Migrate more material tests (#67591)

packages/flutter/test/material/tabs_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';
@@ -11,11 +9,12 @@ import 'package:flutter/widgets.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/physics.dart';
 
+import '../flutter_test_alternative.dart' show Fake;
 import '../rendering/mock_canvas.dart';
 import '../rendering/recording_canvas.dart';
 import '../widgets/semantics_tester.dart';
 
-Widget boilerplate({ Widget child, TextDirection textDirection = TextDirection.ltr }) {
+Widget boilerplate({ Widget? child, TextDirection textDirection = TextDirection.ltr }) {
   return Localizations(
     locale: const Locale('en', 'US'),
     delegates: const <LocalizationsDelegate<dynamic>>[
@@ -32,27 +31,27 @@ Widget boilerplate({ Widget child, TextDirection textDirection = TextDirection.l
 }
 
 class StateMarker extends StatefulWidget {
-  const StateMarker({ Key key, this.child }) : super(key: key);
+  const StateMarker({ Key? key, this.child }) : super(key: key);
 
-  final Widget child;
+  final Widget? child;
 
   @override
   StateMarkerState createState() => StateMarkerState();
 }
 
 class StateMarkerState extends State<StateMarker> {
-  String marker;
+  String? marker;
 
   @override
   Widget build(BuildContext context) {
     if (widget.child != null)
-      return widget.child;
+      return widget.child!;
     return Container();
   }
 }
 
 class AlwaysKeepAliveWidget extends StatefulWidget {
-  const AlwaysKeepAliveWidget({ Key key}) : super(key: key);
+  const AlwaysKeepAliveWidget({ Key? key}) : super(key: key);
   static String text = 'AlwaysKeepAlive';
   @override
   AlwaysKeepAliveState createState() => AlwaysKeepAliveState();
@@ -75,7 +74,7 @@ class _NestedTabBarContainer extends StatelessWidget {
     this.tabController,
   });
 
-  final TabController tabController;
+  final TabController? tabController;
 
   @override
   Widget build(BuildContext context) {
@@ -107,11 +106,11 @@ class _NestedTabBarContainer extends StatelessWidget {
 }
 
 Widget buildFrame({
-  Key tabBarKey,
-  List<String> tabs,
-  String value,
+  Key? tabBarKey,
+  required List<String> tabs,
+  required String value,
   bool isScrollable = false,
-  Color indicatorColor,
+  Color? indicatorColor,
 }) {
   return boilerplate(
     child: DefaultTabController(
@@ -131,10 +130,10 @@ typedef TabControllerFrameBuilder = Widget Function(BuildContext context, TabCon
 
 class TabControllerFrame extends StatefulWidget {
   const TabControllerFrame({
-    Key key,
-    this.length,
+    Key? key,
+    required this.length,
     this.initialIndex = 0,
-    this.builder,
+    required this.builder,
   }) : super(key: key);
 
   final int length;
@@ -146,7 +145,7 @@ class TabControllerFrame extends StatefulWidget {
 }
 
 class TabControllerFrameState extends State<TabControllerFrame> with SingleTickerProviderStateMixin {
-  TabController _controller;
+  late TabController _controller;
 
   @override
   void initState() {
@@ -170,7 +169,7 @@ class TabControllerFrameState extends State<TabControllerFrame> with SingleTicke
   }
 }
 
-Widget buildLeftRightApp({ List<String> tabs, String value }) {
+Widget buildLeftRightApp({ required List<String> tabs, required String value }) {
   return MaterialApp(
     theme: ThemeData(platform: TargetPlatform.android),
     home: DefaultTabController(
@@ -198,7 +197,7 @@ class TabIndicatorRecordingCanvas extends TestRecordingCanvas {
   TabIndicatorRecordingCanvas(this.indicatorColor);
 
   final Color indicatorColor;
-  Rect indicatorRect;
+  late Rect indicatorRect;
 
   @override
   void drawLine(Offset p1, Offset p2, Paint paint) {
@@ -210,10 +209,10 @@ class TabIndicatorRecordingCanvas extends TestRecordingCanvas {
 }
 
 class TestScrollPhysics extends ScrollPhysics {
-  const TestScrollPhysics({ ScrollPhysics parent }) : super(parent: parent);
+  const TestScrollPhysics({ ScrollPhysics? parent }) : super(parent: parent);
 
   @override
-  TestScrollPhysics applyTo(ScrollPhysics ancestor) {
+  TestScrollPhysics applyTo(ScrollPhysics? ancestor) {
     return TestScrollPhysics(parent: buildParent(ancestor));
   }
 
@@ -255,7 +254,7 @@ void main() {
     await tester.pumpWidget(
       MaterialApp(theme: ThemeData(fontFamily: 'Ahem'), home: const Center(child: Material(child: Tab(text: 'x')))),
     );
-    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style.fontFamily, 'Ahem');
+    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style!.fontFamily, 'Ahem');
     expect(tester.getSize(find.byType(Tab)), const Size(14.0, 46.0));
   });
 
