Convert some more widget tests to NNBD (#68129)

packages/flutter/test/widgets/restoration_scope_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/widgets.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -74,7 +72,7 @@ void main() {
       manager.doSerialization();
 
       final BucketSpyState state = tester.state(find.byType(BucketSpy));
-      expect(state.bucket.restorationId, id);
+      expect(state.bucket!.restorationId, id);
       expect(rawData[childrenMapKey].containsKey(id), isTrue);
     });
 
@@ -94,8 +92,8 @@ void main() {
       manager.doSerialization();
 
       final BucketSpyState state = tester.state(find.byType(BucketSpy));
-      expect(state.bucket.restorationId, 'child1');
-      expect(state.bucket.read<int>('foo'), 22);
+      expect(state.bucket!.restorationId, 'child1');
+      expect(state.bucket!.read<int>('foo'), 22);
     });
 
     testWidgets('renames existing bucket when new ID is provided', (WidgetTester tester) async {
@@ -115,9 +113,9 @@ void main() {
 
       // Claimed existing bucket with data.
       final BucketSpyState state = tester.state(find.byType(BucketSpy));
-      expect(state.bucket.restorationId, 'child1');
-      expect(state.bucket.read<int>('foo'), 22);
-      final RestorationBucket bucket = state.bucket;
+      expect(state.bucket!.restorationId, 'child1');
+      expect(state.bucket!.read<int>('foo'), 22);
+      final RestorationBucket bucket = state.bucket!;
 
       // Rename the existing bucket.
       await tester.pumpWidget(
@@ -131,8 +129,8 @@ void main() {
       );
       manager.doSerialization();
 
-      expect(state.bucket.restorationId, 'something else');
-      expect(state.bucket.read<int>('foo'), 22);
+      expect(state.bucket!.restorationId, 'something else');
+      expect(state.bucket!.read<int>('foo'), 22);
       expect(state.bucket, same(bucket));
     });
 
@@ -193,7 +191,7 @@ void main() {
       );
       manager.doSerialization();
       expect(state.bucket, isNotNull);
-      expect(state.bucket.restorationId, 'foo');
+      expect(state.bucket!.restorationId, 'foo');
 
       // Change id back to null.
       await tester.pumpWidget(
@@ -237,7 +235,7 @@ void main() {
       );
       manager.doSerialization();
       expect(state.bucket, isNotNull);
-      expect(state.bucket.restorationId, 'foo');
+      expect(state.bucket!.restorationId, 'foo');
 
       // Move out of scope again.
       await tester.pumpWidget(
@@ -288,11 +286,11 @@ void main() {
       );
       manager.doSerialization();
       final BucketSpyState state = tester.state(find.byType(BucketSpy));
-      expect(state.bucket.restorationId, 'moving-child');
+      expect(state.bucket!.restorationId, 'moving-child');
       expect(rawData[childrenMapKey]['fixed'][childrenMapKey].containsKey('moving-child'), isTrue);
-      final RestorationBucket bucket = state.bucket;
+      final RestorationBucket bucket = state.bucket!;
 
-      state.bucket.write('value', 11);
+      state.bucket!.write('value', 11);
       manager.doSerialization();
 
       // Move scope.
@@ -316,9 +314,9 @@ void main() {
         ),
       );
       manager.doSerialization();
-      expect(state.bucket.restorationId, 'moving-child');
+      expect(state.bucket!.restorationId, 'moving-child');
       expect(state.bucket, same(bucket));
-      expect(state.bucket.read<int>('value'), 11);
+      expect(state.bucket!.read<int>('value'), 11);
 
       expect(rawData[childrenMapKey]['fixed'], isEmpty);
       expect(rawData[childrenMapKey].containsKey('moving-child'), isTrue);

packages/flutter/test/widgets/restoration_scopes_moving_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
@@ -123,13 +121,13 @@ class TestWidgetWithCounterChildState extends State<TestWidgetWithCounterChild>
   int toggleCount = 0;
 
   @override
-  void didToggleBucket(RestorationBucket oldBucket) {
+  void didToggleBucket(RestorationBucket? oldBucket) {
     super.didToggleBucket(oldBucket);
     toggleCount++;
   }
 
