[NNBD] Migrate some Cupertino tests (#67086)

packages/flutter/lib/src/cupertino/nav_bar.dart

@@ -344,7 +344,7 @@ class CupertinoNavigationBar extends StatefulWidget implements ObstructingPrefer
   ///
   /// If a border is null, the navigation bar will not display a border.
   /// {@endtemplate}
-  final Border border;
+  final Border? border;
 
   /// {@template flutter.cupertino.navBar.actionsForegroundColor}
   /// Default color used for text and icons of the [leading] and [trailing]
@@ -652,7 +652,7 @@ class CupertinoSliverNavigationBar extends StatefulWidget {
   final EdgeInsetsDirectional? padding;
 
   /// {@macro flutter.cupertino.navBar.border}
-  final Border border;
+  final Border? border;
 
   /// {@macro flutter.cupertino.navBar.actionsForegroundColor}
   ///

packages/flutter/test/cupertino/action_sheet_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/widgets.dart';
 
@@ -63,7 +61,7 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.widgetWithText(DefaultTextStyle, 'Ok'));
 
-    expect(widget.style.color, const CupertinoDynamicColor.withBrightnessAndContrast(
+    expect(widget.style!.color, const CupertinoDynamicColor.withBrightnessAndContrast(
       color: Color.fromARGB(255, 255, 59, 48),
       darkColor: Color.fromARGB(255, 255, 69, 58),
       highContrastColor: Color.fromARGB(255, 215, 0, 21),
@@ -78,7 +76,7 @@ void main() {
     );
 
     Brightness brightness = Brightness.light;
-    StateSetter stateSetter;
+    late StateSetter stateSetter;
 
     TextStyle actionTextStyle(String text) {
       return tester.widget<DefaultTextStyle>(
@@ -86,7 +84,7 @@ void main() {
           of: find.widgetWithText(CupertinoActionSheetAction, text),
           matching: find.byType(DefaultTextStyle),
         ),
-      ).style;
+      ).style!;
     }
 
     await tester.pumpWidget(
@@ -115,7 +113,7 @@ void main() {
     await tester.pump();
 
     expect(
-      actionTextStyle('action').color.value,
+      actionTextStyle('action').color!.value,
       const Color.fromARGB(255, 0, 122, 255).value,
     );
 
@@ -123,7 +121,7 @@ void main() {
     await tester.pump();
 
     expect(
-      actionTextStyle('action').color.value,
+      actionTextStyle('action').color!.value,
       const Color.fromARGB(255, 10, 132, 255).value,
     );
   });
@@ -141,7 +139,7 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.widgetWithText(DefaultTextStyle, 'Ok'));
 
-    expect(widget.style.fontWeight, equals(FontWeight.w600));
+    expect(widget.style!.fontWeight, equals(FontWeight.w600));
   });
 
   testWidgets('Action sheet text styles are correct when both title and message are included', (WidgetTester tester) async {
@@ -162,8 +160,8 @@ void main() {
     final DefaultTextStyle messageStyle = tester.firstWidget(find.widgetWithText(DefaultTextStyle,
         'An action sheet'));
 
-    expect(titleStyle.style.fontWeight, FontWeight.w600);
-    expect(messageStyle.style.fontWeight, FontWeight.w400);
+    expect(titleStyle.style!.fontWeight, FontWeight.w600);
+    expect(messageStyle.style!.fontWeight, FontWeight.w400);
   });
 
   testWidgets('Action sheet text styles are correct when title but no message is included', (WidgetTester tester) async {
@@ -181,7 +179,7 @@ void main() {
     final DefaultTextStyle titleStyle = tester.firstWidget(find.widgetWithText(DefaultTextStyle,
         'Action Sheet'));
 
-    expect(titleStyle.style.fontWeight, FontWeight.w400);
+    expect(titleStyle.style!.fontWeight, FontWeight.w400);
   });
 
   testWidgets('Action sheet text styles are correct when message but no title is included', (WidgetTester tester) async {
@@ -199,7 +197,7 @@ void main() {
     final DefaultTextStyle messageStyle = tester.firstWidget(find.widgetWithText(DefaultTextStyle,
         'An action sheet'));
 