@@ -263,7 +262,7 @@ void main() {
     await tester.pumpWidget(
       MaterialApp(theme: ThemeData(fontFamily: 'Ahem'), home: const Center(child: Material(child: Tab(icon: SizedBox(width: 10.0, height: 10.0), text: 'x')))),
     );
-    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style.fontFamily, 'Ahem');
+    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style!.fontFamily, 'Ahem');
     expect(tester.getSize(find.byType(Tab)), const Size(14.0, 72.0));
   });
 
@@ -287,7 +286,7 @@ void main() {
         ),
       ),
     );
-    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style.fontFamily, 'Ahem');
+    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style!.fontFamily, 'Ahem');
     expect(tester.getSize(find.byType(Tab)), const Size(210.0, 72.0));
   });
 
@@ -295,7 +294,7 @@ void main() {
     await tester.pumpWidget(
       MaterialApp(theme: ThemeData(fontFamily: 'Ahem'), home: const Center(child: Material(child: Tab(icon: SizedBox(width: 10.0, height: 10.0), child: Text('x'))))),
     );
-    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style.fontFamily, 'Ahem');
+    expect(tester.renderObject<RenderParagraph>(find.byType(RichText)).text.style!.fontFamily, 'Ahem');
     expect(tester.getSize(find.byType(Tab)), const Size(14.0, 72.0));
   });
 
@@ -330,7 +329,7 @@ void main() {
     expect(find.text('A'), findsOneWidget);
     expect(find.text('B'), findsOneWidget);
     expect(find.text('C'), findsOneWidget);
-    final TabController controller = DefaultTabController.of(tester.element(find.text('A')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('A')))!;
     expect(controller, isNotNull);
     expect(controller.index, 2);
     expect(controller.previousIndex, 2);
@@ -366,7 +365,7 @@ void main() {
     expect(find.text('A'), findsOneWidget);
     expect(find.text('B'), findsOneWidget);
     expect(find.text('C'), findsOneWidget);
-    final TabController controller = DefaultTabController.of(tester.element(find.text('A')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('A')))!;
     expect(controller.index, 2);
     expect(controller.previousIndex, 2);
 
@@ -387,7 +386,7 @@ void main() {
     final List<String> tabs = <String>['AAAAAA', 'BBBBBB', 'CCCCCC', 'DDDDDD', 'EEEEEE', 'FFFFFF', 'GGGGGG', 'HHHHHH', 'IIIIII', 'JJJJJJ', 'KKKKKK', 'LLLLLL'];
     const Key tabBarKey = Key('TabBar');
     await tester.pumpWidget(buildFrame(tabs: tabs, value: 'AAAAAA', isScrollable: true, tabBarKey: tabBarKey));
-    final TabController controller = DefaultTabController.of(tester.element(find.text('AAAAAA')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('AAAAAA')))!;
     expect(controller, isNotNull);
     expect(controller.index, 0);
 
@@ -407,7 +406,7 @@ void main() {
     final List<String> tabs = <String>['AAAA', 'BBBB', 'CCCC', 'DDDD', 'EEEE', 'FFFF', 'GGGG', 'HHHH', 'IIII', 'JJJJ', 'KKKK', 'LLLL'];
     const Key tabBarKey = Key('TabBar');
     await tester.pumpWidget(buildFrame(tabs: tabs, value: 'AAAA', isScrollable: true, tabBarKey: tabBarKey));
-    final TabController controller = DefaultTabController.of(tester.element(find.text('AAAA')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('AAAA')))!;
     expect(controller, isNotNull);
     expect(controller.index, 0);
 
@@ -447,7 +446,7 @@ void main() {
     }
 
     await tester.pumpWidget(builder());
-    final TabController controller = DefaultTabController.of(tester.element(find.text('AAAAAA')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('AAAAAA')))!;
 
     TestGesture gesture = await tester.startGesture(tester.getCenter(find.text(tabs[0])));
     await gesture.moveBy(const Offset(-600.0, 0.0));
@@ -504,7 +503,7 @@ void main() {
     expect(find.text('LEFT CHILD'), findsOneWidget);
     expect(find.text('RIGHT CHILD'), findsNothing);
 
-    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')))!;
     expect(controller.index, 0);
 
     // Fling to the left, switch from the 'LEFT' tab to the 'RIGHT'
@@ -533,7 +532,7 @@ void main() {
     expect(find.text('LEFT CHILD'), findsOneWidget);
     expect(find.text('RIGHT CHILD'), findsNothing);
 
