From 39edc780fea7bfbabe003769f090bc80a7f3557f Mon Sep 17 00:00:00 2001
From: ganfra <francoisg@element.io>
Date: Mon, 27 Feb 2023 20:30:22 +0100
Subject: [PATCH] Makes sure to test loadMore method on TimelinePresenter

---
 .../messages/timeline/TimelinePresenter.kt    |  2 +-
 .../timeline/TimelinePresenterTest.kt         | 16 ++++++++----
 .../matrixtest/timeline/FakeMatrixTimeline.kt | 26 ++++++++++++++-----
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/features/messages/src/main/kotlin/io/element/android/features/messages/timeline/TimelinePresenter.kt b/features/messages/src/main/kotlin/io/element/android/features/messages/timeline/TimelinePresenter.kt
index b2cda24ff2..514ec34d78 100644
--- a/features/messages/src/main/kotlin/io/element/android/features/messages/timeline/TimelinePresenter.kt
+++ b/features/messages/src/main/kotlin/io/element/android/features/messages/timeline/TimelinePresenter.kt
@@ -55,7 +55,7 @@ class TimelinePresenter @Inject constructor(
         }
         val timelineItems = timelineItemsFactory
             .flow()
-            .collectAsState(emptyList())
+            .collectAsState()
 
         val paginationState = timeline
             .paginationState()
diff --git a/features/messages/src/test/kotlin/io/element/android/features/messages/timeline/TimelinePresenterTest.kt b/features/messages/src/test/kotlin/io/element/android/features/messages/timeline/TimelinePresenterTest.kt
index 12b5b649ed..bc1f90395d 100644
--- a/features/messages/src/test/kotlin/io/element/android/features/messages/timeline/TimelinePresenterTest.kt
+++ b/features/messages/src/test/kotlin/io/element/android/features/messages/timeline/TimelinePresenterTest.kt
@@ -42,6 +42,8 @@ class TimelinePresenterTest {
         }.test {
             val initialState = awaitItem()
             assertThat(initialState.timelineItems).isEmpty()
+            val loadedNoTimelineState = awaitItem()
+            assertThat(loadedNoTimelineState.timelineItems).isEmpty()
         }
     }
 
@@ -58,11 +60,14 @@ class TimelinePresenterTest {
         }.test {
             val initialState = awaitItem()
             assertThat(initialState.paginationState.canBackPaginate).isTrue()
-            matrixTimeline.updatePaginationState {
-                copy(canBackPaginate = false)
-            }
-            val loadedState = awaitItem()
-            assertThat(loadedState.paginationState.canBackPaginate).isFalse()
+            assertThat(initialState.paginationState.isBackPaginating).isFalse()
+            initialState.eventSink.invoke(TimelineEvents.LoadMore)
+            val inPaginationState = awaitItem()
+            assertThat(inPaginationState.paginationState.isBackPaginating).isTrue()
+            assertThat(inPaginationState.paginationState.canBackPaginate).isTrue()
+            val postPaginationState = awaitItem()
+            assertThat(postPaginationState.paginationState.canBackPaginate).isTrue()
+            assertThat(postPaginationState.paginationState.isBackPaginating).isFalse()
         }
     }
 
@@ -78,6 +83,7 @@ class TimelinePresenterTest {
             presenter.present()
         }.test {
             val initialState = awaitItem()
+            skipItems(1)
             assertThat(initialState.highlightedEventId).isNull()
             initialState.eventSink.invoke(TimelineEvents.SetHighlightedEvent(AN_EVENT_ID))
             val withHighlightedState = awaitItem()
diff --git a/libraries/matrixtest/src/main/kotlin/io/element/android/libraries/matrixtest/timeline/FakeMatrixTimeline.kt b/libraries/matrixtest/src/main/kotlin/io/element/android/libraries/matrixtest/timeline/FakeMatrixTimeline.kt
index bdf4c6dc16..9f8e2aa8ba 100644
--- a/libraries/matrixtest/src/main/kotlin/io/element/android/libraries/matrixtest/timeline/FakeMatrixTimeline.kt
+++ b/libraries/matrixtest/src/main/kotlin/io/element/android/libraries/matrixtest/timeline/FakeMatrixTimeline.kt
@@ -23,28 +23,42 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.emptyFlow
 
-class FakeMatrixTimeline : MatrixTimeline {
+class FakeMatrixTimeline(
+    initialTimelineItems: List<MatrixTimelineItem> = emptyList(),
+    initialPaginationState: MatrixTimeline.PaginationState = MatrixTimeline.PaginationState(canBackPaginate = true, isBackPaginating = false)
+) : MatrixTimeline {
 
-    private val paginationState = MutableStateFlow(
-        MatrixTimeline.PaginationState(canBackPaginate = true, isBackPaginating = false)
-    )
+    private val paginationState: MutableStateFlow<MatrixTimeline.PaginationState> = MutableStateFlow(initialPaginationState)
+    private val timelineItems: MutableStateFlow<List<MatrixTimelineItem>> = MutableStateFlow(initialTimelineItems)
 
     fun updatePaginationState(update: (MatrixTimeline.PaginationState.() -> MatrixTimeline.PaginationState)) {
         paginationState.value = update(paginationState.value)
     }
 
+    fun updateTimelineItems(update: (items: List<MatrixTimelineItem>) -> List<MatrixTimelineItem>) {
+        timelineItems.value = update(timelineItems.value)
+    }
+
     override fun paginationState(): StateFlow<MatrixTimeline.PaginationState> {
         return paginationState
     }
 
     override fun timelineItems(): Flow<List<MatrixTimelineItem>> {
-        return emptyFlow()
+        return timelineItems
     }
 
     override suspend fun paginateBackwards(requestSize: Int, untilNumberOfItems: Int): Result<Unit> {
+        updatePaginationState {
+            copy(isBackPaginating = true)
+        }
         delay(100)
+        updatePaginationState {
+            copy(isBackPaginating = false)
+        }
+        updateTimelineItems { timelineItems ->
+            timelineItems
+        }
         return Result.success(Unit)
     }