   @override
-  void restoreState(RestorationBucket oldBucket, bool initialRestore) {
+  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
     registerForRestoration(childRestorationEnabled, 'childRestorationEnabled');
   }
 
@@ -163,7 +161,7 @@ class TestWidgetWithCounterChildState extends State<TestWidgetWithCounterChild>
 class Counter extends StatefulWidget {
   const Counter({this.restorationId});
 
-  final String restorationId;
+  final String? restorationId;
 
   @override
   State<Counter> createState() => CounterState();
@@ -173,10 +171,10 @@ class CounterState extends State<Counter> with RestorationMixin {
   final RestorableInt count = RestorableInt(0);
 
   @override
-  String get restorationId => widget.restorationId;
+  String? get restorationId => widget.restorationId;
 
   @override
-  void restoreState(RestorationBucket oldBucket, bool initialRestore) {
+  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
     registerForRestoration(count, 'counter');
   }
 
@@ -202,20 +200,20 @@ class CounterState extends State<Counter> with RestorationMixin {
 }
 
 class TestWidget extends StatefulWidget {
-  const TestWidget({@required this.restorationId});
+  const TestWidget({required this.restorationId});
 
-  final String restorationId;
+  final String? restorationId;
 
   @override
   State<TestWidget> createState() => TestWidgetState();
 }
 
 class TestWidgetState extends State<TestWidget> with RestorationMixin {
-  List<RestorationBucket> buckets = <RestorationBucket>[];
+  List<RestorationBucket?> buckets = <RestorationBucket>[];
   List<bool> flags = <bool>[];
 
   @override
-  void restoreState(RestorationBucket oldBucket, bool initialRestore) {
+  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
     buckets.add(oldBucket);
     flags.add(initialRestore);
   }
@@ -223,13 +221,13 @@ class TestWidgetState extends State<TestWidget> with RestorationMixin {
   int toggleCount = 0;
 
   @override
-  void didToggleBucket(RestorationBucket oldBucket) {
+  void didToggleBucket(RestorationBucket? oldBucket) {
     super.didToggleBucket(oldBucket);
     toggleCount++;
   }
 
   @override
-  String get restorationId => widget.restorationId;
+  String? get restorationId => widget.restorationId;
 
   @override
   Widget build(BuildContext context) {

packages/flutter/test/widgets/root_restoration_scope_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 
 import 'package:flutter/foundation.dart';
@@ -44,7 +42,7 @@ void main() {
 
     expect(binding.restorationManager.rootBucketAccessed, 0);
     final BucketSpyState state = tester.state(find.byType(BucketSpy));
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
     expect(rawData[childrenMapKey].containsKey('root-child'), isTrue);
 
     expect(find.text('Hello'), findsOneWidget);
@@ -82,7 +80,7 @@ void main() {
     expect(binding.firstFrameIsDeferred, isFalse);
 
     final BucketSpyState state = tester.state(find.byType(BucketSpy));
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
     expect(rawData[childrenMapKey].containsKey('root-child'), isTrue);
   });
 
@@ -108,7 +106,7 @@ void main() {
     expect(binding.firstFrameIsDeferred, isFalse);
 
     final BucketSpyState state = tester.state(find.byType(BucketSpy));
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
     expect(rawData[childrenMapKey].containsKey('root-child'), isTrue);
   });
 
@@ -158,7 +156,7 @@ void main() {
 
     expect(binding.restorationManager.rootBucketAccessed, 1);
     expect(find.text('Hello'), findsOneWidget);
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
 
     // Change ID back to null.
     await tester.pumpWidget(
@@ -203,7 +201,7 @@ void main() {
     expect(binding.restorationManager.rootBucketAccessed, 0);
     expect(find.text('Hello'), findsOneWidget);
     final BucketSpyState state = tester.state(find.byType(BucketSpy));
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
     expect(inScopeRawData[childrenMapKey].containsKey('root-child'), isTrue);
 
     // Move out of scope.
@@ -232,7 +230,7 @@ void main() {
 
     expect(binding.restorationManager.rootBucketAccessed, 1);
     expect(find.text('Hello'), findsOneWidget);
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
     expect(outOfScopeRawData[childrenMapKey].containsKey('root-child'), isTrue);
     expect(inScopeRawData, isEmpty);
 
