test(ensemble): cover Page header listeners and ListViewCore scroll rebind

modules/ensemble/lib/framework/view/page.dart

@@ -26,6 +26,7 @@ import 'package:ensemble/widget/helpers/controllers.dart';
 import 'package:ensemble/widget/helpers/unfocus.dart';
 import 'package:ensemble/framework/bindings.dart';
 import 'package:flutter/material.dart';
+import 'package:meta/meta.dart';
 
 class SinglePageController extends WidgetController {
   TextStyleComposite? _textStyle;
@@ -1144,6 +1145,22 @@ class PageState extends State<Page>
     });
   }
 
+  @visibleForTesting
+  bool get isTitleBarHeightPollTimerActive =>
+      _titleBarHeightPollTimer?.isActive ?? false;
+
+  @visibleForTesting
+  bool get isHeaderVisibilityPollTimerActive =>
+      _headerVisibilityPollTimer?.isActive ?? false;
+
+  @visibleForTesting
+  bool get hasTitleBarHeightStorageSubscription =>
+      _titleBarHeightStorageSubscription != null;
+
+  @visibleForTesting
+  bool get hasHeaderVisibilityStorageSubscription =>
+      _headerVisibilityStorageSubscription != null;
+
   @override
   void dispose() {
     _titleBarHeightStorageSubscription?.cancel();

modules/ensemble/test/widget/list_view_test.dart

@@ -74,6 +74,47 @@ void main() {
     );
   });
 
+  testWidgets('ListViewCore rebinds when external scroll controller changes',
+      (tester) async {
+    final controllerA = ScrollController();
+    final controllerB = ScrollController();
+    final widget = listViewWithChild();
+    widget.setProperty('controller', controllerA);
+
+    await tester.pumpWidget(TestUtils.wrapTestWidgetWithScope(
+      SizedBox(height: 400, width: 400, child: widget),
+    ));
+    await tester.pump();
+
+    Scrollable scrollable = tester.widget<Scrollable>(
+      find.descendant(
+        of: find.byType(ensemble.ListView),
+        matching: find.byType(Scrollable),
+      ).first,
+    );
+    expect(scrollable.controller, same(controllerA));
+
+    widget.setProperty('controller', controllerB);
+    await tester.pumpWidget(TestUtils.wrapTestWidgetWithScope(
+      SizedBox(height: 400, width: 400, child: widget),
+    ));
+    await tester.pump();
+
+    scrollable = tester.widget<Scrollable>(
+      find.descendant(
+        of: find.byType(ensemble.ListView),
+        matching: find.byType(Scrollable),
+      ).first,
+    );
+    expect(scrollable.controller, same(controllerB));
+
+    await tester.pumpWidget(
+        TestUtils.wrapTestWidgetWithScope(const SizedBox.shrink()));
+    await tester.pump();
+    controllerA.dispose();
+    controllerB.dispose();
+  });
+
   testWidgets(
       'restores ListView scroll controller when leaving draggable footer scope',
       (tester) async {

modules/ensemble/test/widget/page_header_storage_listeners_test.dart

@@ -0,0 +1,106 @@
+import 'package:ensemble/framework/data_context.dart';
+import 'package:ensemble/framework/view/page.dart' as ensemble_page;
+import 'package:ensemble/page_model.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:get_storage/get_storage.dart';
+import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+import 'package:yaml/yaml.dart';
+
+class _FakePathProvider extends Fake
+    with MockPlatformInterfaceMixin
+    implements PathProviderPlatform {
+  @override
+  Future<String?> getApplicationDocumentsPath() async => '/tmp';
+}
+
+SinglePageModel _pageModelWithHeaderStorageListeners() {
+  return PageModel.fromYaml(YamlMap.wrap({
+    'View': {
+      'header': {
+        'titleText': 'Test Page',
+        'styles': {
+          'listenTitleBarHeightStorage': true,
+          'titleBarHeight': r'${ensemble.storage.get("headerHeight")}',
+          'collapsibleHeader': {
+            'enabled': true,
+            'visible': r'${ensemble.storage.get("headerVisible")}',
+          },
+        },
+      },
+      'body': {
+        'Text': {'text': 'Body'},
+      },
+    },
+  })) as SinglePageModel;
+}
+
+Widget _wrapPage(SinglePageModel pageModel) {
+  return MaterialApp(
+    home: Builder(
+      builder: (context) => ensemble_page.Page(
+        dataContext: DataContext(buildContext: context),
+        pageModel: pageModel,
+        onRendered: () {},
+      ),
+    ),
+  );
+}
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  PathProviderPlatform.instance = _FakePathProvider();
+
+  setUpAll(() async {
+    await GetStorage.init();
+  });
+
+  setUp(() async {
+    await GetStorage().write('headerHeight', 56);
+    await GetStorage().write('headerVisible', true);
+  });
+
+  tearDown(() async {
+    await GetStorage().erase();
+  });
+
+  testWidgets(
+    'registers one title bar storage listener instead of duplicate subscriptions',
+    (tester) async {
+      await tester.pumpWidget(_wrapPage(_pageModelWithHeaderStorageListeners()));
+      await tester.pump();
+
+      final state =
+          tester.state<ensemble_page.PageState>(find.byType(ensemble_page.Page));
+      expect(state.hasTitleBarHeightStorageSubscription, isTrue);
+      expect(state.hasHeaderVisibilityStorageSubscription, isTrue);
+      expect(state.isTitleBarHeightPollTimerActive, isTrue);
+      expect(state.isHeaderVisibilityPollTimerActive, isTrue);
+
+      await tester.pumpWidget(const MaterialApp(home: SizedBox.shrink()));
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 150));
+      expect(tester.takeException(), isNull);
+    },
+  );
+
+  testWidgets('cancels header poll timers and subscriptions on dispose',
+      (tester) async {
+    await tester.pumpWidget(_wrapPage(_pageModelWithHeaderStorageListeners()));
+    await tester.pump();
+
+    final state =
+        tester.state<ensemble_page.PageState>(find.byType(ensemble_page.Page));
+    expect(state.isTitleBarHeightPollTimerActive, isTrue);
+    expect(state.isHeaderVisibilityPollTimerActive, isTrue);
+
+    await tester.pumpWidget(const MaterialApp(home: SizedBox.shrink()));
+    await tester.pump();
+
+    // Timers were cancelled synchronously in dispose; advancing time must not
+    // trigger setState on a disposed PageState.
+    await tester.pump(const Duration(milliseconds: 500));
+    expect(tester.takeException(), isNull);
+  });
+}