-    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')))!;
     expect(controller.index, 0);
 
     final Offset flingStart = tester.getCenter(find.text('LEFT CHILD'));
@@ -554,7 +553,7 @@ void main() {
     expect(find.text('LEFT CHILD'), findsOneWidget);
     expect(find.text('RIGHT CHILD'), findsNothing);
 
-    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')))!;
     expect(controller.index, 0);
 
     final Offset flingStart = tester.getCenter(find.text('LEFT CHILD'));
@@ -577,7 +576,7 @@ void main() {
     expect(find.text('LEFT CHILD'), findsOneWidget);
     expect(find.text('RIGHT CHILD'), findsNothing);
 
-    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')))!;
     expect(controller.index, 0);
 
     final Offset flingStart = tester.getCenter(find.text('LEFT CHILD'));
@@ -645,12 +644,12 @@ void main() {
     final List<String> tabs = <String>['LEFT', 'RIGHT'];
 
     await tester.pumpWidget(buildLeftRightApp(tabs: tabs, value: 'LEFT'));
-    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')));
+    final TabController controller = DefaultTabController.of(tester.element(find.text('LEFT')))!;
 
     expect(controller, isNotNull);
     expect(controller.index, 0);
 
-    String value;
+    late String value;
     controller.addListener(() {
       value = tabs[controller.index];
     });
@@ -676,7 +675,7 @@ void main() {
 
   testWidgets('Explicit TabController', (WidgetTester tester) async {
     final List<String> tabs = <String>['LEFT', 'RIGHT'];
-    TabController tabController;
+    late TabController tabController;
 
     Widget buildTabControllerFrame(BuildContext context, TabController controller) {
       tabController = controller;
@@ -714,8 +713,8 @@ void main() {
     expect(tabController.index, 1);
     expect(tabController.previousIndex, 1);
     expect(tabController.indexIsChanging, false);
-    expect(tabController.animation.value, 1.0);
-    expect(tabController.animation.status, AnimationStatus.forward);
+    expect(tabController.animation!.value, 1.0);
+    expect(tabController.animation!.status, AnimationStatus.forward);
 
     tabController.index = 0;
     await tester.pump(const Duration(milliseconds: 500));
@@ -735,7 +734,7 @@ void main() {
     // https://github.com/flutter/flutter/pull/7387#pullrequestreview-15630946
 
     final List<String> tabs = <String>['A', 'B', 'C'];
-    TabController tabController;
+    late TabController tabController;
 
     Widget buildTabControllerFrame(BuildContext context, TabController controller) {
       tabController = controller;
@@ -766,8 +765,8 @@ void main() {
       length: tabs.length,
     ));
 
-    tabController.animation.addListener(() {
-      if (tabController.animation.status == AnimationStatus.forward)
+    tabController.animation!.addListener(() {
+      if (tabController.animation!.status == AnimationStatus.forward)
         tabController.index = 2;
       expect(tabController.indexIsChanging, true);
     });
@@ -803,8 +802,8 @@ void main() {
       length: 2,
     );
 
-    Color firstColor;
-    Color secondColor;
+    late Color firstColor;
+    late Color secondColor;
 
     await tester.pumpWidget(
       boilerplate(
@@ -815,13 +814,13 @@ void main() {
           tabs: <Widget>[
             Builder(
               builder: (BuildContext context) {
-                firstColor = IconTheme.of(context).color;
+                firstColor = IconTheme.of(context).color!;
                 return const Text('First');
               }
             ),
             Builder(
               builder: (BuildContext context) {
-                secondColor = IconTheme.of(context).color;
+                secondColor = IconTheme.of(context).color!;
                 return const Text('Second');
               }
             ),
@@ -1175,7 +1174,7 @@ void main() {
     );
 
     final TabBar tabBar = tester.widget(find.byType(TabBar));
-    final double position = tabBar.physics.applyPhysicsToUserOffset(null, 10);
+    final double position = tabBar.physics!.applyPhysicsToUserOffset(MockScrollMetrics(), 10);
 
     expect(position, equals(20));
   });
@@ -1438,7 +1437,7 @@ void main() {
     double tabTop = (tabBarHeight - indicatorWeight - 30.0) / 2.0;
     double tabBottom = tabTop + 30.0;
     Rect tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[0].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[0].key!)), tabRect);
 
 
     // Tab1 width = 140, height = 40
@@ -1447,7 +1446,7 @@ void main() {
     tabTop = (tabBarHeight - indicatorWeight - 40.0) / 2.0;
     tabBottom = tabTop + 40.0;
     tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[1].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[1].key!)), tabRect);
 
 
     // Tab2 width = 150, height = 50
@@ -1456,7 +1455,7 @@ void main() {
     tabTop = (tabBarHeight - indicatorWeight - 50.0) / 2.0;
     tabBottom = tabTop + 50.0;
     tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[2].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[2].key!)), tabRect);
 