@@ -255,7 +253,7 @@ void main() {
 
     expect(binding.restorationManager.rootBucketAccessed, 1);
     expect(find.text('Hello'), findsOneWidget);
-    expect(state.bucket.restorationId, 'root-child');
+    expect(state.bucket!.restorationId, 'root-child');
     expect(outOfScopeRawData, isEmpty);
     expect(inScopeRawData[childrenMapKey].containsKey('root-child'), isTrue);
   });
@@ -280,9 +278,9 @@ void main() {
     expect(binding.restorationManager.rootBucketAccessed, 1);
     expect(find.text('Hello'), findsOneWidget);
     final BucketSpyState state = tester.state(find.byType(BucketSpy));
-    state.bucket.write('foo', 42);
+    state.bucket!.write('foo', 42);
     expect(firstRawData[childrenMapKey]['root-child'][valuesMapKey]['foo'], 42);
-    final RestorationBucket firstBucket = state.bucket;
+    final RestorationBucket firstBucket = state.bucket!;
 
     // Replace with new root.
     final Map<String, dynamic> secondRawData = <String, dynamic>{
@@ -300,7 +298,7 @@ void main() {
     firstRoot.dispose();
 
     expect(state.bucket, isNot(same(firstBucket)));
-    expect(state.bucket.read<int>('foo'), 22);
+    expect(state.bucket!.read<int>('foo'), 22);
   });
 
   testWidgets('injects null when rootBucket is null', (WidgetTester tester) async {
@@ -361,7 +359,7 @@ void main() {
     final BucketSpyState state = tester.state(find.byType(BucketSpy));
     expect(state.bucket, isNotNull);
 
-    binding.restorationManager.rootBucket = SynchronousFuture<RestorationBucket>(null);
+    binding.restorationManager.rootBucket = SynchronousFuture<RestorationBucket?>(null);
     await tester.pump();
     root.dispose();
 
@@ -372,7 +370,7 @@ void main() {
 }
 
 class TestAutomatedTestWidgetsFlutterBinding extends AutomatedTestWidgetsFlutterBinding {
-  MockRestorationManager _restorationManager;
+  late MockRestorationManager _restorationManager;
 
   @override
   MockRestorationManager get restorationManager => _restorationManager;

packages/flutter/test/widgets/rotated_box_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 

packages/flutter/test/widgets/route_notification_messages_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 @TestOn('chrome')
 
 import 'dart:ui';
@@ -14,7 +12,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
 class OnTapPage extends StatelessWidget {
-  const OnTapPage({Key key, this.id, this.onTap}) : super(key: key);
+  const OnTapPage({Key? key, required this.id, required this.onTap}) : super(key: key);
 
   final String id;
   final VoidCallback onTap;
@@ -28,7 +26,7 @@ class OnTapPage extends StatelessWidget {
         behavior: HitTestBehavior.opaque,
         child: Container(
           child: Center(
-            child: Text(id, style: Theme.of(context).textTheme.headline3),
+            child: Text(id, style: Theme.of(context)!.textTheme.headline3),
           ),
         ),
       ),
@@ -271,7 +269,7 @@ void main() {
     final SimpleRouterDelegate delegate = SimpleRouterDelegate(
       reportConfiguration: true,
       builder: (BuildContext context, RouteInformation information) {
-        return Text(information.location);
+        return Text(information.location!);
       }
     );
 
@@ -323,24 +321,24 @@ class SimpleRouteInformationParser extends RouteInformationParser<RouteInformati
 
 class SimpleRouterDelegate extends RouterDelegate<RouteInformation> with ChangeNotifier {
   SimpleRouterDelegate({
-    @required this.builder,
+    required this.builder,
     this.onPopRoute,
     this.reportConfiguration = false,
   });
 
   RouteInformation get routeInformation => _routeInformation;
-  RouteInformation _routeInformation;
+  late RouteInformation _routeInformation;
   set routeInformation(RouteInformation newValue) {
     _routeInformation = newValue;
     notifyListeners();
   }
 
   SimpleRouterDelegateBuilder builder;
-  SimpleRouterDelegatePopRoute onPopRoute;
+  SimpleRouterDelegatePopRoute? onPopRoute;
   final bool reportConfiguration;
 
