Fix flaky test in TimelinePresenterTest (#7702)

The problem seemed to be sometimes the background work to switch from live timeline to a focused event timeline wasn't finished in time and an assertion failed from time to time.

By providing the coroutine to run this on we can pass a `TestScope` and force it to reliably run immediately instead in unit tests.

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesNode.kt

@@ -51,6 +51,7 @@ import io.element.android.libraries.androidutils.system.toast
 import io.element.android.libraries.architecture.NodeInputs
 import io.element.android.libraries.architecture.callback
 import io.element.android.libraries.architecture.inputs
+import io.element.android.libraries.core.coroutine.CoroutineDispatchers
 import io.element.android.libraries.designsystem.utils.OnLifecycleEvent
 import io.element.android.libraries.di.RoomScope
 import io.element.android.libraries.di.annotations.ApplicationContext
@@ -103,6 +104,7 @@ class MessagesNode(
     private val roomMemberModerationRenderer: RoomMemberModerationRenderer,
     private val eventContentValidationCache: EventContentValidationCache,
     private val emojiPickerRenderer: EmojiPickerRenderer,
+    private val dispatchers: CoroutineDispatchers,
 ) : Node(buildContext, plugins = plugins), MessagesNavigator {
     data class Inputs(
         val focusedEventId: EventId?,
@@ -111,7 +113,12 @@ class MessagesNode(
     private val inputs = inputs<Inputs>()
     private val callback: Callback = callback()
 
-    private val timelineController = TimelineController(room, room.liveTimeline)
+    private val timelineController = TimelineController(
+        room = room,
+        liveTimeline = room.liveTimeline,
+        roomCoroutineScope = room.roomCoroutineScope,
+        dispatchers = dispatchers,
+    )
     private val presenter = presenterFactory.create(
         navigator = this,
         composerPresenter = messageComposerPresenterFactory.create(timelineController, this, threadRoot = null),

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/threads/ThreadedMessagesNode.kt

@@ -54,6 +54,7 @@ import io.element.android.libraries.architecture.NodeInputs
 import io.element.android.libraries.architecture.Presenter
 import io.element.android.libraries.architecture.callback
 import io.element.android.libraries.architecture.inputs
+import io.element.android.libraries.core.coroutine.CoroutineDispatchers
 import io.element.android.libraries.designsystem.utils.OnLifecycleEvent
 import io.element.android.libraries.di.RoomScope
 import io.element.android.libraries.emoji.api.picker.EmojiPickerRenderer
@@ -95,6 +96,7 @@ class ThreadedMessagesNode(
     private val appNavigationStateService: AppNavigationStateService,
     private val roomMemberModerationRenderer: RoomMemberModerationRenderer,
     private val emojiPickerRenderer: EmojiPickerRenderer,
+    private val dispatchers: CoroutineDispatchers,
 ) : Node(buildContext, plugins = plugins), MessagesNavigator {
     data class Inputs(
         val threadRootEventId: ThreadId,
@@ -113,7 +115,12 @@ class ThreadedMessagesNode(
      */
     private suspend fun createPresenter(): Presenter<MessagesState> {
         val threadedTimeline = room.createTimeline(CreateTimelineParams.Threaded(threadRootEventId = inputs.threadRootEventId)).getOrThrow()
-        val timelineController = TimelineController(room, threadedTimeline)
+        val timelineController = TimelineController(
+            room,
+            liveTimeline = threadedTimeline,
+            roomCoroutineScope = room.roomCoroutineScope,
+            dispatchers = dispatchers,
+        )
         this.timelineController = timelineController
         return presenterFactory.create(
             navigator = this,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineController.kt

@@ -12,7 +12,10 @@ import dev.zacsweers.metro.ContributesBinding
 import dev.zacsweers.metro.SingleIn
 import dev.zacsweers.metro.binding
 import io.element.android.features.messages.impl.timeline.di.LiveTimeline
+import io.element.android.libraries.core.coroutine.CoroutineDispatchers
+import io.element.android.libraries.core.coroutine.childScope
 import io.element.android.libraries.di.RoomScope
+import io.element.android.libraries.di.annotations.RoomCoroutineScope
 import io.element.android.libraries.matrix.api.core.EventId
 import io.element.android.libraries.matrix.api.core.ThreadId
 import io.element.android.libraries.matrix.api.room.CreateTimelineParams
@@ -23,7 +26,6 @@ import io.element.android.libraries.matrix.api.timeline.TimelineProvider
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -47,8 +49,10 @@ import java.util.Optional
 class TimelineController(
     private val room: JoinedRoom,
     @LiveTimeline private val liveTimeline: Timeline,
+    @RoomCoroutineScope private val roomCoroutineScope: CoroutineScope,
+    dispatchers: CoroutineDispatchers,
 ) : Closeable, TimelineProvider {
-    private val coroutineScope = CoroutineScope(SupervisorJob())
+    private val coroutineScope = roomCoroutineScope.childScope(dispatchers.computation, "TimelineController")
 