     // Tab 0 selected, indicator padding resolves to left: 100.0
     const double indicatorLeft = 100.0 + indicatorWeight / 2.0;
@@ -1508,7 +1507,7 @@ void main() {
     double tabTop = (tabBarHeight - indicatorWeight - 50.0) / 2.0;
     double tabBottom = tabTop + 50.0;
     Rect tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[2].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[2].key!)), tabRect);
 
     // Tab1 width = 140, height = 40
     tabLeft = tabRight + kTabLabelPadding.right + kTabLabelPadding.left;
@@ -1516,7 +1515,7 @@ void main() {
     tabTop = (tabBarHeight - indicatorWeight - 40.0) / 2.0;
     tabBottom = tabTop + 40.0;
     tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[1].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[1].key!)), tabRect);
 
     // Tab0 width = 130, height = 30
     tabLeft = tabRight + kTabLabelPadding.right + kTabLabelPadding.left;
@@ -1524,7 +1523,7 @@ void main() {
     tabTop = (tabBarHeight - indicatorWeight - 30.0) / 2.0;
     tabBottom = tabTop + 30.0;
     tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[0].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[0].key!)), tabRect);
 
     // Tab 0 selected, indicator padding resolves to right: 100.0
     final double indicatorLeft = tabLeft - kTabLabelPadding.left + indicatorWeight / 2.0;
@@ -1578,7 +1577,7 @@ void main() {
     double tabTop = (tabBarHeight - indicatorWeight - 30.0) / 2.0;
     double tabBottom = tabTop + 30.0;
     Rect tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[0].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[0].key!)), tabRect);
 
     // Tab1 width = 140, height = 40
     tabLeft = tabRight + labelPadding.right + labelPadding.left;
@@ -1586,7 +1585,7 @@ void main() {
     tabTop = (tabBarHeight - indicatorWeight - 40.0) / 2.0;
     tabBottom = tabTop + 40.0;
     tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[1].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[1].key!)), tabRect);
 
     // Tab2 width = 150, height = 50
     tabLeft = tabRight + labelPadding.right + labelPadding.left;
@@ -1594,7 +1593,7 @@ void main() {
     tabTop = (tabBarHeight - indicatorWeight - 50.0) / 2.0;
     tabBottom = tabTop + 50.0;
     tabRect = Rect.fromLTRB(tabLeft, tabTop, tabRight, tabBottom);
-    expect(tester.getRect(find.byKey(tabs[2].key)), tabRect);
+    expect(tester.getRect(find.byKey(tabs[2].key!)), tabRect);
 
     // Tab 0 selected, indicatorPadding == labelPadding
     final double indicatorLeft = indicatorPadding.left + indicatorWeight / 2.0;
@@ -2018,8 +2017,8 @@ void main() {
     int tabIndex = -1;
 
     Widget buildFrame({
-      TabController controller,
-      List<String> tabs,
+      required TabController controller,
+      required List<String> tabs,
     }) {
       return boilerplate(
         child: Container(
@@ -2123,7 +2122,7 @@ void main() {
 
     await tester.pump();
 
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
 
     // Test default cursor
     await tester.pumpWidget(MaterialApp(home: DefaultTabController(
@@ -2138,7 +2137,7 @@ void main() {
         ),
       ),
     ));
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.click);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.click);
   });
 
   testWidgets('TabController changes', (WidgetTester tester) async {
@@ -2330,7 +2329,7 @@ void main() {
     ];
     final TabController controller = TabController(vsync: const TestVSync(), length: tabs.length);
 
-    Widget buildTestWidget({double width, double height}) {
+    Widget buildTestWidget({double? width, double? height}) {
       return MaterialApp(
         home: Center(
           child: SizedBox(
@@ -2398,7 +2397,7 @@ void main() {
         ),
       );
     }
-    TabController getController() => DefaultTabController.of(tester.element(find.text('A')));
+    TabController getController() => DefaultTabController.of(tester.element(find.text('A')))!;
 
     await tester.pumpWidget(buildTabs(threeTabs));
     await tester.tap(find.text('B'));
@@ -2593,7 +2592,7 @@ void main() {
       Tab(text: 'A'), Tab(text: 'B'), Tab(text: 'C')
     ];
     const Color indicatorColor = Color(0xFFFF0000);
-    TabController tabController;
+    late TabController tabController;
 
     Widget buildTabControllerFrame(BuildContext context, TabController controller) {
       tabController = controller;
@@ -2609,7 +2608,7 @@ void main() {
           body: TabBarView(
             controller: controller,
             children: tabs.map((Tab tab) {
-              return Center(child: Text(tab.text));
+              return Center(child: Text(tab.text!));
             }).toList(),
           ),
         ),
@@ -2677,8 +2676,8 @@ void main() {
       length: 2,
     );
 