   @override
-  RouteInformation get currentConfiguration {
+  RouteInformation? get currentConfiguration {
     if (reportConfiguration)
       return routeInformation;
     return null;
@@ -355,7 +353,7 @@ class SimpleRouterDelegate extends RouterDelegate<RouteInformation> with ChangeN
   @override
   Future<bool> popRoute() {
     if (onPopRoute != null)
-      return onPopRoute();
+      return onPopRoute!();
     return SynchronousFuture<bool>(true);
   }
 
@@ -364,7 +362,7 @@ class SimpleRouterDelegate extends RouterDelegate<RouteInformation> with ChangeN
 }
 
 class TestPage extends Page<void> {
-  const TestPage({LocalKey key, String name}) : super(key: key, name: name);
+  const TestPage({LocalKey? key, String? name}) : super(key: key, name: name);
 
   @override
   Route<void> createRoute(BuildContext context) {

packages/flutter/test/widgets/rtl_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 
@@ -26,20 +24,20 @@ void main() {
 
     await tester.pumpWidget(
       const Padding(
-        key: GlobalObjectKey<State<StatefulWidget>>(null),
+        key: GlobalObjectKey<State<StatefulWidget>>(Object()),
         padding: EdgeInsets.only(left: 1.0),
       ),
     );
     await tester.pumpWidget(const Directionality(
       textDirection: TextDirection.rtl,
       child: Padding(
-        key: GlobalObjectKey<State<StatefulWidget>>(null),
+        key: GlobalObjectKey<State<StatefulWidget>>(Object()),
         padding: EdgeInsetsDirectional.only(start: 1.0),
       ),
     ));
     await tester.pumpWidget(
       const Padding(
-        key: GlobalObjectKey<State<StatefulWidget>>(null),
+        key: GlobalObjectKey<State<StatefulWidget>>(Object()),
         padding: EdgeInsets.only(left: 1.0),
       ),
     );

packages/flutter/test/widgets/run_app_async_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:fake_async/fake_async.dart';
@@ -11,7 +9,7 @@ import 'package:fake_async/fake_async.dart';
 void main() {
   setUp(() {
     WidgetsFlutterBinding.ensureInitialized();
-    WidgetsBinding.instance.resetEpoch();
+    WidgetsBinding.instance!.resetEpoch();
   });
 
   test('WidgetBinding build rendering tree and warm up frame back to back', () {
@@ -25,9 +23,9 @@ void main() {
         ),
       );
       // Rendering tree is not built synchronously.
-      expect(WidgetsBinding.instance.renderViewElement, isNull);
+      expect(WidgetsBinding.instance!.renderViewElement, isNull);
       fakeAsync.flushTimers();
-      expect(WidgetsBinding.instance.renderViewElement, isNotNull);
+      expect(WidgetsBinding.instance!.renderViewElement, isNotNull);
     });
   });
 }

packages/flutter/test/widgets/run_app_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 

packages/flutter/test/widgets/safe_area_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';

packages/flutter/test/widgets/scroll_activity_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/material.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -167,7 +165,7 @@ class _PageView62209State extends State<PageView62209> {
 }
 
 class Carousel62209Page extends StatelessWidget {
-  const Carousel62209Page({this.number, Key key}) : super(key: key);
+  const Carousel62209Page({required this.number, Key? key}) : super(key: key);
 
   final int number;
 
@@ -178,7 +176,7 @@ class Carousel62209Page extends StatelessWidget {
 }
 
 class Carousel62209 extends StatefulWidget {
-  const Carousel62209({Key key, this.pages}) : super(key: key);
+  const Carousel62209({Key? key, required this.pages}) : super(key: key);
 
   final List<Carousel62209Page> pages;
 
@@ -188,11 +186,11 @@ class Carousel62209 extends StatefulWidget {
 
 class _Carousel62209State extends State<Carousel62209> {
   // page variables
-  PageController _pageController;
+  late PageController _pageController;
   int _currentPage = 0;
 
   // controls updates outside of user interaction
-  List<Carousel62209Page> _pages;
+  late List<Carousel62209Page> _pages;
   bool _jumpingToPage = false;
 
