#352: Add basic UI tests for the timeline. (#363)

Makes the MockTimelineController configurable with incoming items and pagination responses.

ElementX.xcodeproj/project.pbxproj

@@ -208,6 +208,7 @@
 		6FC10A00D268FCD48B631E37 /* ViewFrameReader.swift in Sources */ = {isa = PBXBuildFile; fileRef = EFF7BF82A950B91BC5469E91 /* ViewFrameReader.swift */; };
 		7002C55A4C917F3715765127 /* MediaProviderProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = C888BCD78E2A55DCE364F160 /* MediaProviderProtocol.swift */; };
 		702694459B649B9D3A3C34F8 /* TimelineTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = F9212AE02CBDD692C56A879F /* TimelineTableViewController.swift */; };
+		70558528EF68CAAEF09972D5 /* RoomTimelineItemFixtures.swift in Sources */ = {isa = PBXBuildFile; fileRef = E96ED747FF90332EA1333C22 /* RoomTimelineItemFixtures.swift */; };
 		706F79A39BDB32F592B8C2C7 /* UIKitBackgroundTask.swift in Sources */ = {isa = PBXBuildFile; fileRef = 92FCD9116ADDE820E4E30F92 /* UIKitBackgroundTask.swift */; };
 		7096FA3AC218D914E88BFB70 /* AggregratedReaction.swift in Sources */ = {isa = PBXBuildFile; fileRef = F15BE37BE2FB86E00C8D150A /* AggregratedReaction.swift */; };
 		719E7AAD1F8E68F68F30FECD /* Task.swift in Sources */ = {isa = PBXBuildFile; fileRef = A40C19719687984FD9478FBE /* Task.swift */; };
@@ -964,6 +965,7 @@
 		E6281B199D8A8F0892490C2E /* OnboardingCoordinator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OnboardingCoordinator.swift; sourceTree = "<group>"; };
 		E8294DB9E95C0C0630418466 /* ru */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ru; path = ru.lproj/Localizable.strings; sourceTree = "<group>"; };
 		E8CA187FE656EE5A3F6C7DE5 /* UIFont+AttributedStringBuilder.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "UIFont+AttributedStringBuilder.m"; sourceTree = "<group>"; };
+		E96ED747FF90332EA1333C22 /* RoomTimelineItemFixtures.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RoomTimelineItemFixtures.swift; sourceTree = "<group>"; };
 		E9D059BFE329BE09B6D96A9F /* ro */ = {isa = PBXFileReference; lastKnownFileType = text.plist.stringsdict; name = ro; path = ro.lproj/Localizable.stringsdict; sourceTree = "<group>"; };
 		EB3B237387B8288A5A938F1B /* UserAgentBuilderTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UserAgentBuilderTests.swift; sourceTree = "<group>"; };
 		EBE5502760CF6CA2D7201883 /* ja */ = {isa = PBXFileReference; lastKnownFileType = text.plist.stringsdict; name = ja; path = ja.lproj/Localizable.stringsdict; sourceTree = "<group>"; };
@@ -1295,6 +1297,14 @@
 			path = Helpers;
 			sourceTree = "<group>";
 		};
+		3EA31CC7012EA2A5653DAFC9 /* Fixtures */ = {
+			isa = PBXGroup;
+			children = (
+				E96ED747FF90332EA1333C22 /* RoomTimelineItemFixtures.swift */,
+			);
+			path = Fixtures;
+			sourceTree = "<group>";
+		};
 		3F38EAC92E2281990E65DAF2 /* OnboardingScreen */ = {
 			isa = PBXGroup;
 			children = (
@@ -2293,6 +2303,7 @@
 				66F2402D738694F98729A441 /* RoomTimelineProvider.swift */,
 				095AED4CF56DFF3EB7BB84C8 /* RoomTimelineProviderProtocol.swift */,
 				2D505843AB66822EB91F0DF0 /* TimelineItemProxy.swift */,
+				3EA31CC7012EA2A5653DAFC9 /* Fixtures */,
 				5A7A7D6D373D411C8C48B881 /* TimeLineItemContent */,
 				95BE1C7CB2C80344FF0BE724 /* TimelineItems */,
 			);
@@ -2973,6 +2984,7 @@
 				9B8DE1D424E37581C7D99CCC /* RoomTimelineControllerProtocol.swift in Sources */,
 				4E945AD6862C403F74E57755 /* RoomTimelineItemFactory.swift in Sources */,
 				13C77FDF17C4C6627CFFC205 /* RoomTimelineItemFactoryProtocol.swift in Sources */,
+				70558528EF68CAAEF09972D5 /* RoomTimelineItemFixtures.swift in Sources */,
 				C8E82786DE1B6A400DA9BA25 /* RoomTimelineItemProperties.swift in Sources */,
 				1AE4AEA0FA8DEF52671832E0 /* RoomTimelineItemProtocol.swift in Sources */,
 				9BD3A773186291560DF92B62 /* RoomTimelineProvider.swift in Sources */,