-    expect(messageStyle.style.fontWeight, FontWeight.w600);
+    expect(messageStyle.style!.fontWeight, FontWeight.w600);
   });
 
   testWidgets('Content section but no actions', (WidgetTester tester) async {
@@ -285,7 +283,7 @@ void main() {
       createAppWithButtonThatLaunchesActionSheet(
         Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
             child: CupertinoActionSheet(
               title: const Text('The title'),
               message: const Text('The message.'),
@@ -346,13 +344,13 @@ void main() {
 
   testWidgets('Content section is scrollable', (WidgetTester tester) async {
     final ScrollController messageScrollController = ScrollController();
-    double screenHeight;
+    late double screenHeight;
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesActionSheet(
         Builder(builder: (BuildContext context) {
-          screenHeight = MediaQuery.of(context).size.height;
+          screenHeight = MediaQuery.of(context)!.size.height;
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
             child: CupertinoActionSheet(
               title: const Text('The title'),
               message: Text('Very long content' * 200),

packages/flutter/test/cupertino/activity_indicator_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/scheduler.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -14,18 +12,18 @@ void main() {
   testWidgets('Activity indicator animate property works',
       (WidgetTester tester) async {
     await tester.pumpWidget(buildCupertinoActivityIndicator());
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(1));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(1));
 
     await tester.pumpWidget(buildCupertinoActivityIndicator(false));
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(0));
 
     await tester.pumpWidget(Container());
 
     await tester.pumpWidget(buildCupertinoActivityIndicator(false));
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(0));
 
     await tester.pumpWidget(buildCupertinoActivityIndicator());
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(1));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(1));
   });
 
   testWidgets('Activity indicator dark mode', (WidgetTester tester) async {
@@ -161,7 +159,7 @@ void main() {
   });
 }
 
-Widget buildCupertinoActivityIndicator([bool animating]) {
+Widget buildCupertinoActivityIndicator([bool? animating]) {
   return MediaQuery(
     data: const MediaQueryData(platformBrightness: Brightness.light),
     child: CupertinoActivityIndicator(

packages/flutter/test/cupertino/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_test/flutter_test.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
@@ -52,8 +50,8 @@ void main() {
           builder: (BuildContext context) {
             return Column(
               children: <Widget>[
-                Text(CupertinoLocalizations.of(context).selectAllButtonLabel),
-                Text(CupertinoLocalizations.of(context).datePickerMediumDate(
+                Text(CupertinoLocalizations.of(context)!.selectAllButtonLabel),
+                Text(CupertinoLocalizations.of(context)!.datePickerMediumDate(
                   DateTime(2018, 10, 4),
                 )),
               ],
@@ -126,7 +124,7 @@ void main() {
     expect(find.text('non-regular page one'), findsNothing);
     expect(find.text('regular page one'), findsNothing);
     expect(find.text('regular page two'), findsNothing);
-    navigatorKey.currentState.pop();
+    navigatorKey.currentState!.pop();
     await tester.pumpAndSettle();
     expect(find.text('non-regular page two'), findsNothing);
     expect(find.text('non-regular page one'), findsOneWidget);
@@ -158,7 +156,7 @@ void main() {
     );
     final SimpleNavigatorRouterDelegate delegate = SimpleNavigatorRouterDelegate(
       builder: (BuildContext context, RouteInformation information) {
-        return Text(information.location);
+        return Text(information.location!);
       },
       onPopPage: (Route<void> route, void result, SimpleNavigatorRouterDelegate delegate) {
         delegate.routeInformation = const RouteInformation(
@@ -176,7 +174,7 @@ void main() {
 