-    Color firstColor;
-    Color secondColor;
+    late Color firstColor;
+    late Color secondColor;
 
     await tester.pumpWidget(
       boilerplate(
@@ -2688,11 +2687,11 @@ void main() {
           unselectedLabelColor: Colors.black,
           tabs: <Widget>[
             Builder(builder: (BuildContext context) {
-              firstColor = DefaultTextStyle.of(context).style.color;
+              firstColor = DefaultTextStyle.of(context).style.color!;
               return const Text('First');
             }),
             Builder(builder: (BuildContext context) {
-              secondColor = DefaultTextStyle.of(context).style.color;
+              secondColor = DefaultTextStyle.of(context).style.color!;
               return const Text('Second');
             }),
           ],
@@ -2764,18 +2763,18 @@ void main() {
 
     pageController.jumpTo(300.0);
     await tester.pump();
-    expect(tabController.animation.value, pageController.page);
+    expect(tabController.animation!.value, pageController.page);
 
     // Touch TabBarView while ballistic scrolling is happening and
     // check if tabController's animation value properly follows page value.
     await tester.startGesture(tester.getCenter(find.byType(PageView)));
     await tester.pump();
-    expect(tabController.animation.value, pageController.page);
+    expect(tabController.animation!.value, pageController.page);
   });
 }
 
 class KeepAliveInk extends StatefulWidget {
-  const KeepAliveInk(this.title, {Key key}) : super(key: key);
+  const KeepAliveInk(this.title, {Key? key}) : super(key: key);
   final String title;
   @override
   State<StatefulWidget> createState() {
@@ -2825,3 +2824,5 @@ class TabBarDemo extends StatelessWidget {
     );
   }
 }
+
+class MockScrollMetrics extends Fake implements ScrollMetrics {}

packages/flutter/test/material/text_button_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:flutter/gestures.dart';
@@ -43,10 +41,10 @@ void main() {
     expect(material.elevation, 0.0);
     expect(material.shadowColor, const Color(0xff000000));
     expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4.0)));
-    expect(material.textStyle.color, colorScheme.primary);
-    expect(material.textStyle.fontFamily, 'Roboto');
-    expect(material.textStyle.fontSize, 14);
-    expect(material.textStyle.fontWeight, FontWeight.w500);
+    expect(material.textStyle!.color, colorScheme.primary);
+    expect(material.textStyle!.fontFamily, 'Roboto');
+    expect(material.textStyle!.fontSize, 14);
+    expect(material.textStyle!.fontWeight, FontWeight.w500);
     expect(material.type, MaterialType.button);
 
     final Offset center = tester.getCenter(find.byType(TextButton));
@@ -68,10 +66,10 @@ void main() {
     expect(material.elevation, 0.0);
     expect(material.shadowColor, const Color(0xff000000));
     expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4.0)));
-    expect(material.textStyle.color, colorScheme.primary);
-    expect(material.textStyle.fontFamily, 'Roboto');
-    expect(material.textStyle.fontSize, 14);
-    expect(material.textStyle.fontWeight, FontWeight.w500);
+    expect(material.textStyle!.color, colorScheme.primary);
+    expect(material.textStyle!.fontFamily, 'Roboto');
+    expect(material.textStyle!.fontSize, 14);
+    expect(material.textStyle!.fontWeight, FontWeight.w500);
     expect(material.type, MaterialType.button);
 
     // Disabled TextButton
@@ -96,10 +94,10 @@ void main() {
     expect(material.elevation, 0.0);
     expect(material.shadowColor, const Color(0xff000000));
     expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4.0)));
-    expect(material.textStyle.color, colorScheme.onSurface.withOpacity(0.38));
-    expect(material.textStyle.fontFamily, 'Roboto');
-    expect(material.textStyle.fontSize, 14);
-    expect(material.textStyle.fontWeight, FontWeight.w500);
+    expect(material.textStyle!.color, colorScheme.onSurface.withOpacity(0.38));
+    expect(material.textStyle!.fontFamily, 'Roboto');
+    expect(material.textStyle!.fontSize, 14);
+    expect(material.textStyle!.fontWeight, FontWeight.w500);
     expect(material.type, MaterialType.button);
   });
 
@@ -161,9 +159,9 @@ void main() {
         MaterialState.focused,
       };
       if (states.any(interactiveStates.contains)) {
-        return Colors.blue[900];
+        return Colors.blue[900]!;
       }
-      return Colors.blue[800];
+      return Colors.blue[800]!;
     }
 
     await tester.pumpWidget(
@@ -258,8 +256,8 @@ void main() {
       ),
     );
 
-    Color textColor() {
-      return tester.renderObject<RenderParagraph>(find.text('TextButton')).text.style.color;
+    Color? textColor() {
+      return tester.renderObject<RenderParagraph>(find.text('TextButton')).text.style?.color;
     }
 