ElementX/Sources/Screens/RoomScreen/View/TimelineView.swift

@@ -26,7 +26,6 @@ struct TimelineView: UIViewControllerRepresentable {
                                                               timelineStyle: timelineStyle,
                                                               scrollToBottomButtonVisible: $viewModelContext.scrollToBottomButtonVisible,
                                                               scrollToBottomPublisher: viewModelContext.viewState.scrollToBottomPublisher)
-        viewModelContext.send(viewAction: .paginateBackwards)
         return tableViewController
     }
     
@@ -46,6 +45,10 @@ struct TimelineView: UIViewControllerRepresentable {
         
         init(viewModelContext: RoomScreenViewModel.Context) {
             context = viewModelContext
+            
+            if viewModelContext.viewState.items.isEmpty {
+                viewModelContext.send(viewAction: .paginateBackwards)
+            }
         }
         
         /// Updates the specified table view's properties from the current view state.

ElementX/Sources/Services/Timeline/Fixtures/RoomTimelineItemFixtures.swift

@@ -0,0 +1,222 @@
+//
+// Copyright 2022 New Vector Ltd
+//
+// 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
+//
+// http://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.
+//
+
+import Foundation
+
+enum RoomTimelineItemFixtures {
+    /// The default timeline items used in Xcode previews etc.
+    static var `default`: [RoomTimelineItemProtocol] = [
+        SeparatorRoomTimelineItem(id: UUID().uuidString,
+                                  text: "Yesterday"),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "That looks so good!",
+                             timestamp: "10:10 AM",
+                             inGroupState: .single,
+                             isOutgoing: false,
+                             isEditable: false,
+                             senderId: "",
+                             senderDisplayName: "Jacob",
+                             properties: RoomTimelineItemProperties(isEdited: true)),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "Let’s get lunch soon! New salad place opened up 🥗. When are y’all free? 🤗",
+                             timestamp: "10:11 AM",
+                             inGroupState: .beginning,
+                             isOutgoing: false,
+                             isEditable: false,
+                             senderId: "",
+                             senderDisplayName: "Helena",
+                             properties: RoomTimelineItemProperties(reactions: [
+                                 AggregatedReaction(key: "🙌", count: 1, isHighlighted: true)
+                             ])),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "I can be around on Wednesday. How about some 🌮 instead? Like https://www.tortilla.co.uk/",
+                             timestamp: "10:11 AM",
+                             inGroupState: .end,
+                             isOutgoing: false,
+                             isEditable: false,
+                             senderId: "",
+                             senderDisplayName: "Helena",
+                             properties: RoomTimelineItemProperties(reactions: [
+                                 AggregatedReaction(key: "🙏", count: 1, isHighlighted: false),
+                                 AggregatedReaction(key: "🙌", count: 2, isHighlighted: true)
+                             ])),
+        SeparatorRoomTimelineItem(id: UUID().uuidString,
+                                  text: "Today"),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "Wow, cool. Ok, lets go the usual place tomorrow?! Is that too soon?  Here’s the menu, let me know what you want it’s on me!",
+                             timestamp: "5 PM",
+                             inGroupState: .single,
+                             isOutgoing: false,
+                             isEditable: false,
+                             senderId: "",
+                             senderDisplayName: "Helena"),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "And John's speech was amazing!",
+                             timestamp: "5 PM",
+                             inGroupState: .beginning,
+                             isOutgoing: true,
+                             isEditable: true,
