Try using molecule

android/build.gradle

@@ -46,7 +46,7 @@ android {
                 storeFile file("release.keystore")
                 storePassword props['storePassword']
                 keyAlias props['keyAlias']
-                keyPassword  props['keyPassword']
+                keyPassword props['keyPassword']
             }
         }
     }
@@ -68,7 +68,8 @@ android {
         }
     }
     compileOptions {
-        coreLibraryDesugaringEnabled true // https://github.com/DroidKaigi/conference-app-2021/issues/373
+        // https://github.com/DroidKaigi/conference-app-2021/issues/373
+        coreLibraryDesugaringEnabled true
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
@@ -131,7 +132,12 @@ dependencies {
     implementation Dep.Kotlin.bom
     implementation Dep.Kotlin.stdlib
 
-    implementation (Dep.Coroutines.core) {
+    implementation(Dep.Coroutines.core) {
+        version {
+            strictly Versions.coroutines
+        }
+    }
+    testImplementation(Dep.Coroutines.core) {
         version {
             strictly Versions.coroutines
         }
@@ -165,7 +171,7 @@ dependencies {
     testImplementation 'io.kotest:kotest-assertions-core:4.3.2'
     // https://github.com/cashapp/turbine/issues/10
     testImplementation 'app.cash.turbine:turbine:0.2.1'
-
+    testImplementation Dep.turbine
     androidTestImplementation Dep.Jetpack.Test.ext
     androidTestImplementation Dep.Jetpack.Test.espresso
 }

android/src/test/java/io/github/droidkaigi/feeder/CoroutineTestRule.kt

@@ -1,19 +1,34 @@
 package io.github.droidkaigi.feeder
 
+import androidx.compose.runtime.BroadcastFrameClock
+import androidx.compose.runtime.withFrameMillis
+import androidx.lifecycle.overrideDefaultContext
+import kotlinx.coroutines.CoroutineStart
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.TestCoroutineDispatcher
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.setMain
+import kotlinx.coroutines.yield
 import org.junit.rules.TestWatcher
 import org.junit.runner.Description
 
 @ExperimentalCoroutinesApi
 class CoroutineTestRule(val testDispatcher: TestCoroutineDispatcher = TestCoroutineDispatcher()) :
     TestWatcher() {
+    private lateinit var clock: BroadcastFrameClock
+
+    suspend fun awaitFrame(){
+        yield()
+        clock.awaitFrame()
+    }
 
     override fun starting(description: Description?) {
         super.starting(description)
+        clock = BroadcastFrameClock()
+        overrideDefaultContext = clock + testDispatcher
         Dispatchers.setMain(testDispatcher)
     }
 
@@ -23,3 +38,19 @@ class CoroutineTestRule(val testDispatcher: TestCoroutineDispatcher = TestCorout
         testDispatcher.cleanupTestCoroutines()
     }
 }
+
+// from: molecule
+private suspend fun BroadcastFrameClock.awaitFrame() {
+    // TODO Remove the need for two frames to happen!
+    //  I think this is because of the diff-sender is a hot loop that immediately reschedules
+    //  itself on the clock. This schedules it ahead of the coroutine which applies changes and
+    //  so we need to trigger an additional frame to actually emit the change's diffs.
+    repeat(2) {
+        coroutineScope {
+            launch(start = CoroutineStart.UNDISPATCHED) {
+                withFrameMillis { }
+            }
+            sendFrame(0L)
+        }
+    }
+}

android/src/test/java/io/github/droidkaigi/feeder/FeedViewModelTest.kt

@@ -1,5 +1,6 @@
 package io.github.droidkaigi.feeder
 
+import app.cash.turbine.test
 import io.github.droidkaigi.feeder.data.FeedRepositoryImpl
 import io.github.droidkaigi.feeder.data.fakeFeedApi
 import io.github.droidkaigi.feeder.data.fakeFeedItemDao
@@ -32,63 +33,79 @@ class FeedViewModelTest(
     val coroutineTestRule = CoroutineTestRule()
 