     // Default, not disabled.
@@ -329,7 +327,7 @@ void main() {
       ),
     );
 
-    Color iconColor() => _iconStyle(tester, Icons.add).color;
+    Color? iconColor() => _iconStyle(tester, Icons.add)?.color;
     // Default, not disabled.
     expect(iconColor(), equals(defaultColor));
 
@@ -378,7 +376,7 @@ void main() {
   testWidgets('Does TextButton work with hover', (WidgetTester tester) async {
     const Color hoverColor = Color(0xff001122);
 
-    Color getOverlayColor(Set<MaterialState> states) {
+    Color? getOverlayColor(Set<MaterialState> states) {
       return states.contains(MaterialState.hovered) ? hoverColor : null;
     }
 
@@ -388,7 +386,7 @@ void main() {
         child: Material(
           child: TextButton(
             style: ButtonStyle(
-              overlayColor: MaterialStateProperty.resolveWith<Color>(getOverlayColor),
+              overlayColor: MaterialStateProperty.resolveWith<Color?>(getOverlayColor),
             ),
             child: Container(),
             onPressed: () { /* to make sure the button is enabled */ },
@@ -411,7 +409,7 @@ void main() {
   testWidgets('Does TextButton work with focus', (WidgetTester tester) async {
     const Color focusColor = Color(0xff001122);
 
-    Color getOverlayColor(Set<MaterialState> states) {
+    Color? getOverlayColor(Set<MaterialState> states) {
       return states.contains(MaterialState.focused) ? focusColor : null;
     }
 
@@ -421,7 +419,7 @@ void main() {
         textDirection: TextDirection.ltr,
         child: TextButton(
           style: ButtonStyle(
-            overlayColor: MaterialStateProperty.resolveWith<Color>(getOverlayColor),
+            overlayColor: MaterialStateProperty.resolveWith<Color?>(getOverlayColor),
           ),
           focusNode: focusNode,
           onPressed: () { },
@@ -430,7 +428,7 @@ void main() {
       ),
     );
 
-    WidgetsBinding.instance.focusManager.highlightStrategy = FocusHighlightStrategy.alwaysTraditional;
+    WidgetsBinding.instance!.focusManager.highlightStrategy = FocusHighlightStrategy.alwaysTraditional;
     focusNode.requestFocus();
     await tester.pumpAndSettle();
 
@@ -590,7 +588,7 @@ void main() {
     bool wasPressed;
     Finder textButton;
 
-    Widget buildFrame({ VoidCallback onPressed, VoidCallback onLongPress }) {
+    Widget buildFrame({ VoidCallback? onPressed, VoidCallback? onLongPress }) {
       return Directionality(
         textDirection: TextDirection.ltr,
         child: TextButton(
@@ -731,7 +729,7 @@ void main() {
 
     const List<double> textScaleFactorOptions = <double>[0.5, 1.0, 1.25, 1.5, 2.0, 2.5, 3.0, 4.0];
     const List<TextDirection> textDirectionOptions = <TextDirection>[TextDirection.ltr, TextDirection.rtl];
-    const List<Widget> iconOptions = <Widget>[null, Icon(Icons.add, size: 18, key: iconKey)];
+    const List<Widget?> iconOptions = <Widget?>[null, Icon(Icons.add, size: 18, key: iconKey)];
 
     // Expected values for each textScaleFactor.
     final Map<double, double> paddingVertical = <double, double>{
@@ -781,7 +779,7 @@ void main() {
     }
 
     /// Computes the padding between two [Rect]s, one inside the other.
-    EdgeInsets paddingBetween({ Rect parent, Rect child }) {
+    EdgeInsets paddingBetween({ required Rect parent, required Rect child }) {
       assert (parent.intersect(child) == child);
       return EdgeInsets.fromLTRB(
         child.left - parent.left,
@@ -793,7 +791,7 @@ void main() {
 
     for (final double textScaleFactor in textScaleFactorOptions) {
       for (final TextDirection textDirection in textDirectionOptions) {
-        for (final Widget icon in iconOptions) {
+        for (final Widget? icon in iconOptions) {
           final String testName = 'TextButton'
             ', text scale $textScaleFactor'
             '${icon != null ? ", with icon" : ""}'
@@ -806,7 +804,7 @@ void main() {
                 home: Builder(
                   builder: (BuildContext context) {
                     return MediaQuery(
-                      data: MediaQuery.of(context).copyWith(
+                      data: MediaQuery.of(context)!.copyWith(
                         textScaleFactor: textScaleFactor,
                       ),
                       child: Directionality(
@@ -845,12 +843,12 @@ void main() {
 
             // Compute expected padding, and check.
 