+                             senderId: "",
+                             senderDisplayName: "Bob"),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "New home office set up!",
+                             timestamp: "5 PM",
+                             inGroupState: .end,
+                             isOutgoing: true,
+                             isEditable: true,
+                             senderId: "",
+                             senderDisplayName: "Bob",
+                             properties: RoomTimelineItemProperties(reactions: [
+                                 AggregatedReaction(key: "🙏", count: 1, isHighlighted: false),
+                                 AggregatedReaction(key: "😁", count: 3, isHighlighted: false)
+                             ])),
+        TextRoomTimelineItem(id: UUID().uuidString,
+                             text: "",
+                             attributedComponents: [
+                                 AttributedStringBuilderComponent(attributedString: "Hol' up", isBlockquote: false),
+                                 AttributedStringBuilderComponent(attributedString: "New home office set up!", isBlockquote: true),
+                                 AttributedStringBuilderComponent(attributedString: "That's amazing! Congrats 🥳", isBlockquote: false)
+                             ],
+                             timestamp: "5 PM",
+                             inGroupState: .single,
+                             isOutgoing: false,
+                             isEditable: false,
+                             senderId: "",
+                             senderDisplayName: "Helena")
+    ]
+    
+    /// A small chunk of events, containing 2 text items.
+    static var smallChunk: [RoomTimelineItemProtocol] {
+        [TextRoomTimelineItem(text: "Hey there 👋",
+                              inGroupState: .beginning,
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "How are you?",
+                              inGroupState: .end,
+                              senderDisplayName: "Alice")]
+    }
+    
+    /// A chunk of events that contains a single text item.
+    static var singleMessageChunk: [RoomTimelineItemProtocol] {
+        [TextRoomTimelineItem(text: "Tap tap tap 🎙️. Is this thing on?",
+                              inGroupState: .single,
+                              senderDisplayName: "Helena")]
+    }
+    
+    /// A single text item.
+    static var incomingMessage: RoomTimelineItemProtocol {
+        TextRoomTimelineItem(text: "Hello, World!",
+                             inGroupState: .single,
+                             senderDisplayName: "Bob")
+    }
+    
+    /// A large chunk of events, containing 40 text items which should fill an iPad
+    /// with enough items so that it won't perform another back pagination.
+    static var largeChunk: [RoomTimelineItemProtocol] {
+        [TextRoomTimelineItem(text: "Bacon ipsum dolor amet commodo incididunt ribeye dolore cupidatat short ribs.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Labore ipsum jowl meatloaf adipisicing ham leberkas.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Tongue culpa dolor, short ribs doner cillum do rump id nulla mollit.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Capicola laborum aute porchetta, kevin ut ut bacon swine kielbasa beef rump ipsum.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Leberkas beef ad salami flank laborum ex veniam excepteur picanha occaecat burgdoggen.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Magna leberkas nostrud laboris, biltong in tongue nulla et id drumstick brisket.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Landjaeger adipisicing spare ribs sunt pig voluptate beef ribs venison ut meatloaf nulla beef sed.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Bacon chicken excepteur, filet mignon pastrami meatball ribeye sunt sausage.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Ham et dolore, nisi adipisicing kielbasa andouille ribeye enim chicken.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Ribeye prosciutto aliquip tail dolore.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Salami culpa exercitation ea non rump consectetur ipsum boudin irure jerky spare ribs duis leberkas pastrami.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Andouille shankle magna pig corned beef strip steak ex landjaeger sed chicken drumstick.