msglist: Distinguish isBot: true message senders with a bot marker

Fixes: zulip#156

Author: sm-sayedi

lib/widgets/message_list.dart

@@ -896,7 +896,10 @@ class MessageWithPossibleSender extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final store = PerAccountStoreWidget.of(context);
+
     final message = item.message;
+    final sender = store.users[message.senderId];
 
     Widget? senderRow;
     if (item.showSender) {
@@ -926,6 +929,14 @@ class MessageWithPossibleSender extends StatelessWidget {
                       ).merge(weightVariableTextStyle(context, wght: 600,
                                 wghtIfPlatformRequestsBold: 900)),
                       overflow: TextOverflow.ellipsis)),
+                  if (sender?.isBot ?? false) ...[
+                    const SizedBox(width: 5),
+                    const Icon(
+                      ZulipIcons.bot,
+                      size: 15,
+                      color: Color.fromARGB(255, 159, 173, 173),
+                    ),
+                  ],
                 ]))),
           const SizedBox(width: 4),
           Text(time,

test/example_data.dart

@@ -75,6 +75,7 @@ User user({
   String? email,
   String? fullName,
   bool? isActive,
+  bool? isBot,
   String? avatarUrl,
   Map<int, ProfileFieldUserData>? profileData,
 }) {
@@ -89,7 +90,7 @@ User user({
     isAdmin: false,
     isGuest: false,
     isBillingAdmin: false,
-    isBot: false,
+    isBot: isBot ?? false,
     botType: null,
     botOwnerId: null,
     role: UserRole.member,

test/widgets/message_list_test.dart

@@ -43,6 +43,7 @@ void main() {
     int? messageCount,
     List<Message>? messages,
     List<ZulipStream>? streams,
+    List<User>? users,
     List<Subscription>? subscriptions,
     UnreadMessagesSnapshot? unreadMsgs,
   }) async {
@@ -55,6 +56,7 @@ void main() {
 
     // prepare message list data
     store.addUser(eg.selfUser);
+    store.addUsers(users ?? []);
     assert((messageCount == null) != (messages == null));
     messages ??= List.generate(messageCount!, (index) {
       return eg.streamMessage(sender: eg.selfUser);
@@ -479,6 +481,49 @@ void main() {
 
       debugNetworkImageHttpClientProvider = null;
     });
+
+    testWidgets('Bot user is distinguished by showing an icon', (tester) async {
+      // When using this function, provide only one bot user
+      // to [PerAccountStore] through [setupMessageListPage] function.
+      void checkUser(User user, {required bool isBot}) {
+        final nameFinder = find.text(user.fullName);
+        final botFinder = find.byIcon(ZulipIcons.bot);
+
+        check(nameFinder.evaluate().singleOrNull).isNotNull();
+        check(botFinder.evaluate().singleOrNull).isNotNull();
+
+        final userFinder = find.ancestor(
+          of: nameFinder,
+          matching: find.ancestor(
+            of: botFinder,
+            matching: find.byType(Row),
+          ));
+
+        isBot
+          ? check(userFinder.evaluate()).isNotEmpty()
+          : check(userFinder.evaluate()).isEmpty();
+      }
+
+      prepareBoringImageHttpClient();
+
+      final users = [
+        eg.user(fullName: 'User 1', isBot: true),
+        eg.user(fullName: 'User 2', isBot: false),
+        eg.user(fullName: 'User 3', isBot: false),
+      ];
+
+      await setupMessageListPage(
+        tester,
+        messages: users.map((user) => eg.streamMessage(sender: user)).toList(),
+        users: users,
+      );
+
+      checkUser(users[0], isBot: true);
+      checkUser(users[1], isBot: false);
+      checkUser(users[2], isBot: false);
+
+      debugNetworkImageHttpClientProvider = null;
+    });
   });
 
   group('Starred messages', () {