   @override
@@ -216,13 +214,13 @@ class _Carousel62209State extends State<Carousel62209> {
         _pages = widget.pages.toList();
       } else {
         _jumpingToPage = true;
-        SchedulerBinding.instance.addPostFrameCallback((_) {
+        SchedulerBinding.instance!.addPostFrameCallback((_) {
           if (mounted) {
             setState(() {
               _pages = widget.pages.toList();
               _currentPage = newPage;
               _pageController.jumpToPage(_currentPage);
-              SchedulerBinding.instance.addPostFrameCallback((_) {
+              SchedulerBinding.instance!.addPostFrameCallback((_) {
                 _jumpingToPage = false;
               });
             });
@@ -240,7 +238,7 @@ class _Carousel62209State extends State<Carousel62209> {
 
   bool _handleScrollNotification(ScrollNotification notification) {
     if (notification is ScrollUpdateNotification) {
-      final int page = _pageController.page.round();
+      final int page = _pageController.page!.round();
       if (!_jumpingToPage && _currentPage != page) {
         _currentPage = page;
       }

packages/flutter/test/widgets/scroll_behavior_test.dart

@@ -2,13 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/gestures.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-GestureVelocityTrackerBuilder lastCreatedBuilder;
+late GestureVelocityTrackerBuilder lastCreatedBuilder;
 class TestScrollBehavior extends ScrollBehavior {
   const TestScrollBehavior(this.flag);
 
@@ -36,15 +34,15 @@ class TestScrollBehavior extends ScrollBehavior {
 void main() {
   testWidgets('Inherited ScrollConfiguration changed', (WidgetTester tester) async {
     final GlobalKey key = GlobalKey(debugLabel: 'scrollable');
-    TestScrollBehavior behavior;
-    ScrollPositionWithSingleContext position;
+    TestScrollBehavior? behavior;
+    late ScrollPositionWithSingleContext position;
 
     final Widget scrollView = SingleChildScrollView(
       key: key,
       child: Builder(
         builder: (BuildContext context) {
           behavior = ScrollConfiguration.of(context) as TestScrollBehavior;
-          position = Scrollable.of(context).position as ScrollPositionWithSingleContext;
+          position = Scrollable.of(context)!.position as ScrollPositionWithSingleContext;
           return Container(height: 1000.0);
         },
       ),
@@ -58,7 +56,7 @@ void main() {
     );
 
     expect(behavior, isNotNull);
-    expect(behavior.flag, isTrue);
+    expect(behavior!.flag, isTrue);
     expect(position.physics, isA<ClampingScrollPhysics>());
     expect(lastCreatedBuilder(const PointerDownEvent()), isA<VelocityTracker>());
     ScrollMetrics metrics = position.copyWith();
@@ -74,7 +72,7 @@ void main() {
     );
 
     expect(behavior, isNotNull);
-    expect(behavior.flag, isFalse);
+    expect(behavior!.flag, isFalse);
     expect(position.physics, isA<BouncingScrollPhysics>());
     expect(lastCreatedBuilder(const PointerDownEvent()), isA<IOSScrollViewFlingVelocityTracker>());
     // Regression test for https://github.com/flutter/flutter/issues/5856

packages/flutter/test/widgets/scroll_controller_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 

packages/flutter/test/widgets/scroll_events_test.dart

@@ -2,15 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
-import 'package:meta/meta.dart';
 
-Widget _buildScroller({ List<String> log }) {
+Widget _buildScroller({ required List<String> log }) {
   return NotificationListener<ScrollNotification>(
     onNotification: (ScrollNotification notification) {
       if (notification is ScrollStartNotification) {
@@ -29,7 +26,7 @@ Widget _buildScroller({ List<String> log }) {
 }
 
 void main() {
-  Completer<void> animateTo(WidgetTester tester, double newScrollOffset, { @required Duration duration }) {
+  Completer<void> animateTo(WidgetTester tester, double newScrollOffset, { required Duration duration }) {
     final Completer<void> completer = Completer<void>();
     final ScrollableState scrollable = tester.state(find.byType(Scrollable));
     scrollable.position.animateTo(newScrollOffset, duration: duration, curve: Curves.linear).whenComplete(completer.complete);