     // Simulate android back button intent.
     final ByteData message = const JSONMethodCodec().encodeMethodCall(const MethodCall('popRoute'));
-    await ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage('flutter/navigation', message, (_) { });
+    await ServicesBinding.instance!.defaultBinaryMessenger.handlePlatformMessage('flutter/navigation', message, (_) { });
     await tester.pumpAndSettle();
     expect(find.text('popped'), findsOneWidget);
   });
@@ -201,7 +199,7 @@ class SimpleRouteInformationParser extends RouteInformationParser<RouteInformati
 
 class SimpleNavigatorRouterDelegate extends RouterDelegate<RouteInformation> with PopNavigatorRouterDelegateMixin<RouteInformation>, ChangeNotifier {
   SimpleNavigatorRouterDelegate({
-    @required this.builder,
+    required this.builder,
     this.onPopPage,
   });
 
@@ -209,14 +207,14 @@ class SimpleNavigatorRouterDelegate extends RouterDelegate<RouteInformation> wit
   GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();
 
   RouteInformation get routeInformation => _routeInformation;
-  RouteInformation _routeInformation;
+  late RouteInformation _routeInformation;
   set routeInformation(RouteInformation newValue) {
     _routeInformation = newValue;
     notifyListeners();
   }
 
   SimpleRouterDelegateBuilder builder;
-  SimpleNavigatorRouterDelegatePopPage<void> onPopPage;
+  SimpleNavigatorRouterDelegatePopPage<void>? onPopPage;
 
   @override
   Future<void> setNewRoutePath(RouteInformation configuration) {
@@ -225,7 +223,7 @@ class SimpleNavigatorRouterDelegate extends RouterDelegate<RouteInformation> wit
   }
 
   bool _handlePopPage(Route<void> route, void data) {
-    return onPopPage(route, data, this);
+    return onPopPage!(route, data, this);
   }
 
   @override
@@ -240,7 +238,7 @@ class SimpleNavigatorRouterDelegate extends RouterDelegate<RouteInformation> wit
           child:  Text('base'),
         ),
         CupertinoPage<void>(
-          key: ValueKey<String>(routeInformation?.location),
+          key: ValueKey<String?>(routeInformation.location),
           child: builder(context, routeInformation),
         )
       ],

packages/flutter/test/cupertino/bottom_tab_bar_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:typed_data';
 
 import 'package:flutter/cupertino.dart';
@@ -72,13 +70,13 @@ Future<void> main() async {
       of: find.text('Tab 1'),
       matching: find.byType(RichText),
     ));
-    expect(actualInactive.text.style.color, const Color(0xFF654321));
+    expect(actualInactive.text.style!.color, const Color(0xFF654321));
 
     final RichText actualActive = tester.widget(find.descendant(
       of: find.text('Tab 2'),
       matching: find.byType(RichText),
     ));
-    expect(actualActive.text.style.color, const Color(0xFF123456));
+    expect(actualActive.text.style!.color, const Color(0xFF123456));
   });
 
 
@@ -138,13 +136,13 @@ Future<void> main() async {
       of: find.text('Tab 1'),
       matching: find.byType(RichText),
     ));
-    expect(actualInactive.text.style.color.value, 0xFF000002);
+    expect(actualInactive.text.style!.color!.value, 0xFF000002);
 
     RichText actualActive = tester.widget(find.descendant(
       of: find.text('Tab 2'),
       matching: find.byType(RichText),
     ));
-    expect(actualActive.text.style.color.value, 0xFF000000);
+    expect(actualActive.text.style!.color!.value, 0xFF000000);
 
     final RenderDecoratedBox renderDecoratedBox = tester.renderObject(find.descendant(
       of: find.byType(BackdropFilter),
@@ -153,7 +151,7 @@ Future<void> main() async {
 
     // Border color is resolved correctly.
     final BoxDecoration decoration1 = renderDecoratedBox.decoration as BoxDecoration;
-    expect(decoration1.border.top.color.value, 0x4C000000);
+    expect(decoration1.border!.top.color.value, 0x4C000000);
 
