dataTest)
+    testImplementation(projects.core.datastoreTest)
     testImplementation(libs.hilt.android.testing)
     testImplementation(projects.sync.syncTest)
     testImplementation(libs.kotlin.test)

app/src/androidTest/kotlin/com/google/samples/apps/nowinandroid/ui/NavigationTest.kt

@@ -35,15 +35,13 @@ import com.google.samples.apps.nowinandroid.R
 import com.google.samples.apps.nowinandroid.core.data.repository.TopicsRepository
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.rules.GrantPostNotificationsPermissionRule
-import dagger.hilt.android.testing.BindValue
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.runBlocking
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import javax.inject.Inject
 import com.google.samples.apps.nowinandroid.feature.bookmarks.R as BookmarksR
 import com.google.samples.apps.nowinandroid.feature.foryou.R as FeatureForyouR
@@ -62,24 +60,16 @@ class NavigationTest {
     @get:Rule(order = 0)
     val hiltRule = HiltAndroidRule(this)
 
-    /**
-     * Create a temporary folder used to create a Data Store file. This guarantees that
-     * the file is removed in between each test, preventing a crash.
-     */
-    @BindValue
-    @get:Rule(order = 1)
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     /**
      * Grant [android.Manifest.permission.POST_NOTIFICATIONS] permission.
      */
-    @get:Rule(order = 2)
+    @get:Rule(order = 1)
     val postNotificationsPermission = GrantPostNotificationsPermissionRule()
 
     /**
      * Use the primary activity to initialize the app normally.
      */
-    @get:Rule(order = 3)
+    @get:Rule(order = 2)
     val composeTestRule = createAndroidComposeRule<MainActivity>()
 
     @Inject

app/src/testDemo/kotlin/com/google/samples/apps/nowinandroid/ui/InterestsListDetailScreenTest.kt

@@ -31,7 +31,6 @@ import com.google.samples.apps.nowinandroid.core.designsystem.theme.NiaTheme
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.ui.interests2pane.InterestsListDetailScreen
 import com.google.samples.apps.nowinandroid.uitesthiltmanifest.HiltComponentActivity
-import dagger.hilt.android.testing.BindValue
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import dagger.hilt.android.testing.HiltTestApplication
@@ -40,7 +39,6 @@ import kotlinx.coroutines.runBlocking
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
@@ -60,11 +58,7 @@ class InterestsListDetailScreenTest {
     @get:Rule(order = 0)
     val hiltRule = HiltAndroidRule(this)
 
-    @BindValue
     @get:Rule(order = 1)
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
-    @get:Rule(order = 2)
     val composeTestRule = createAndroidComposeRule<HiltComponentActivity>()
 
     @Inject

app/src/testDemo/kotlin/com/google/samples/apps/nowinandroid/ui/NiaAppScreenSizesScreenshotTests.kt

@@ -38,7 +38,6 @@ import com.google.samples.apps.nowinandroid.core.data.util.TimeZoneMonitor
 import com.google.samples.apps.nowinandroid.core.designsystem.theme.NiaTheme
 import com.google.samples.apps.nowinandroid.core.testing.util.DefaultRoborazziOptions
 import com.google.samples.apps.nowinandroid.uitesthiltmanifest.HiltComponentActivity
-import dagger.hilt.android.testing.BindValue
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import dagger.hilt.android.testing.HiltTestApplication
@@ -47,7 +46,6 @@ import kotlinx.coroutines.runBlocking
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
@@ -74,18 +72,10 @@ class NiaAppScreenSizesScreenshotTests {
     @get:Rule(order = 0)
     val hiltRule = HiltAndroidRule(this)
 
-    /**
-     * Create a temporary folder used to create a Data Store file. This guarantees that
-     * the file is removed in between each test, preventing a crash.
-     */
-    @BindValue
-    @get:Rule(order = 1)
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     /**
      * Use a test activity to set the content on.
      */
-    @get:Rule(order = 2)
+    @get:Rule(order = 1)
     val composeTestRule = createAndroidComposeRule<HiltComponentActivity>()
 
     @Inject

app/src/testDemo/kotlin/com/google/samples/apps/nowinandroid/ui/SnackbarInsetsScreenshotTests.kt