     private val liveTimelineFlow = flowOf(liveTimeline)
     private val detachedTimelineFlow = MutableStateFlow<Optional<Timeline>>(Optional.empty())

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/MessagesPresenterTest.kt

@@ -1484,7 +1484,12 @@ class MessagesPresenterTest {
             clipboardHelper = clipboardHelper,
             htmlConverterProvider = FakeHtmlConverterProvider(),
             buildMeta = aBuildMeta(),
-            timelineController = TimelineController(joinedRoom, timeline),
+            timelineController = TimelineController(
+                room = joinedRoom,
+                liveTimeline = timeline,
+                roomCoroutineScope = backgroundScope,
+                dispatchers = coroutineDispatchers,
+            ),
             permalinkParser = permalinkParser,
             analyticsService = analyticsService,
             encryptionService = encryptionService,

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/messagecomposer/MessageComposerPresenterSlashCommandTest.kt

@@ -65,6 +65,7 @@ import io.element.android.tests.testutils.WarmUpRule
 import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.lambda.value
 import io.element.android.tests.testutils.test
+import io.element.android.tests.testutils.testCoroutineDispatchers
 import io.mockk.mockk
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.TestScope
@@ -307,7 +308,12 @@ class MessageComposerPresenterSlashCommandTest {
         permissionsPresenterFactory = FakePermissionsPresenterFactory(permissionPresenter),
         permalinkParser = permalinkParser,
         permalinkBuilder = permalinkBuilder,
-        timelineController = TimelineController(room, timeline),
+        timelineController = TimelineController(
+            room = room,
+            liveTimeline = timeline,
+            roomCoroutineScope = backgroundScope,
+            dispatchers = testCoroutineDispatchers(),
+        ),
         draftService = draftService,
         mentionSpanProvider = mentionSpanProvider,
         pillificationHelper = textPillificationHelper,

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/messagecomposer/MessageComposerPresenterTest.kt

@@ -113,6 +113,7 @@ import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.lambda.value
 import io.element.android.tests.testutils.robolectric.RobolectricTest
 import io.element.android.tests.testutils.test
+import io.element.android.tests.testutils.testCoroutineDispatchers
 import io.element.android.tests.testutils.waitForPredicate
 import io.mockk.mockk
 import kotlinx.collections.immutable.ImmutableList
@@ -1707,7 +1708,12 @@ class MessageComposerPresenterTest : RobolectricTest() {
         permissionsPresenterFactory = FakePermissionsPresenterFactory(permissionPresenter),
         permalinkParser = permalinkParser,
         permalinkBuilder = permalinkBuilder,
-        timelineController = TimelineController(room, timeline),
+        timelineController = TimelineController(
+            room = room,
+            liveTimeline = timeline,
+            roomCoroutineScope = backgroundScope,
+            dispatchers = testCoroutineDispatchers(),
+        ),
         draftService = draftService,
         mentionSpanProvider = mentionSpanProvider,
         pillificationHelper = textPillificationHelper,

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/TimelineControllerTest.kt

@@ -21,8 +21,10 @@ import io.element.android.libraries.matrix.test.timeline.FakeTimeline
 import io.element.android.libraries.matrix.test.timeline.anEventTimelineItem
 import io.element.android.tests.testutils.lambda.lambdaError
 import io.element.android.tests.testutils.lambda.lambdaRecorder
+import io.element.android.tests.testutils.testCoroutineDispatchers
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.runTest
 import org.junit.Test
 
