example_data [nfc]: Move {newest,older}Result

Shared by a few tests, they fit better in example_data.

Signed-off-by: Zixuan James Li <[email protected]>

integration_test/unreadmarker_test.dart

@@ -9,7 +9,6 @@ import 'package:zulip/widgets/message_list.dart';
 import '../test/api/fake_api.dart';
 import '../test/example_data.dart' as eg;
 import '../test/model/binding.dart';
-import '../test/model/message_list_test.dart';
 import '../test/widgets/test_app.dart';
 
 void main() {
@@ -29,7 +28,7 @@ void main() {
     final messages = List.generate(messageCount,
       (i) => eg.streamMessage(flags: [MessageFlag.read]));
     connection.prepare(json:
-      newestResult(foundOldest: true, messages: messages).toJson());
+      eg.newestResult(foundOldest: true, messages: messages).toJson());
 
     await tester.pumpWidget(TestZulipApp(accountId: eg.selfAccount.id,
       child: const MessageListPage(initNarrow: CombinedFeedNarrow())));

test/example_data.dart

@@ -5,6 +5,7 @@ import 'package:zulip/api/model/events.dart';
 import 'package:zulip/api/model/initial_snapshot.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/api/model/submessage.dart';
+import 'package:zulip/api/route/messages.dart';
 import 'package:zulip/api/route/realm.dart';
 import 'package:zulip/api/route/channels.dart';
 import 'package:zulip/model/narrow.dart';
@@ -451,6 +452,43 @@ DmMessage dmMessage({
   }) as Map<String, dynamic>);
 }
 
+/// A GetMessagesResult the server might return on an `anchor=newest` request.
+GetMessagesResult newestResult({
+  required bool foundOldest,
+  bool historyLimited = false,
+  required List<Message> messages,
+}) {
+  return GetMessagesResult(
+    // These anchor, foundAnchor, and foundNewest values are what the server
+    // appears to always return when the request had `anchor=newest`.
+    anchor: 10000000000000000, // that's 16 zeros
+    foundAnchor: false,
+    foundNewest: true,
+
+    foundOldest: foundOldest,
+    historyLimited: historyLimited,
+    messages: messages,
+  );
+}
+
+/// A GetMessagesResult the server might return when we request older messages.
+GetMessagesResult olderResult({
+  required int anchor,
+  bool foundAnchor = false, // the value if the server understood includeAnchor false
+  required bool foundOldest,
+  bool historyLimited = false,
+  required List<Message> messages,
+}) {
+  return GetMessagesResult(
+    anchor: anchor,
+    foundAnchor: foundAnchor,
+    foundNewest: false, // empirically always this, even when anchor happens to be latest
+    foundOldest: foundOldest,
+    historyLimited: historyLimited,
+    messages: messages,
+  );
+}
+
 PollWidgetData pollWidgetData({
   required String question,
   required List<String> options,