@@ -69,7 +69,6 @@ import com.google.samples.apps.nowinandroid.core.data.util.TimeZoneMonitor
 import com.google.samples.apps.nowinandroid.core.designsystem.theme.NiaTheme
 import com.google.samples.apps.nowinandroid.core.testing.util.DefaultRoborazziOptions
 import com.google.samples.apps.nowinandroid.uitesthiltmanifest.HiltComponentActivity
-import dagger.hilt.android.testing.BindValue
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import dagger.hilt.android.testing.HiltTestApplication
@@ -80,7 +79,6 @@ import kotlinx.coroutines.runBlocking
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
@@ -107,18 +105,10 @@ class SnackbarInsetsScreenshotTests {
     @get:Rule(order = 0)
     val hiltRule = HiltAndroidRule(this)
 
-    /**
-     * Create a temporary folder used to create a Data Store file. This guarantees that
-     * the file is removed in between each test, preventing a crash.
-     */
-    @BindValue
-    @get:Rule(order = 1)
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     /**
      * Use a test activity to set the content on.
      */
-    @get:Rule(order = 2)
+    @get:Rule(order = 1)
     val composeTestRule = createAndroidComposeRule<HiltComponentActivity>()
 
     @Inject

app/src/testDemo/kotlin/com/google/samples/apps/nowinandroid/ui/SnackbarScreenshotTests.kt

@@ -42,7 +42,6 @@ import com.google.samples.apps.nowinandroid.core.data.util.TimeZoneMonitor
 import com.google.samples.apps.nowinandroid.core.designsystem.theme.NiaTheme
 import com.google.samples.apps.nowinandroid.core.testing.util.DefaultRoborazziOptions
 import com.google.samples.apps.nowinandroid.uitesthiltmanifest.HiltComponentActivity
-import dagger.hilt.android.testing.BindValue
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import dagger.hilt.android.testing.HiltTestApplication
@@ -53,7 +52,6 @@ import kotlinx.coroutines.runBlocking
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
@@ -80,18 +78,10 @@ class SnackbarScreenshotTests {
     @get:Rule(order = 0)
     val hiltRule = HiltAndroidRule(this)
 
-    /**
-     * Create a temporary folder used to create a Data Store file. This guarantees that
-     * the file is removed in between each test, preventing a crash.
-     */
-    @BindValue
-    @get:Rule(order = 1)
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     /**
      * Use a test activity to set the content on.
      */
-    @get:Rule(order = 2)
+    @get:Rule(order = 1)
     val composeTestRule = createAndroidComposeRule<HiltComponentActivity>()
 
     @Inject

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

@@ -32,7 +32,8 @@ import com.google.samples.apps.nowinandroid.core.database.model.PopulatedNewsRes
 import com.google.samples.apps.nowinandroid.core.database.model.TopicEntity
 import com.google.samples.apps.nowinandroid.core.database.model.asExternalModel
 import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
-import com.google.samples.apps.nowinandroid.core.datastore.test.testUserPreferencesDataStore
+import com.google.samples.apps.nowinandroid.core.datastore.UserPreferences
+import com.google.samples.apps.nowinandroid.core.datastore.test.InMemoryDataStore
 import com.google.samples.apps.nowinandroid.core.model.data.NewsResource
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.network.model.NetworkChangeList
@@ -43,9 +44,7 @@ import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
-import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
@@ -67,14 +66,9 @@ class OfflineFirstNewsRepositoryTest {
 
     private lateinit var synchronizer: Synchronizer
 
-    @get:Rule
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     @Before
     fun setup() {
-        niaPreferencesDataSource = NiaPreferencesDataSource(
-            tmpFolder.testUserPreferencesDataStore(testScope.backgroundScope),
-        )
+        niaPreferencesDataSource = NiaPreferencesDataSource(InMemoryDataStore(UserPreferences.getDefaultInstance()))
         newsResourceDao = TestNewsResourceDao()
         topicDao = TestTopicDao()
         network = TestNiaNetworkDataSource()

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

@@ -25,17 +25,16 @@ import com.google.samples.apps.nowinandroid.core.database.dao.TopicDao
 import com.google.samples.apps.nowinandroid.core.database.model.TopicEntity
 import com.google.samples.apps.nowinandroid.core.database.model.asExternalModel
 import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
-import com.google.samples.apps.nowinandroid.core.datastore.test.testUserPreferencesDataStore
+import com.google.samples.apps.nowinandroid.core.datastore.UserPreferences
+import com.google.samples.apps.nowinandroid.core.datastore.test.InMemoryDataStore
 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
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import kotlin.test.assertEquals
 