     @Test
-    fun contents() = coroutineTestRule.testDispatcher.runBlockingTest {
-        // Replace when it fixed https://github.com/cashapp/turbine/issues/10
-        val feedViewModel = feedViewModelFactory.create()
-
-        val firstContent = feedViewModel.state.value.filteredFeedContents
-
-        firstContent.size shouldBeGreaterThan 1
+    fun contents() {
+        coroutineTestRule.testDispatcher.runBlockingTest {
+            val feedViewModel = feedViewModelFactory.create()
+            feedViewModel.state.test {
+                coroutineTestRule.awaitFrame()
+                expectMostRecentItem().filteredFeedContents.size shouldBeGreaterThan 1
+            }
+        }
     }
 
     @Test
     fun favorite_Add() = coroutineTestRule.testDispatcher.runBlockingTest {
         val feedViewModel = feedViewModelFactory.create()
-        val firstContent = feedViewModel.state.value.filteredFeedContents
-        firstContent.favorites shouldBe setOf()
+        feedViewModel.state.test {
+            coroutineTestRule.awaitFrame()
+            val firstContent = expectMostRecentItem().filteredFeedContents
+            firstContent.favorites shouldBe setOf()
 
-        feedViewModel.event(ToggleFavorite(firstContent.feedItemContents[0]))
+            feedViewModel.event(ToggleFavorite(firstContent.feedItemContents[0]))
 
-        val secondContent = feedViewModel.state.value.filteredFeedContents
-        secondContent.favorites shouldBe setOf(firstContent.feedItemContents[0].id)
+            coroutineTestRule.awaitFrame()
+            val secondContent = awaitItem().filteredFeedContents
+            secondContent.favorites shouldBe setOf(firstContent.feedItemContents[0].id)
+        }
     }
 
     @Test
     fun favorite_Remove() = coroutineTestRule.testDispatcher.runBlockingTest {
         val feedViewModel = feedViewModelFactory.create()
-        val firstContent = feedViewModel.state.value.filteredFeedContents
-        firstContent.favorites shouldBe setOf()
-
-        feedViewModel.event(ToggleFavorite(feedItem = firstContent.feedItemContents[0]))
-        feedViewModel.event(ToggleFavorite(feedItem = firstContent.feedItemContents[0]))
-
-        val secondContent = feedViewModel.state.value.filteredFeedContents
-        secondContent.favorites shouldBe setOf()
+        feedViewModel.state.test {
+            coroutineTestRule.awaitFrame()
+            val firstContent = expectMostRecentItem().filteredFeedContents
+            firstContent.favorites shouldBe setOf()
+
+            feedViewModel.event(ToggleFavorite(feedItem = firstContent.feedItemContents[0]))
+            coroutineTestRule.awaitFrame()
+            feedViewModel.event(ToggleFavorite(feedItem = firstContent.feedItemContents[0]))
+            coroutineTestRule.awaitFrame()
+
+            val secondContent = expectMostRecentItem().filteredFeedContents
+            secondContent.favorites shouldBe setOf()
+        }
     }
 
     @Test
     fun favorite_Filter() = coroutineTestRule.testDispatcher.runBlockingTest {
         val feedViewModel = feedViewModelFactory.create()
-        val firstContent = feedViewModel.state.value.filteredFeedContents
-        firstContent.favorites shouldBe setOf()
-        val favoriteContents = firstContent.feedItemContents[1]
-
-        feedViewModel.event(ToggleFavorite(feedItem = favoriteContents))
-        feedViewModel.event(ChangeFavoriteFilter(Filters(filterFavorite = true)))
-
-        val secondContent = feedViewModel.state.value.filteredFeedContents
-        secondContent.contents[0].first.id shouldBe favoriteContents.id
+        feedViewModel.state.test {
+            coroutineTestRule.awaitFrame()
+            val firstContent = expectMostRecentItem().filteredFeedContents
+            firstContent.favorites shouldBe setOf()
+            val favoriteContents = firstContent.feedItemContents[1]
+
+            feedViewModel.event(ToggleFavorite(feedItem = favoriteContents))
+            feedViewModel.event(ChangeFavoriteFilter(Filters(filterFavorite = true)))
+            coroutineTestRule.awaitFrame()
+
+            val secondContent = expectMostRecentItem().filteredFeedContents
+            secondContent.contents[0].first.id shouldBe favoriteContents.id
+        }
     }
 