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Deserunt ea esse quis bresaola, ham hock sirloin spare ribs porchetta dolore ham nisi est.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Consectetur nulla laboris, rump minim tempor turducken sunt tongue in.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Ea ut laboris eu spare ribs occaecat esse et shankle chicken.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Frankfurter brisket eu, landjaeger ea ham hamburger rump eiusmod pastrami cow.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Qui prosciutto sed, officia occaecat drumstick non veniam in elit chicken capicola buffalo beef ribs irure.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "In pork loin lorem, pariatur tail cupim voluptate chicken id eu pancetta esse pastrami.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Excepteur minim ea est, jerky sirloin frankfurter nisi dolor ball tip.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Shank corned beef velit chislic, pork chop enim in chuck in excepteur fatback minim.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Mollit minim ipsum in, in do doner ribeye cow jowl short loin sed.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Meatloaf est hamburger, spare ribs pork belly officia dolor.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Pancetta do aliqua picanha tempor.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Ad pig incididunt doner pork chop flank velit capicola aliqua.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Ullamco ex qui kevin meatball, leberkas hamburger venison.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Capicola et esse, fatback porchetta filet mignon ham nulla salami shank.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Boudin adipisicing pancetta chuck spare ribs beef ribs, in ut pork kevin.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Adipisicing pig short loin hamburger nisi exercitation landjaeger pancetta picanha ex cupim beef ribs.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Burgdoggen tri-tip eu elit consectetur, hamburger dolore commodo bacon capicola esse ex exercitation anim nostrud.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Id burgdoggen bresaola pork.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Pariatur meatloaf dolore tenderloin ea et proident strip steak velit nostrud pork loin laboris.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Pork chop cupim pastrami, prosciutto chislic kevin tempor eu ut deserunt ut occaecat consectetur non.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Aliquip kevin fugiat esse, adipisicing bresaola andouille biltong.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Andouille est picanha, beef ribs boudin exercitation flank venison ea tongue landjaeger meatloaf velit.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Boudin rump hamburger laborum adipisicing consectetur officia frankfurter shoulder quis biltong fugiat esse.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Ham hock culpa corned beef cupim pastrami swine in.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Boudin adipisicing pancetta chuck spare ribs beef ribs, in ut pork kevin.",
+                              senderDisplayName: "Bob"),
+         TextRoomTimelineItem(text: "Aliquip meatball incididunt fatback, pork belly in jowl tri-tip commodo spare ribs.",
+                              senderDisplayName: "Alice"),
+         TextRoomTimelineItem(text: "Excepteur rump tri-tip culpa in shankle esse ut.",
+                              senderDisplayName: "Helena"),
+         TextRoomTimelineItem(text: "Pork buffalo mollit culpa strip steak in leberkas flank cow.",
+                              senderDisplayName: "Alice")]
+    }
+}
+
+private extension TextRoomTimelineItem {
+    init(text: String, inGroupState: TimelineItemInGroupState = .single, senderDisplayName: String) {
+        self.init(id: UUID().uuidString,
+                  text: text,
+                  timestamp: "10:47 am",
+                  inGroupState: inGroupState,
+                  isOutgoing: senderDisplayName == "Alice",
+                  isEditable: false,
+                  senderId: "",
+                  senderDisplayName: senderDisplayName)
+    }
+}

