Create test for DateTimeObserver usage in RoomListDataSource

features/roomlist/impl/src/test/kotlin/io/element/android/features/roomlist/impl/RoomListPresenterTest.kt

@@ -677,7 +677,7 @@ class RoomListPresenterTest {
 }
 
 class FakeDateTimeObserver : DateTimeObserver {
-    override val changes = MutableSharedFlow<DateTimeObserver.Event>()
+    override val changes = MutableSharedFlow<DateTimeObserver.Event>(extraBufferCapacity = 1)
 
     fun given(event: DateTimeObserver.Event) {
         changes.tryEmit(event)

features/roomlist/impl/src/test/kotlin/io/element/android/features/roomlist/impl/datasource/RoomListDataSourceTest.kt

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2024 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Please see LICENSE in the repository root for full details.
+ */
+
+package io.element.android.features.roomlist.impl.datasource
+
+import app.cash.turbine.test
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.roomlist.impl.FakeDateTimeObserver
+import io.element.android.libraries.androidutils.system.DateTimeObserver
+import io.element.android.libraries.core.coroutine.CoroutineDispatchers
+import io.element.android.libraries.dateformatter.api.LastMessageTimestampFormatter
+import io.element.android.libraries.eventformatter.api.RoomLastMessageFormatter
+import io.element.android.libraries.matrix.api.roomlist.RoomListService
+import io.element.android.libraries.matrix.test.notificationsettings.FakeNotificationSettingsService
+import io.element.android.libraries.matrix.test.room.aRoomSummary
+import io.element.android.libraries.matrix.test.roomlist.FakeRoomListService
+import io.element.android.tests.testutils.testCoroutineDispatchers
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.runTest
+import org.junit.Test
+import java.time.Instant
+
+class RoomListDataSourceTest {
+    @Test
+    fun `when DateTimeObserver gets a date change, the room summaries are refreshed`() = runTest {
+        val roomListService = FakeRoomListService().apply {
+            postState(RoomListService.State.Running)
+            postAllRooms(listOf(aRoomSummary()))
+        }
+        val dateTimeObserver = FakeDateTimeObserver()
+        val roomListDataSource = createRoomListDataSource(roomListService = roomListService, dateTimeObserver = dateTimeObserver)
+
+        roomListDataSource.allRooms.test {
+            // Observe room list items changes
+            roomListDataSource.launchIn(backgroundScope)
+
+            // Get the initial room list
+            val initialRoomList = awaitItem()
+            assertThat(initialRoomList).isNotEmpty()
+
+            // Trigger a date change
+            dateTimeObserver.given(DateTimeObserver.Event.DateChanged(Instant.MIN, Instant.now()))
+
+            // Check there is a new list and it's not the same as the previous one (although it has the same content)
+            val newRoomList = awaitItem()
+            assertThat(newRoomList).isNotSameInstanceAs(initialRoomList)
+
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `when DateTimeObserver gets a time zone change, the room summaries are refreshed`() = runTest {
+        val roomListService = FakeRoomListService().apply {
+            postState(RoomListService.State.Running)
+            postAllRooms(listOf(aRoomSummary()))
+        }
+        val dateTimeObserver = FakeDateTimeObserver()
+        val roomListDataSource = createRoomListDataSource(roomListService = roomListService, dateTimeObserver = dateTimeObserver)
+
+        roomListDataSource.allRooms.test {
+            // Observe room list items changes
+            roomListDataSource.launchIn(backgroundScope)
+
+            // Get the initial room list
+            val initialRoomList = awaitItem()
+            assertThat(initialRoomList).isNotEmpty()
+
+            // Trigger a timezone change
+            dateTimeObserver.given(DateTimeObserver.Event.TimeZoneChanged)
+
+            // Check there is a new list and it's not the same as the previous one (although it has the same content)
+            val newRoomList = awaitItem()
+            assertThat(newRoomList).isNotSameInstanceAs(initialRoomList)
+
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    private fun TestScope.createRoomListDataSource(
+        roomListService: FakeRoomListService = FakeRoomListService(),
+        roomListRoomSummaryFactory: RoomListRoomSummaryFactory =
+        RoomListRoomSummaryFactory(
+            lastMessageTimestampFormatter = LastMessageTimestampFormatter { _ -> "Yesterday" },
+            roomLastMessageFormatter = RoomLastMessageFormatter { _, _ -> "Hey" }
+        ),
+        dispatchers: CoroutineDispatchers = testCoroutineDispatchers(),
+        notificationSettingsService: FakeNotificationSettingsService = FakeNotificationSettingsService(),
+        appScope: CoroutineScope = backgroundScope,
+        dateTimeObserver: FakeDateTimeObserver = FakeDateTimeObserver(),
+    ) = RoomListDataSource(
+        roomListService = roomListService,
+        roomListRoomSummaryFactory = roomListRoomSummaryFactory,
+        coroutineDispatchers = dispatchers,
+        notificationSettingsService = notificationSettingsService,
+        appScope = appScope,
+        dateTimeObserver = dateTimeObserver,
+    )
+}

libraries/dateformatter/api/src/main/kotlin/io/element/android/libraries/dateformatter/api/LastMessageTimestampFormatter.kt

@@ -7,6 +7,6 @@
 
 package io.element.android.libraries.dateformatter.api
 
-interface LastMessageTimestampFormatter {
+fun interface LastMessageTimestampFormatter {
     fun format(timestamp: Long?): String
 }

libraries/eventformatter/api/src/main/kotlin/io/element/android/libraries/eventformatter/api/RoomLastMessageFormatter.kt

@@ -9,6 +9,6 @@ package io.element.android.libraries.eventformatter.api
 
 import io.element.android.libraries.matrix.api.timeline.item.event.EventTimelineItem
 
-interface RoomLastMessageFormatter {
+fun interface RoomLastMessageFormatter {
     fun format(event: EventTimelineItem, isDmRoom: Boolean): CharSequence?
 }