-            final double expectedPaddingTop = paddingVertical[textScaleFactor];
-            final double expectedPaddingBottom = paddingVertical[textScaleFactor];
+            final double expectedPaddingTop = paddingVertical[textScaleFactor]!;
+            final double expectedPaddingBottom = paddingVertical[textScaleFactor]!;
 
             final double expectedPaddingStart = icon != null
-              ? textPaddingWithIconHorizontal[textScaleFactor]
-              : textPaddingWithoutIconHorizontal[textScaleFactor];
+              ? textPaddingWithIconHorizontal[textScaleFactor]!
+              : textPaddingWithoutIconHorizontal[textScaleFactor]!;
             final double expectedPaddingEnd = expectedPaddingStart;
 
             final EdgeInsets expectedPadding = EdgeInsetsDirectional.fromSTEB(
@@ -867,9 +865,9 @@ void main() {
 
             final RenderBox labelRenderBox = tester.renderObject<RenderBox>(find.byKey(labelKey));
             final Rect labelBounds = globalBounds(labelRenderBox);
-            final RenderBox iconRenderBox = icon == null ? null : tester.renderObject<RenderBox>(find.byKey(iconKey));
-            final Rect iconBounds = icon == null ? null : globalBounds(iconRenderBox);
-            final Rect childBounds = icon == null ? labelBounds : labelBounds.expandToInclude(iconBounds);
+            final RenderBox? iconRenderBox = icon == null ? null : tester.renderObject<RenderBox>(find.byKey(iconKey));
+            final Rect? iconBounds = icon == null ? null : globalBounds(iconRenderBox!);
+            final Rect childBounds = icon == null ? labelBounds : labelBounds.expandToInclude(iconBounds!);
 
             // We measure the `InkResponse` descendant of the button
             // element, because the button has a larger `RenderBox`
@@ -918,8 +916,8 @@ void main() {
             // Check the gap between the icon and the label
             if (icon != null) {
               final double gapWidth = textDirection == TextDirection.ltr
-                ? labelBounds.left - iconBounds.right
-                : iconBounds.left - labelBounds.right;
+                ? labelBounds.left - iconBounds!.right
+                : iconBounds!.left - labelBounds.right;
               expect(gapWidth, paddingWithIconGap[textScaleFactor]);
             }
 
@@ -948,7 +946,7 @@ void main() {
         home: Builder(
           builder: (BuildContext context) {
             return MediaQuery(
-              data: MediaQuery.of(context).copyWith(
+              data: MediaQuery.of(context)!.copyWith(
                 textScaleFactor: 2,
               ),
               child: Scaffold(
@@ -978,7 +976,7 @@ void main() {
 }
 
 
-TextStyle _iconStyle(WidgetTester tester, IconData icon) {
+TextStyle? _iconStyle(WidgetTester tester, IconData icon) {
   final RichText iconRichText = tester.widget<RichText>(
     find.descendant(of: find.byIcon(icon), matching: find.byType(RichText)),
   );

packages/flutter/test/material/text_button_theme_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';
@@ -37,10 +35,10 @@ void main() {
     expect(material.elevation, 0.0);
     expect(material.shadowColor, const Color(0xff000000));
     expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4.0)));
-    expect(material.textStyle.color, colorScheme.primary);
-    expect(material.textStyle.fontFamily, 'Roboto');
-    expect(material.textStyle.fontSize, 14);
-    expect(material.textStyle.fontWeight, FontWeight.w500);
+    expect(material.textStyle!.color, colorScheme.primary);
+    expect(material.textStyle!.fontFamily, 'Roboto');
+    expect(material.textStyle!.fontSize, 14);
+    expect(material.textStyle!.fontWeight, FontWeight.w500);
   });
 
   group('[Theme, TextTheme, TextButton style overrides]', () {
@@ -78,7 +76,7 @@ void main() {
       enableFeedback: enableFeedback,
     );
 
-    Widget buildFrame({ ButtonStyle buttonStyle, ButtonStyle themeStyle, ButtonStyle overallStyle }) {
+    Widget buildFrame({ ButtonStyle? buttonStyle, ButtonStyle? themeStyle, ButtonStyle? overallStyle }) {
       final Widget child = Builder(
         builder: (BuildContext context) {
           return TextButton(
@@ -123,15 +121,15 @@ void main() {
     void checkButton(WidgetTester tester) {
       final Material material = tester.widget<Material>(findMaterial);
       final InkWell inkWell = tester.widget<InkWell>(findInkWell);
-      expect(material.textStyle.color, primaryColor);
-      expect(material.textStyle.fontSize, 12);
+      expect(material.textStyle!.color, primaryColor);
+      expect(material.textStyle!.fontSize, 12);
       expect(material.color, backgroundColor);
       expect(material.shadowColor, shadowColor);
       expect(material.elevation, elevation);
-      expect(MaterialStateProperty.resolveAs<MouseCursor>(inkWell.mouseCursor, enabled), enabledMouseCursor);
-      expect(MaterialStateProperty.resolveAs<MouseCursor>(inkWell.mouseCursor, disabled), disabledMouseCursor);
-      expect(inkWell.overlayColor.resolve(hovered), primaryColor.withOpacity(0.04));
-      expect(inkWell.overlayColor.resolve(focused), primaryColor.withOpacity(0.12));
+      expect(MaterialStateProperty.resolveAs<MouseCursor?>(inkWell.mouseCursor, enabled), enabledMouseCursor);
+      expect(MaterialStateProperty.resolveAs<MouseCursor?>(inkWell.mouseCursor, disabled), disabledMouseCursor);
+      expect(inkWell.overlayColor!.resolve(hovered), primaryColor.withOpacity(0.04));
+      expect(inkWell.overlayColor!.resolve(focused), primaryColor.withOpacity(0.12));
       expect(inkWell.enableFeedback, enableFeedback);
       expect(material.borderRadius, null);
       expect(material.shape, shape);
@@ -183,7 +181,7 @@ void main() {
     const Color shadowColor = Color(0xff000001);
     const Color overiddenColor = Color(0xff000002);
 