ElementX/Sources/Services/Timeline/MockRoomTimelineController.swift

@@ -18,92 +18,54 @@ import Combine
 import Foundation
 
 class MockRoomTimelineController: RoomTimelineControllerProtocol {
+    /// An array of timeline item arrays that will be inserted in order for each back pagination request.
+    var backPaginationResponses: [[RoomTimelineItemProtocol]] = []
+    /// The time delay added to each back pagination request.
+    var backPaginationDelay: Duration = .milliseconds(500)
+    
+    /// An array of timeline items that will be appended in order when ``simulateIncomingItems()`` is called.
+    var incomingItems: [RoomTimelineItemProtocol] = []
+    /// The time delay between each incoming item.
+    var incomingDelay: Duration = .milliseconds(750)
+    
     let roomId = "MockRoomIdentifier"
     
     let callbacks = PassthroughSubject<RoomTimelineControllerCallback, Never>()
     
-    var timelineItems: [RoomTimelineItemProtocol] = [
+    var timelineItems: [RoomTimelineItemProtocol] = RoomTimelineItemFixtures.default
-        SeparatorRoomTimelineItem(id: UUID().uuidString,
+    
-                                  text: "Yesterday"),
+    func simulateIncomingItems() {
-        TextRoomTimelineItem(id: UUID().uuidString,
+        guard !incomingItems.isEmpty else { return }
-                             text: "That looks so good!",
+        
-                             timestamp: "10:10 AM",
+        let incomingItem = incomingItems.removeFirst()
-                             inGroupState: .single,
+        
-                             isOutgoing: false,
+        Task {
-                             isEditable: false,
+            try await Task.sleep(for: incomingDelay)
-                             senderId: "",
+            timelineItems.append(incomingItem)
-                             senderDisplayName: "Jacob",
+            callbacks.send(.updatedTimelineItems)
-                             properties: RoomTimelineItemProperties(isEdited: true)),
+            
-        TextRoomTimelineItem(id: UUID().uuidString,
+            if !self.incomingItems.isEmpty {
-                             text: "Let’s get lunch soon! New salad place opened up 🥗. When are y’all free? 🤗",
+                simulateIncomingItems()
-                             timestamp: "10:11 AM",
+            }
-                             inGroupState: .beginning,
+        }
-                             isOutgoing: false,
+    }
-                             isEditable: false,
-                             senderId: "",
-                             senderDisplayName: "Helena",
-                             properties: RoomTimelineItemProperties(reactions: [
-                                 AggregatedReaction(key: "🙌", count: 1, isHighlighted: true)
-                             ])),
-        TextRoomTimelineItem(id: UUID().uuidString,
-                             text: "I can be around on Wednesday. How about some 🌮 instead? Like https://www.tortilla.co.uk/",
-                             timestamp: "10:11 AM",
-                             inGroupState: .end,
-                             isOutgoing: false,
-                             isEditable: false,
-                             senderId: "",
-                             senderDisplayName: "Helena",
-                             properties: RoomTimelineItemProperties(reactions: [
-                                 AggregatedReaction(key: "🙏", count: 1, isHighlighted: false),
-                                 AggregatedReaction(key: "🙌", count: 2, isHighlighted: true)
-                             ])),
-        SeparatorRoomTimelineItem(id: UUID().uuidString,
-                                  text: "Today"),
-        TextRoomTimelineItem(id: UUID().uuidString,
-                             text: "Wow, cool. Ok, lets go the usual place tomorrow?! Is that too soon?  Here’s the menu, let me know what you want it’s on me!",
-                             timestamp: "5 PM",
-                             inGroupState: .single,
-                             isOutgoing: false,
-                             isEditable: false,
-                             senderId: "",
-                             senderDisplayName: "Helena"),
-        TextRoomTimelineItem(id: UUID().uuidString,
-                             text: "And John's speech was amazing!",
-                             timestamp: "5 PM",
-                             inGroupState: .beginning,
-                             isOutgoing: true,
-                             isEditable: true,
-                             senderId: "",
-                             senderDisplayName: "Bob"),
-        TextRoomTimelineItem(id: UUID().uuidString,
-                             text: "New home office set up!",
-                             timestamp: "5 PM",
-                             inGroupState: .end,
-                             isOutgoing: true,
-                             isEditable: true,
-                             senderId: "",
-                             senderDisplayName: "Bob",
-                             properties: RoomTimelineItemProperties(reactions: [
-                                 AggregatedReaction(key: "🙏", count: 1, isHighlighted: false),
-                                 AggregatedReaction(key: "😁", count: 3, isHighlighted: false)
-                             ])),
-        TextRoomTimelineItem(id: UUID().uuidString,
-                             text: "",
-                             attributedComponents: [
-                                 AttributedStringBuilderComponent(attributedString: "Hol' up", isBlockquote: false),
-                                 AttributedStringBuilderComponent(attributedString: "New home office set up!", isBlockquote: true),
-                                 AttributedStringBuilderComponent(attributedString: "That's amazing! Congrats 🥳", isBlockquote: false)
-                             ],
-                             timestamp: "5 PM",
-                             inGroupState: .single,
-                             isOutgoing: false,
-                             isEditable: false,
-                             senderId: "",
-                             senderDisplayName: "Helena")
-    ]
     
     func paginateBackwards(_ count: UInt) async -> Result<Void, RoomTimelineControllerError> {
-        .failure(.generic)
+        callbacks.send(.startedBackPaginating)
+        
+        guard !backPaginationResponses.isEmpty else {
+            callbacks.send(.finishedBackPaginating)
+            return .failure(.generic)
+        }
+        
+        let newItems = backPaginationResponses.removeFirst()
+        
+        try? await Task.sleep(for: backPaginationDelay)
+        timelineItems.insert(contentsOf: newItems, at: 0)
+        callbacks.send(.updatedTimelineItems)
+        callbacks.send(.finishedBackPaginating)
+        
+        return .success(())
     }
     