     // Switch to dark mode.
     await pumpWidgetWithBoilerplate(tester, MediaQuery(
@@ -179,17 +177,17 @@ Future<void> main() async {
         of: find.text('Tab 1'),
         matching: find.byType(RichText),
     ));
-    expect(actualInactive.text.style.color.value, 0xFF000003);
+    expect(actualInactive.text.style!.color!.value, 0xFF000003);
 
     actualActive = tester.widget(find.descendant(
         of: find.text('Tab 2'),
         matching: find.byType(RichText),
     ));
-    expect(actualActive.text.style.color.value, 0xFF000001);
+    expect(actualActive.text.style!.color!.value, 0xFF000001);
 
     // Border color is resolved correctly.
     final BoxDecoration decoration2 = renderDecoratedBox.decoration as BoxDecoration;
-    expect(decoration2.border.top.color.value, 0x29000000);
+    expect(decoration2.border!.top.color.value, 0x29000000);
   });
 
   testWidgets('Tabs respects themes', (WidgetTester tester) async {
@@ -215,13 +213,13 @@ Future<void> main() async {
       of: find.text('Tab 1'),
       matching: find.byType(RichText),
     ));
-    expect(actualInactive.text.style.color.value, 0xFF999999);
+    expect(actualInactive.text.style!.color!.value, 0xFF999999);
 
     RichText actualActive = tester.widget(find.descendant(
       of: find.text('Tab 2'),
       matching: find.byType(RichText),
     ));
-    expect(actualActive.text.style.color, CupertinoColors.activeBlue);
+    expect(actualActive.text.style!.color, CupertinoColors.activeBlue);
 
     await tester.pumpWidget(
       CupertinoApp(
@@ -246,14 +244,14 @@ Future<void> main() async {
       of: find.text('Tab 1'),
       matching: find.byType(RichText),
     ));
-    expect(actualInactive.text.style.color.value, 0xFF757575);
+    expect(actualInactive.text.style!.color!.value, 0xFF757575);
 
     actualActive = tester.widget(find.descendant(
       of: find.text('Tab 2'),
       matching: find.byType(RichText),
     ));
 
-    expect(actualActive.text.style.color, isSameColorAs(CupertinoColors.activeBlue.darkColor));
+    expect(actualActive.text.style!.color, isSameColorAs(CupertinoColors.activeBlue.darkColor));
   });
 
   testWidgets('Use active icon', (WidgetTester tester) async {
@@ -368,7 +366,7 @@ Future<void> main() async {
   });
 
   testWidgets('Tap callback', (WidgetTester tester) async {
-    int callbackTab;
+    late int callbackTab;
 
     await pumpWidgetWithBoilerplate(tester, MediaQuery(
       data: const MediaQueryData(),

packages/flutter/test/cupertino/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/rendering.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/scheduler.dart';
@@ -151,11 +149,11 @@ void main() {
 
     expect(value, isFalse);
     // No animating by default.
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(0));
     await tester.tap(find.byType(CupertinoButton));
     expect(value, isTrue);
     // Animates.
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(1));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(1));
   });
 
   testWidgets("Disabled button doesn't animate", (WidgetTester tester) async {
@@ -163,10 +161,10 @@ void main() {
       child: Text('Tap me'),
       onPressed: null,
     )));
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(0));
     await tester.tap(find.byType(CupertinoButton));
     // Still doesn't animate.
-    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
+    expect(SchedulerBinding.instance!.transientCallbackCount, equals(0));
   });
 
   testWidgets('pressedOpacity defaults to 0.1', (WidgetTester tester) async {
@@ -295,7 +293,7 @@ void main() {
       find.widgetWithText(DecoratedBox, 'Skeuomorph me')
     ).decoration as BoxDecoration;
 
-    expect(boxDecoration.color.value, 0xFF654321);
+    expect(boxDecoration.color!.value, 0xFF654321);
 
     await tester.pumpWidget(
       MediaQuery(
@@ -314,18 +312,18 @@ void main() {
     ).decoration as BoxDecoration;
 