packages/flutter/test/widgets/scroll_interaction_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 

packages/flutter/test/widgets/scroll_notification_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
@@ -11,7 +9,7 @@ import 'package:flutter/widgets.dart';
 
 void main() {
   testWidgets('Scroll notification basics', (WidgetTester tester) async {
-    ScrollNotification notification;
+    late ScrollNotification notification;
 
     await tester.pumpWidget(NotificationListener<ScrollNotification>(
       onNotification: (ScrollNotification value) {
@@ -30,7 +28,7 @@ void main() {
     expect(notification.depth, equals(0));
     final ScrollStartNotification start = notification as ScrollStartNotification;
     expect(start.dragDetails, isNotNull);
-    expect(start.dragDetails.globalPosition, equals(const Offset(100.0, 100.0)));
+    expect(start.dragDetails!.globalPosition, equals(const Offset(100.0, 100.0)));
 
     await gesture.moveBy(const Offset(-10.0, -10.0));
     await tester.pump(const Duration(seconds: 1));
@@ -38,8 +36,8 @@ void main() {
     expect(notification.depth, equals(0));
     final ScrollUpdateNotification update = notification as ScrollUpdateNotification;
     expect(update.dragDetails, isNotNull);
-    expect(update.dragDetails.globalPosition, equals(const Offset(90.0, 90.0)));
-    expect(update.dragDetails.delta, equals(const Offset(0.0, -10.0)));
+    expect(update.dragDetails!.globalPosition, equals(const Offset(90.0, 90.0)));
+    expect(update.dragDetails!.delta, equals(const Offset(0.0, -10.0)));
 
     await gesture.up();
     await tester.pump(const Duration(seconds: 1));
@@ -47,7 +45,7 @@ void main() {
     expect(notification.depth, equals(0));
     final ScrollEndNotification end = notification as ScrollEndNotification;
     expect(end.dragDetails, isNotNull);
-    expect(end.dragDetails.velocity, equals(Velocity.zero));
+    expect(end.dragDetails!.velocity, equals(Velocity.zero));
   });
 
   testWidgets('Scroll notification depth', (WidgetTester tester) async {

packages/flutter/test/widgets/scroll_physics_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
@@ -12,20 +10,20 @@ import 'package:flutter_test/flutter_test.dart';
 
 class TestScrollPhysics extends ScrollPhysics {
   const TestScrollPhysics({
-    this.name,
-    ScrollPhysics parent
+    required this.name,
+    ScrollPhysics? parent
   }) : super(parent: parent);
   final String name;
 
   @override
-  TestScrollPhysics applyTo(ScrollPhysics ancestor) {
+  TestScrollPhysics applyTo(ScrollPhysics? ancestor) {
     return TestScrollPhysics(
       name: name,
-      parent: parent?.applyTo(ancestor) ?? ancestor,
+      parent: parent?.applyTo(ancestor) ?? ancestor!,
     );
   }
 
-  TestScrollPhysics get namedParent => parent as TestScrollPhysics;
+  TestScrollPhysics get namedParent => parent! as TestScrollPhysics;
   String get names => parent == null ? name : '$name ${namedParent.names}';
 
   @override
@@ -69,7 +67,7 @@ void main() {
     const ScrollPhysics always = AlwaysScrollableScrollPhysics();
     const ScrollPhysics page = PageScrollPhysics();
 
-    String types(ScrollPhysics s) => s.parent == null ? '${s.runtimeType}' : '${s.runtimeType} ${types(s.parent)}';
+    String types(ScrollPhysics? value) => value!.parent == null ? '${value.runtimeType}' : '${value.runtimeType} ${types(value.parent)}';
 
     expect(
       types(bounce.applyTo(clamp.applyTo(never.applyTo(always.applyTo(page))))),
@@ -112,13 +110,13 @@ void main() {
 