     func processItemAppearance(_ itemId: String) async { }

ElementX/Sources/UITests/UITestScreenIdentifier.swift

@@ -32,6 +32,9 @@ enum UITestScreenIdentifier: String {
     case onboarding
     case roomPlainNoAvatar
     case roomEncryptedWithAvatar
+    case roomSmallTimeline
+    case roomSmallTimelineIncomingAndSmallPagination
+    case roomSmallTimelineLargePagination
     case sessionVerification
 }
 

ElementX/Sources/UITests/UITestsAppCoordinator.swift

@@ -23,6 +23,7 @@ class UITestsAppCoordinator: AppCoordinatorProtocol {
     let notificationManager: NotificationManagerProtocol? = nil
     
     init() {
+        UIView.setAnimationsEnabled(false)
         navigationStackCoordinator = NavigationStackCoordinator()
         
         ServiceLocator.shared.register(userNotificationController: MockUserNotificationController())
@@ -132,6 +133,40 @@ class MockScreen: Identifiable {
                                                              roomAvatarUrl: "mock_url",
                                                              emojiProvider: EmojiProvider())
             return RoomScreenCoordinator(parameters: parameters)
+        case .roomSmallTimeline:
+            let timelineController = MockRoomTimelineController()
+            timelineController.timelineItems = RoomTimelineItemFixtures.smallChunk
+            let parameters = RoomScreenCoordinatorParameters(navigationStackCoordinator: navigationStackCoordinator,
+                                                             timelineController: timelineController,
+                                                             mediaProvider: MockMediaProvider(),
+                                                             roomName: "New room",
+                                                             roomAvatarUrl: "mock_url",
+                                                             emojiProvider: EmojiProvider())
+            return RoomScreenCoordinator(parameters: parameters)
+        case .roomSmallTimelineIncomingAndSmallPagination:
+            let timelineController = MockRoomTimelineController()
+            timelineController.timelineItems = RoomTimelineItemFixtures.smallChunk
+            timelineController.backPaginationResponses = [RoomTimelineItemFixtures.singleMessageChunk]
+            timelineController.incomingItems = [RoomTimelineItemFixtures.incomingMessage]
+            timelineController.simulateIncomingItems()
+            let parameters = RoomScreenCoordinatorParameters(navigationStackCoordinator: navigationStackCoordinator,
+                                                             timelineController: timelineController,
+                                                             mediaProvider: MockMediaProvider(),
+                                                             roomName: "Small timeline",
+                                                             roomAvatarUrl: "mock_url",
+                                                             emojiProvider: EmojiProvider())
+            return RoomScreenCoordinator(parameters: parameters)
+        case .roomSmallTimelineLargePagination:
+            let timelineController = MockRoomTimelineController()
+            timelineController.timelineItems = RoomTimelineItemFixtures.smallChunk
+            timelineController.backPaginationResponses = [RoomTimelineItemFixtures.largeChunk]
+            let parameters = RoomScreenCoordinatorParameters(navigationStackCoordinator: navigationStackCoordinator,
+                                                             timelineController: timelineController,
+                                                             mediaProvider: MockMediaProvider(),
+                                                             roomName: "Small timeline, paginating",
+                                                             roomAvatarUrl: "mock_url",
+                                                             emojiProvider: EmojiProvider())
+            return RoomScreenCoordinator(parameters: parameters)
         case .sessionVerification:
             let parameters = SessionVerificationCoordinatorParameters(sessionVerificationControllerProxy: MockSessionVerificationControllerProxy())
             return SessionVerificationCoordinator(parameters: parameters)

UITests/Sources/Application.swift

@@ -33,7 +33,7 @@ extension XCUIApplication {
         let lastLabel = staticTexts["lastItem"]
         
         while !button.isHittable, !lastLabel.isHittable {
-            tables.firstMatch.swipeUp()
+            swipeUp()
         }
         
         button.tap()