-    Widget buildFrame({ Color overallShadowColor, Color themeShadowColor, Color shadowColor }) {
+    Widget buildFrame({ Color? overallShadowColor, Color? themeShadowColor, Color? shadowColor }) {
       return MaterialApp(
         theme: ThemeData.from(colorScheme: colorScheme).copyWith(
           shadowColor: overallShadowColor,

packages/flutter/test/material/text_field_focus_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';
 
@@ -40,7 +38,7 @@ void main() {
 
     expect(tester.testTextInput.isVisible, isFalse);
 
-    Navigator.of(tester.element(find.text('Dialog'))).pop();
+    Navigator.of(tester.element(find.text('Dialog')))!.pop();
     await tester.pump();
 
     expect(focusNode.hasPrimaryFocus, isTrue);
@@ -177,7 +175,7 @@ void main() {
   testWidgets('Focus keep-alive works with GlobalKey reparenting', (WidgetTester tester) async {
     final FocusNode focusNode = FocusNode();
 
-    Widget makeTest(String prefix) {
+    Widget makeTest(String? prefix) {
       return MaterialApp(
         home: Material(
           child: ListView(

packages/flutter/test/material/text_field_helper_text_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/material/text_field_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';
@@ -74,7 +72,7 @@ Future<void> restoreAndVerify(WidgetTester tester) async {
 }
 
 class TestWidget extends StatefulWidget {
-  const TestWidget({Key key, this.useExternal = false}) : super(key: key);
+  const TestWidget({Key? key, this.useExternal = false}) : super(key: key);
 
   final bool useExternal;
 
@@ -89,7 +87,7 @@ class TestWidgetState extends State<TestWidget> with RestorationMixin {
   String get restorationId => 'widget';
 
   @override
-  void restoreState(RestorationBucket oldBucket, bool initialRestore) {
+  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
     registerForRestoration(controller, 'controller');
   }
 

packages/flutter/test/material/text_field_splash_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/gestures.dart' show kPressTimeout;
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -14,17 +12,17 @@ bool cancelCalled = false;
 
 class TestInkSplash extends InkSplash {
   TestInkSplash({
-    MaterialInkController controller,
-    RenderBox referenceBox,
-    Offset position,
-    Color color,
+    required MaterialInkController controller,
+    required RenderBox referenceBox,
+    Offset? position,
+    required Color color,
     bool containedInkWell = false,
-    RectCallback rectCallback,
-    BorderRadius borderRadius,
-    ShapeBorder customBorder,
-    double radius,
-    VoidCallback onRemoved,
-    TextDirection textDirection,
+    RectCallback? rectCallback,
+    BorderRadius? borderRadius,
+    ShapeBorder? customBorder,
+    double? radius,
+    VoidCallback? onRemoved,
+    required TextDirection textDirection,
   }) : super(
     controller: controller,
     referenceBox: referenceBox,
@@ -57,17 +55,17 @@ class TestInkSplashFactory extends InteractiveInkFeatureFactory {
 
   @override
   InteractiveInkFeature create({
-    MaterialInkController controller,
-    RenderBox referenceBox,
-    Offset position,
-    Color color,
+    required MaterialInkController controller,
+    required RenderBox referenceBox,
+    Offset? position,
+    required Color color,
     bool containedInkWell = false,
-    RectCallback rectCallback,
-    BorderRadius borderRadius,
-    ShapeBorder customBorder,
-    double radius,
-    VoidCallback onRemoved,
-    TextDirection textDirection,
+    RectCallback? rectCallback,
+    BorderRadius? borderRadius,
+    ShapeBorder? customBorder,
+    double? radius,
+    VoidCallback? onRemoved,
+    required TextDirection textDirection,
   }) {
     return TestInkSplash(
       controller: controller,