     @Test
     fun errorWhenFetch() = coroutineTestRule.testDispatcher.runBlockingTest {
         val feedViewModel = feedViewModelFactory.create(errorFetchData = true)
-        val firstContent = feedViewModel.state.value.filteredFeedContents
-        firstContent.favorites shouldBe setOf()
+        feedViewModel.state.test {
+            val firstContent = expectMostRecentItem().filteredFeedContents
+            firstContent.favorites shouldBe setOf()
 
-        val firstEffect = feedViewModel.effect.first()
+            val firstEffect = feedViewModel.effect.first()
 
-        firstEffect.shouldBeInstanceOf<FeedViewModel.Effect.ErrorMessage>()
+            firstEffect.shouldBeInstanceOf<FeedViewModel.Effect.ErrorMessage>()
+        }
     }
 
     class FeedViewModelFactory(

build.gradle

@@ -27,6 +27,7 @@ buildscript {
         classpath Dep.SQLDelight.plugin
         classpath Dep.playServicesOssLicensesPlugin
         classpath Dep.buildKonfig
+        classpath Dep.Molecule.plugin
     }
 }
 

buildSrc/src/main/java/Dep.kt

@@ -150,4 +150,11 @@ object Dep {
     const val desugarJdkLibs = "com.android.tools:desugar_jdk_libs:1.1.5"
 
     const val napier = "io.github.aakira:napier:2.1.0"
+
+    object Molecule {
+        const val plugin = "app.cash.molecule:molecule-gradle-plugin:0.1.0"
+        const val runtime = "app.cash.molecule:molecule-runtime"
+        const val testing = "app.cash.molecule:molecule-testing:0.1.0"
+    }
+    val turbine = "app.cash.turbine:turbine:0.7.0"
 }

uicomponent-compose/core/build.gradle

@@ -7,6 +7,7 @@ plugins {
     id 'app.cash.exhaustive'
     id 'kotlin-kapt'
     id 'dagger.hilt.android.plugin'
+    id 'app.cash.molecule'
 }
 
 apply from: rootProject.file("gradle/android.gradle")

uicomponent-compose/core/src/main/java/androidx/lifecycle/viewModelScopeWithClock.kt

@@ -0,0 +1,34 @@
+package androidx.lifecycle
+
+import app.cash.molecule.AndroidUiDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import java.io.Closeable
+import kotlin.coroutines.CoroutineContext
+
+private const val JOB_KEY = "io.github.droidkaigi.feeder.ViewModelCoroutineScope.JOB_KEY"
+
+val defaultDispatcher by lazy { AndroidUiDispatcher.Main }
+var overrideDefaultContext: CoroutineContext? = null
+
+public val ViewModel.viewModelScopeWithClock: CoroutineScope
+    get() {
+        val scope: CoroutineScope? = this.getTag(JOB_KEY)
+        if (scope != null) {
+            return scope
+        }
+        return setTagIfAbsent(
+            JOB_KEY,
+            CloseableCoroutineScope(SupervisorJob() +
+                (overrideDefaultContext ?: defaultDispatcher))
+        )
+    }
+
+internal class CloseableCoroutineScope(context: CoroutineContext) : Closeable, CoroutineScope {
+    override val coroutineContext: CoroutineContext = context
+
+    override fun close() {
+        coroutineContext.cancel()
+    }
+}

uicomponent-compose/main/build.gradle

@@ -7,14 +7,16 @@ plugins {
     id 'kotlin-kapt'
     id 'app.cash.exhaustive'
     id 'dagger.hilt.android.plugin'
+    id 'app.cash.molecule'
 }
 
 apply from: rootProject.file("gradle/android.gradle")
 apply from: rootProject.file("gradle/compose.gradle")
 
 android {
     compileOptions {
-        coreLibraryDesugaringEnabled true // need for test. https://github.com/DroidKaigi/conference-app-2021/issues/373
+        coreLibraryDesugaringEnabled true
+        // need for test. https://github.com/DroidKaigi/conference-app-2021/issues/373
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
@@ -50,7 +52,7 @@ dependencies {
     implementation Dep.Accompanist.insets
     implementation Dep.Accompanist.systemuicontroller
 
-    implementation (Dep.Coroutines.core) {
+    implementation(Dep.Coroutines.core) {
         version {
             strictly Versions.coroutines
         }