UITests/Sources/RoomScreenUITests.swift

@@ -38,4 +38,28 @@ class RoomScreenUITests: XCTestCase {
 
         app.assertScreenshot(.roomEncryptedWithAvatar)
     }
+    
+    func testSmallTimelineLayout() {
+        let app = Application.launch()
+        app.goToScreenWithIdentifier(.roomSmallTimeline)
+        
+        // The messages should be bottom aligned.
+        app.assertScreenshot(.roomSmallTimeline)
+    }
+    
+    func testSmallTimelineWithIncomingAndPagination() {
+        let app = Application.launch()
+        app.goToScreenWithIdentifier(.roomSmallTimelineIncomingAndSmallPagination)
+        
+        // Wait for both the incoming message and the pagination chunk.
+        XCTAssert(app.staticTexts["Bob"].waitForExistence(timeout: 2))
+        XCTAssert(app.staticTexts["Helena"].waitForExistence(timeout: 2))
+
+        // The messages should still be bottom aligned after the new items are added.
+        app.assertScreenshot(.roomSmallTimelineIncomingAndSmallPagination)
+    }
+    
+    func testSmallTimelineWithLargePagination() {
+        // To be implemented
+    }
 }

UITests/Sources/__Snapshots__/Application/de-DE-iPad-9th-generation.roomSmallTimeline.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:96d580e92e1618c729240a00439801feccbfadf6bd7e00119a4df5b3724e1c82
+size 92567

UITests/Sources/__Snapshots__/Application/de-DE-iPad-9th-generation.roomSmallTimelineIncomingAndSmallPagination.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:925c9edf55718ec2e1195fbe8a6e313f435eee075c703c74a487ca0425a60f2f
+size 133380

UITests/Sources/__Snapshots__/Application/de-DE-iPhone-14.roomSmallTimeline.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3295b6e8348a37998c95f72285ae0bfc5651ec3166a376c327f482a0baa1e93d
+size 114678

UITests/Sources/__Snapshots__/Application/de-DE-iPhone-14.roomSmallTimelineIncomingAndSmallPagination.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:015eb7e93e193d635194bb6d0d67a3a8751180598fc63762ada0f94be11099e9
+size 212903

UITests/Sources/__Snapshots__/Application/en-GB-iPad-9th-generation.roomSmallTimeline.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:12af6767660c17c4eaebdb951da4e61ac1cc365ba950e237fe8f08d4707f39a5
+size 92342

UITests/Sources/__Snapshots__/Application/en-GB-iPad-9th-generation.roomSmallTimelineIncomingAndSmallPagination.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:087309a5c640fe574e3f80e9e8cbccef71bced0d49016a27c963d7bff07e24d1
+size 133159

UITests/Sources/__Snapshots__/Application/en-GB-iPhone-14.roomSmallTimeline.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a365ef80c8bce284dfddd840433afe9fa6b3d7eee8521da98e065777a6819530
+size 114689

UITests/Sources/__Snapshots__/Application/en-GB-iPhone-14.roomSmallTimelineIncomingAndSmallPagination.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:31267576b8c4c8d038b3f5dde9e3f6c1f06c00b72cea3e5e9d02765e231fa682
+size 212873

UITests/Sources/__Snapshots__/Application/fr-FR-iPad-9th-generation.roomSmallTimeline.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:12af6767660c17c4eaebdb951da4e61ac1cc365ba950e237fe8f08d4707f39a5
+size 92342

UITests/Sources/__Snapshots__/Application/fr-FR-iPad-9th-generation.roomSmallTimelineIncomingAndSmallPagination.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:087309a5c640fe574e3f80e9e8cbccef71bced0d49016a27c963d7bff07e24d1
+size 133159

UITests/Sources/__Snapshots__/Application/fr-FR-iPhone-14.roomSmallTimeline.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:180aae2e7f67beb59cfee31788efaf7f0a6b4fef910956ba1db1ed22edbfdc7f
+size 114685

UITests/Sources/__Snapshots__/Application/fr-FR-iPhone-14.roomSmallTimelineIncomingAndSmallPagination.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:31267576b8c4c8d038b3f5dde9e3f6c1f06c00b72cea3e5e9d02765e231fa682
+size 212873

changelog.d/352.change

@@ -0,0 +1 @@
+Timeline: Add a couple of basic tests to make sure the timeline is bottom aligned.