 class OfflineFirstTopicsRepositoryTest {
@@ -52,16 +51,11 @@ class OfflineFirstTopicsRepositoryTest {
 
     private lateinit var synchronizer: Synchronizer
 
-    @get:Rule
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     @Before
     fun setup() {
         topicDao = TestTopicDao()
         network = TestNiaNetworkDataSource()
-        niaPreferences = NiaPreferencesDataSource(
-            tmpFolder.testUserPreferencesDataStore(testScope.backgroundScope),
-        )
+        niaPreferences = NiaPreferencesDataSource(InMemoryDataStore(UserPreferences.getDefaultInstance()))
         synchronizer = TestSynchronizer(niaPreferences)
 
         subject = OfflineFirstTopicsRepository(

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

@@ -18,7 +18,8 @@ package com.google.samples.apps.nowinandroid.core.data.repository
 
 import com.google.samples.apps.nowinandroid.core.analytics.NoOpAnalyticsHelper
 import com.google.samples.apps.nowinandroid.core.datastore.NiaPreferencesDataSource
-import com.google.samples.apps.nowinandroid.core.datastore.test.testUserPreferencesDataStore
+import com.google.samples.apps.nowinandroid.core.datastore.UserPreferences
+import com.google.samples.apps.nowinandroid.core.datastore.test.InMemoryDataStore
 import com.google.samples.apps.nowinandroid.core.model.data.DarkThemeConfig
 import com.google.samples.apps.nowinandroid.core.model.data.ThemeBrand
 import com.google.samples.apps.nowinandroid.core.model.data.UserData
@@ -28,9 +29,7 @@ import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
-import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TemporaryFolder
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
@@ -45,14 +44,9 @@ class OfflineFirstUserDataRepositoryTest {
 
     private val analyticsHelper = NoOpAnalyticsHelper()
 
-    @get:Rule
-    val tmpFolder: TemporaryFolder = TemporaryFolder.builder().assureDeletion().build()
-
     @Before
     fun setup() {
-        niaPreferencesDataSource = NiaPreferencesDataSource(
-            tmpFolder.testUserPreferencesDataStore(testScope.backgroundScope),
-        )
+        niaPreferencesDataSource = NiaPreferencesDataSource(InMemoryDataStore(UserPreferences.getDefaultInstance()))
 
         subject = OfflineFirstUserDataRepository(
             niaPreferencesDataSource = niaPreferencesDataSource,

core/datastore-test/src/main/kotlin/com/google/samples/apps/nowinandroid/core/datastore/test/InMemoryDataStore.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2024 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.datastore.test
+
+import androidx.datastore.core.DataStore
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.updateAndGet
+
+class InMemoryDataStore<T>(initialValue: T) : DataStore<T> {
+    override val data = MutableStateFlow(initialValue)
+    override suspend fun updateData(
+        transform: suspend (it: T) -> T,
+    ) = data.updateAndGet { transform(it) }
+}

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

@@ -17,17 +17,13 @@
 package com.google.samples.apps.nowinandroid.core.datastore.test
 
 import androidx.datastore.core.DataStore
-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.di.ApplicationScope
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.components.SingletonComponent
 import dagger.hilt.testing.TestInstallIn
-import kotlinx.coroutines.CoroutineScope
-import org.junit.rules.TemporaryFolder
 import javax.inject.Singleton
 
 @Module
@@ -36,26 +32,9 @@ import javax.inject.Singleton
     replaces = [DataStoreModule::class],
 )
 internal object TestDataStoreModule {
-
     @Provides
     @Singleton
     fun providesUserPreferencesDataStore(
-        @ApplicationScope scope: CoroutineScope,
-        userPreferencesSerializer: UserPreferencesSerializer,
-        tmpFolder: TemporaryFolder,
-    ): DataStore<UserPreferences> =
-        tmpFolder.testUserPreferencesDataStore(
-            coroutineScope = scope,
-            userPreferencesSerializer = userPreferencesSerializer,
-        )
-}
-
-fun TemporaryFolder.testUserPreferencesDataStore(
-    coroutineScope: CoroutineScope,
-    userPreferencesSerializer: UserPreferencesSerializer = UserPreferencesSerializer(),
-) = DataStoreFactory.create(
-    serializer = userPreferencesSerializer,
-    scope = coroutineScope,
-) {
-    newFile("user_preferences_test.pb")
+        serializer: UserPreferencesSerializer,
+    ): DataStore<UserPreferences> = InMemoryDataStore(serializer.defaultValue)
 }