     // Calls to createBallisticSimulation may happen on every frame (i.e. when the maxScrollExtent changes)
     // Changing velocity for time 0 may cause a sudden, unwanted damping/speedup effect
-    expect(bounce.createBallisticSimulation(position, 1000).dx(0), moreOrLessEquals(1000));
-    expect(clamp.createBallisticSimulation(position, 1000).dx(0), moreOrLessEquals(1000));
-    expect(page.createBallisticSimulation(position, 1000).dx(0), moreOrLessEquals(1000));
+    expect(bounce.createBallisticSimulation(position, 1000)!.dx(0), moreOrLessEquals(1000));
+    expect(clamp.createBallisticSimulation(position, 1000)!.dx(0), moreOrLessEquals(1000));
+    expect(page.createBallisticSimulation(position, 1000)!.dx(0), moreOrLessEquals(1000));
   });
 
   group('BouncingScrollPhysics test', () {
-    BouncingScrollPhysics physicsUnderTest;
+    late BouncingScrollPhysics physicsUnderTest;
 
     setUp(() {
       physicsUnderTest = const BouncingScrollPhysics();
@@ -253,7 +251,7 @@ void main() {
       axisDirection: AxisDirection.down,
     );
     expect(position.pixels, pixels);
-    FlutterError error;
+    late FlutterError error;
     try {
       physics.applyBoundaryConditions(position, pixels);
     } on FlutterError catch (e) {

packages/flutter/test/widgets/scroll_position_test.dart

@@ -2,11 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:ui';
 
-import 'package:meta/meta.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 
@@ -16,8 +13,8 @@ ScrollController _controller = ScrollController(
 
 class ThePositiveNumbers extends StatelessWidget {
   const ThePositiveNumbers({
-    Key key,
-    @required this.from,
+    Key? key,
+    required this.from,
   }) : super(key: key);
   final int from;
   @override
@@ -93,7 +90,7 @@ Future<void> performTest(WidgetTester tester, bool maintainState) async {
   expect(find.text('16'), findsNothing, reason: 'with maintainState: $maintainState');
   expect(find.text('100'), findsNothing, reason: 'with maintainState: $maintainState');
 
-  navigatorKey.currentState.pushNamed('/second');
+  navigatorKey.currentState!.pushNamed('/second');
   await tester.pump(); // navigating always takes two frames, one to start...
   await tester.pump(const Duration(seconds: 1)); // ...and one to end the transition
 
@@ -114,7 +111,7 @@ Future<void> performTest(WidgetTester tester, bool maintainState) async {
   expect(find.text('10010'), findsNothing, reason: 'with maintainState: $maintainState');
   expect(find.text('10100'), findsNothing, reason: 'with maintainState: $maintainState');
 
-  navigatorKey.currentState.pop();
+  navigatorKey.currentState!.pop();
   await tester.pump(); // again, navigating always takes two frames
 
   // Ensure we don't clamp the scroll offset even during the navigation.

packages/flutter/test/widgets/scroll_simulation_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 

packages/flutter/test/widgets/scrollable_animations_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';
@@ -71,10 +69,10 @@ void main() {
     final double targetPosition = controller.position.pixels + doubleTolerance;
     controller.position.animateTo(targetPosition, duration: const Duration(seconds: 10), curve: Curves.linear);
 
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(1), reason: 'Expected an animation.');
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(1), reason: 'Expected an animation.');
   });
 }
 
 void expectNoAnimation() {
-  expect(SchedulerBinding.instance.transientCallbackCount, equals(0), reason: 'Expected no animation.');
+  expect(SchedulerBinding.instance!.transientCallbackCount, equals(0), reason: 'Expected no animation.');
 }

packages/flutter/test/widgets/scrollable_dispose_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';

packages/flutter/test/widgets/scrollable_fling_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/gestures.dart' show DragStartBehavior;

packages/flutter/test/widgets/scrollable_grid_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter/rendering.dart';

packages/flutter/test/widgets/scrollable_in_overlay_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';

packages/flutter/test/widgets/scrollable_list_hit_testing_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';

packages/flutter/test/widgets/scrollable_of_test.dart

@@ -2,13 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 
 class ScrollPositionListener extends StatefulWidget {
-  const ScrollPositionListener({ Key key, this.child, this.log}) : super(key: key);
+  const ScrollPositionListener({ Key? key, required this.child, required this.log}) : super(key: key);
 
   final Widget child;
   final ValueChanged<String> log;
@@ -18,7 +16,7 @@ class ScrollPositionListener extends StatefulWidget {
 }
 
 class _ScrollPositionListenerState extends State<ScrollPositionListener> {
-  ScrollPosition _position;
+  ScrollPosition? _position;
 