     // Disabled color.
-    expect(boxDecoration.color.value, 0xFF111111);
+    expect(boxDecoration.color!.value, 0xFF111111);
   });
 
   testWidgets('Button respects themes', (WidgetTester tester) async {
-    TextStyle textStyle;
+    late TextStyle textStyle;
 
     await tester.pumpWidget(
       CupertinoApp(
         home: CupertinoButton(
           onPressed: () { },
           child: Builder(builder: (BuildContext context) {
-            textStyle = DefaultTextStyle.of(context).style;
+            textStyle = DefaultTextStyle.of(context).style!;
             return const Placeholder();
           }),
         ),
@@ -339,7 +337,7 @@ void main() {
         home: CupertinoButton.filled(
           onPressed: () { },
           child: Builder(builder: (BuildContext context) {
-            textStyle = DefaultTextStyle.of(context).style;
+            textStyle = DefaultTextStyle.of(context).style!;
             return const Placeholder();
           }),
         ),
@@ -361,7 +359,7 @@ void main() {
         home: CupertinoButton(
           onPressed: () { },
           child: Builder(builder: (BuildContext context) {
-            textStyle = DefaultTextStyle.of(context).style;
+            textStyle = DefaultTextStyle.of(context).style!;
             return const Placeholder();
           }),
         ),
@@ -375,7 +373,7 @@ void main() {
         home: CupertinoButton.filled(
           onPressed: () { },
           child: Builder(builder: (BuildContext context) {
-            textStyle = DefaultTextStyle.of(context).style;
+            textStyle = DefaultTextStyle.of(context).style!;
             return const Placeholder();
           }),
         ),
@@ -392,7 +390,7 @@ void main() {
   });
 }
 
-Widget boilerplate({ Widget child }) {
+Widget boilerplate({ required Widget child }) {
   return Directionality(
     textDirection: TextDirection.ltr,
     child: Center(child: child),

packages/flutter/test/cupertino/colors_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/material.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -13,15 +11,15 @@ import '../rendering/mock_canvas.dart';
 
 class DependentWidget extends StatelessWidget {
   const DependentWidget({
-    Key key,
-    this.color,
+    Key? key,
+    required this.color,
   }) : super(key: key);
 
   final Color color;
 
   @override
   Widget build(BuildContext context) {
-    final Color resolved = CupertinoDynamicColor.resolve(color, context, nullOk: false);
+    final Color resolved = CupertinoDynamicColor.resolve(color, context, nullOk: false)!;
     return DecoratedBox(
       decoration: BoxDecoration(color: resolved),
       child: const SizedBox.expand(),
@@ -422,7 +420,7 @@ void main() {
   });
 
   testWidgets('CupertinoDynamicColor used in a CupertinoTheme', (WidgetTester tester) async {
-    CupertinoDynamicColor color;
+    late CupertinoDynamicColor color;
     await tester.pumpWidget(
       CupertinoApp(
         theme: const CupertinoThemeData(
@@ -503,7 +501,7 @@ void main() {
   });
 
   group('MaterialApp:', () {
-    Color color;
+    Color? color;
     setUp(() { color = null; });
 
     testWidgets('dynamic color works in cupertino override theme', (WidgetTester tester) async {

packages/flutter/test/cupertino/context_menu_action_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/cupertino.dart';
 
@@ -15,7 +13,7 @@ void main() {
   const Color _kDestructiveActionColor = CupertinoColors.destructiveRed;
   const FontWeight _kDefaultActionWeight = FontWeight.w600;
 
-  Widget _getApp({VoidCallback onPressed, bool isDestructiveAction = false, bool isDefaultAction = false}) {
+  Widget _getApp({VoidCallback? onPressed, bool isDestructiveAction = false, bool isDefaultAction = false}) {
     final UniqueKey actionKey = UniqueKey();
     final CupertinoContextMenuAction action = CupertinoContextMenuAction(
       key: actionKey,
@@ -52,7 +50,7 @@ void main() {
     );
     expect(finder, findsOneWidget);
     final DefaultTextStyle defaultStyle = tester.widget(finder);
-    return defaultStyle.style;
+    return defaultStyle.style!;
   }
 