@@ -35,7 +37,10 @@ class TimelineControllerTest {
             liveTimeline = liveTimeline,
             createTimelineResult = { Result.success(detachedTimeline) }
         )
-        val sut = TimelineController(room = joinedRoom, liveTimeline = liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
 
         sut.activeTimelineFlow().test {
             awaitItem().also { state ->
@@ -74,7 +79,10 @@ class TimelineControllerTest {
                 }
             }
         )
-        val sut = TimelineController(joinedRoom, liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
 
         sut.activeTimelineFlow().test {
             awaitItem().also { state ->
@@ -102,7 +110,10 @@ class TimelineControllerTest {
         val joinedRoom = FakeJoinedRoom(
             liveTimeline = liveTimeline
         )
-        val sut = TimelineController(room = joinedRoom, liveTimeline = liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
         sut.activeTimelineFlow().test {
             awaitItem().also { state ->
                 assertThat(state).isEqualTo(liveTimeline)
@@ -121,7 +132,10 @@ class TimelineControllerTest {
             liveTimeline = liveTimeline,
             createTimelineResult = { Result.success(detachedTimeline) }
         )
-        val sut = TimelineController(room = joinedRoom, liveTimeline = liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
         sut.activeTimelineFlow().test {
             awaitItem().also { state ->
                 assertThat(state).isEqualTo(liveTimeline)
@@ -149,7 +163,10 @@ class TimelineControllerTest {
         val joinedRoom = FakeJoinedRoom(
             liveTimeline = liveTimeline
         )
-        val sut = TimelineController(room = joinedRoom, liveTimeline = liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
         assertThat(sut.timelineItems().first()).hasSize(1)
     }
 
@@ -171,7 +188,10 @@ class TimelineControllerTest {
             liveTimeline = liveTimeline,
             createTimelineResult = { Result.success(detachedTimeline) }
         )
-        val sut = TimelineController(room = joinedRoom, liveTimeline = liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
         sut.activeTimelineFlow().test {
             sut.focusOnEvent(AN_EVENT_ID, null)
             awaitItem().also { state ->
@@ -196,7 +216,10 @@ class TimelineControllerTest {
             liveTimeline = liveTimeline,
             createTimelineResult = { Result.success(detachedTimeline) }
         )
-        val sut = TimelineController(room = joinedRoom, liveTimeline = liveTimeline)
+        val sut = createTimelineController(
+            room = joinedRoom,
+            liveTimeline = liveTimeline,
+        )
 
         sut.activeTimelineFlow().test {
             awaitItem().also { state ->
@@ -220,12 +243,14 @@ class TimelineControllerTest {
     }
 }
 
-internal fun createTimelineController(
+internal fun TestScope.createTimelineController(
     room: FakeJoinedRoom = FakeJoinedRoom(liveTimeline = FakeTimeline()),
     liveTimeline: Timeline = FakeTimeline(name = "live"),
 ): TimelineController {
     return TimelineController(
         room = room,
-        liveTimeline = liveTimeline
+        liveTimeline = liveTimeline,
+        roomCoroutineScope = backgroundScope,
+        dispatchers = testCoroutineDispatchers(),
     )
 }

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenterTest.kt

@@ -1079,7 +1079,11 @@ class TimelinePresenterTest {
             val focusedState = consumeItemsUntilPredicate { it.focusRequestState == FocusRequestState.Success(AN_EVENT_ID) }.last()
             assertThat(focusedState.isLive).isFalse()
             initialState.eventSink.invoke(TimelineEvent.LoadMore(Timeline.PaginationDirection.FORWARDS))
-            advanceUntilIdle()
+
+            // Give some time for any potential pagination to be called, but it should not be called because the focused event is not rendered yet.
+            // Also, given enough time, a new state should be emitted with isLive = false, because we switched to a focused event timeline.
+            runCurrent()
+
             assert(paginateLambda).isNeverCalled()
             assertThat(expectMostRecentItem().isLive).isFalse()
         }
@@ -1906,7 +1910,12 @@ class TimelinePresenterTest {
             sendPollResponseAction = sendPollResponseAction,
             sessionPreferencesStore = sessionPreferencesStore,
             timelineItemIndexer = timelineItemIndexer,
-            timelineController = TimelineController(room, timeline),
+            timelineController = TimelineController(
+                room = room,
+                liveTimeline = timeline,
+                roomCoroutineScope = backgroundScope,
+                dispatchers = testCoroutineDispatchers(),
+            ),
             resolveVerifiedUserSendFailurePresenter = resolveVerifiedUserSendFailurePresenter,
             typingNotificationPresenter = { aTypingNotificationState() },
             roomCallStatePresenter = { aStandByCallState() },