   @override
   void didChangeDependencies() {
@@ -26,7 +24,7 @@ class _ScrollPositionListenerState extends State<ScrollPositionListener> {
     _position?.removeListener(listener);
     _position = Scrollable.of(context)?.position;
     _position?.addListener(listener);
-    widget.log('didChangeDependencies ${_position?.pixels?.toStringAsFixed(1)}');
+    widget.log('didChangeDependencies ${_position?.pixels.toStringAsFixed(1)}');
   }
 
   @override
@@ -39,20 +37,20 @@ class _ScrollPositionListenerState extends State<ScrollPositionListener> {
   Widget build(BuildContext context) => widget.child;
 
   void listener() {
-    widget.log('listener ${_position?.pixels?.toStringAsFixed(1)}');
+    widget.log('listener ${_position?.pixels.toStringAsFixed(1)}');
   }
 
 }
 
 void main() {
   testWidgets('Scrollable.of() dependent rebuilds when Scrollable position changes', (WidgetTester tester) async {
-    String logValue;
+    late String logValue;
     final ScrollController controller = ScrollController();
 
     // Changing the SingleChildScrollView's physics causes the
     // ScrollController's ScrollPosition to be rebuilt.
 
-    Widget buildFrame(ScrollPhysics physics) {
+    Widget buildFrame(ScrollPhysics? physics) {
       return SingleChildScrollView(
         controller: controller,
         physics: physics,
@@ -86,7 +84,7 @@ void main() {
   });
 
   testWidgets('Scrollable.of() is possible using ScrollNotification context', (WidgetTester tester) async {
-    ScrollNotification notification;
+    late ScrollNotification notification;
 
     await tester.pumpWidget(NotificationListener<ScrollNotification>(
       onNotification: (ScrollNotification value) {
@@ -102,6 +100,6 @@ void main() {
     await tester.pump(const Duration(seconds: 1));
 
     final StatefulElement scrollableElement = find.byType(Scrollable).evaluate().first as StatefulElement;
-    expect(Scrollable.of(notification.context), equals(scrollableElement.state));
+    expect(Scrollable.of(notification.context!), equals(scrollableElement.state));
   });
 }

packages/flutter/test/widgets/scrollable_restoration_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -397,20 +395,20 @@ void main() {
       ),
     );
 
-    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry.paintExtent, 150);
+    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry!.paintExtent, 150);
     expect(find.text('Tile 0'), findsOneWidget);
     expect(find.text('Tile 10'), findsNothing);
 
     await tester.drag(find.byType(ListView), const Offset(0, -500));
     await tester.pump();
 
-    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry.paintExtent, 56);
+    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry!.paintExtent, 56);
     expect(find.text('Tile 0'), findsNothing);
     expect(find.text('Tile 10'), findsOneWidget);
 
     await tester.restartAndRestore();
 
-    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry.paintExtent, 56);
+    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry!.paintExtent, 56);
     expect(find.text('Tile 0'), findsNothing);
     expect(find.text('Tile 10'), findsOneWidget);
 
@@ -418,13 +416,13 @@ void main() {
     await tester.drag(find.byType(ListView), const Offset(0, 600));
     await tester.pump();
 
-    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry.paintExtent, 150);
+    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry!.paintExtent, 150);
     expect(find.text('Tile 0'), findsOneWidget);
     expect(find.text('Tile 10'), findsNothing);
 
     await tester.restoreFrom(data);
 
-    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry.paintExtent, 56);
+    expect(tester.renderObject<RenderSliver>(find.byType(SliverAppBar)).geometry!.paintExtent, 56);
     expect(find.text('Tile 0'), findsNothing);
     expect(find.text('Tile 10'), findsOneWidget);
   });
@@ -552,7 +550,7 @@ Future<void> restoreScrollAndVerify(WidgetTester tester, {double secondOffset =
 }
 
 class TestHarness extends StatelessWidget {
-  const TestHarness({Key key, this.child, this.height = 100}) : super(key: key);
+  const TestHarness({Key? key, required this.child, this.height = 100}) : super(key: key);
 
   final Widget child;
   final double height;