TF-3551 E2E Mailbox scroll and back to top

integration_test/robots/thread_robot.dart

@@ -4,6 +4,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:tmail_ui_user/features/base/widget/compose_floating_button.dart';
 import 'package:tmail_ui_user/features/thread/presentation/thread_view.dart';
 import 'package:tmail_ui_user/features/thread/presentation/widgets/email_tile_builder.dart';
+import 'package:tmail_ui_user/features/thread/presentation/widgets/scroll_to_top_button_widget.dart';
 import 'package:tmail_ui_user/main/localizations/app_localizations.dart';
 
 import '../base/core_robot.dart';
@@ -40,4 +41,14 @@ class ThreadRobot extends CoreRobot {
   Future<void> tapDeleteAllButtonOnEmptyTrashConfirmDialog(
     AppLocalizations appLocalizations,
   ) => $(appLocalizations.delete_all).tap();
+
+  Future<void> scrollToEmailWithSubject(String subject) async {
+    await $.scrollUntilVisible(finder: $(subject), delta: 300);
+    await $.pumpAndSettle();
+  }
+
+  Future<void> scrollToTop() async {
+    await $(ScrollToTopButtonWidget).$(InkWell).tap();
+    await $.pumpAndSettle();
+  }
 }

integration_test/scenarios/mailbox/scroll_list_email_in_mailbox_and_back_to_top_scenario.dart

@@ -0,0 +1,51 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:tmail_ui_user/features/thread/presentation/widgets/scroll_to_top_button_widget.dart';
+
+import '../../base/base_test_scenario.dart';
+import '../../models/provisioning_email.dart';
+import '../../robots/thread_robot.dart';
+
+class ScrollListEmailInMailboxAndBackToTopScenario extends BaseTestScenario {
+  const ScrollListEmailInMailboxAndBackToTopScenario(super.$);
+
+  String _getSubjectWithIndex(int emailIndex) => 'scroll email subject $emailIndex';
+
+  @override
+  Future<void> runTestLogic() async {
+    const email = String.fromEnvironment('BASIC_AUTH_EMAIL');
+    const totalEmails = 15;
+    const bottomEmailSubject = 'scroll email subject bottom';
+
+    final threadRobot = ThreadRobot($);
+
+    await provisionEmail([ProvisioningEmail(
+      toEmail: email,
+      subject: bottomEmailSubject,
+      content: '',
+    )]);
+    await $.pumpAndSettle(duration: const Duration(seconds: 2));
+    await provisionEmail(List.generate(
+      totalEmails,
+      (index) => ProvisioningEmail(
+        toEmail: email,
+        subject: _getSubjectWithIndex(index),
+        content: '$index',
+      ),
+    ));
+    await $.pumpAndSettle(duration: const Duration(seconds: 2));
+
+    await threadRobot.scrollToEmailWithSubject(bottomEmailSubject);
+    await _expectScrollToTopButtonVisible();
+
+    await threadRobot.scrollToTop();
+    await _expectScrollToTopButtonInvisible();
+  }
+  
+  _expectScrollToTopButtonVisible() {
+    expect($(ScrollToTopButtonWidget), findsOneWidget);
+  }
+
+  Future<void> _expectScrollToTopButtonInvisible() async {
+    expect($(ScrollToTopButtonWidget).visible, false);
+  }
+}

integration_test/tests/mailbox/scroll_list_email_in_mailbox_and_back_to_top_test.dart

@@ -0,0 +1,10 @@
+import '../../base/test_base.dart';
+import '../../scenarios/mailbox/scroll_list_email_in_mailbox_and_back_to_top_scenario.dart';
+
+void main() {
+  TestBase().runPatrolTest(
+    description: 'Should see back to top button when scroll list email in mailbox to bottom '
+      'and not see back to top button when scroll list email to top',
+    scenarioBuilder: ($) => ScrollListEmailInMailboxAndBackToTopScenario($),
+  );
+}