   Icon _getIcon(WidgetTester tester) {

packages/flutter/test/cupertino/context_menu_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/cupertino.dart';
 import 'package:flutter/foundation.dart' show kIsWeb;
@@ -24,7 +22,7 @@ void main() {
   Widget _getContextMenu({
     Alignment alignment = Alignment.center,
     Size screenSize = const Size(800.0, 600.0),
-    Widget child,
+    Widget? child,
   }) {
     return CupertinoApp(
       home: CupertinoPageScaffold(

packages/flutter/test/cupertino/dialog_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:math';
 
 import 'package:flutter/cupertino.dart';
@@ -118,7 +116,7 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
-    expect(widget.style.color.withAlpha(255), CupertinoColors.systemRed.color);
+    expect(widget.style!.color!.withAlpha(255), CupertinoColors.systemRed.color);
   });
 
   testWidgets('Dialog dark theme', (WidgetTester tester) async {
@@ -143,7 +141,7 @@ void main() {
     );
 
     expect(
-      cancelText.text.style.color.value,
+      cancelText.text.style!.color!.value,
       0xFF0A84FF, // dark elevated color of systemBlue.
     );
 
@@ -233,7 +231,7 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
-    expect(widget.style.fontWeight, equals(FontWeight.w600));
+    expect(widget.style!.fontWeight, equals(FontWeight.w600));
   });
 
   testWidgets('Dialog default and destructive action styles', (WidgetTester tester) async {
@@ -245,8 +243,8 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
-    expect(widget.style.color.withAlpha(255), CupertinoColors.systemRed.color);
-    expect(widget.style.fontWeight, equals(FontWeight.w600));
+    expect(widget.style!.color!.withAlpha(255), CupertinoColors.systemRed.color);
+    expect(widget.style!.fontWeight, equals(FontWeight.w600));
   });
 
   testWidgets('Dialog disabled action style', (WidgetTester tester) async {
@@ -256,8 +254,8 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
-    expect(widget.style.color.opacity, greaterThanOrEqualTo(127 / 255));
-    expect(widget.style.color.opacity, lessThanOrEqualTo(128 / 255));
+    expect(widget.style!.color!.opacity, greaterThanOrEqualTo(127 / 255));
+    expect(widget.style!.color!.opacity, lessThanOrEqualTo(128 / 255));
   });
 
   testWidgets('Dialog enabled action style', (WidgetTester tester) async {
@@ -268,7 +266,7 @@ void main() {
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
-    expect(widget.style.color.opacity, equals(1.0));
+    expect(widget.style!.color!.opacity, equals(1.0));
   });
 
   testWidgets('Message is scrollable, has correct padding with large text sizes', (WidgetTester tester) async {
@@ -277,7 +275,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
             child: CupertinoAlertDialog(
               title: const Text('The Title'),
               content: Text('Very long content ' * 20),
@@ -377,7 +375,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
             child: CupertinoAlertDialog(
               title: const Text('The title'),
               content: const Text('The content.'),
@@ -438,7 +436,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
             child: CupertinoAlertDialog(
               actions: const <Widget>[
                 CupertinoDialogAction(
@@ -489,7 +487,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
             child: CupertinoAlertDialog(
               title: const Text('The title'),
               content: const Text('The content.'),
@@ -554,11 +552,11 @@ void main() {
 
   testWidgets('Actions section height for 2 side-by-side buttons is height of tallest button.', (WidgetTester tester) async {
     final ScrollController scrollController = ScrollController();
-    double dividerWidth; // Will be set when the dialog builder runs. Needs a BuildContext.
+    late double dividerWidth; // Will be set when the dialog builder runs. Needs a BuildContext.
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
-          dividerWidth = 1.0 / MediaQuery.of(context).devicePixelRatio;
+          dividerWidth = 1.0 / MediaQuery.of(context)!.devicePixelRatio;
           return CupertinoAlertDialog(
             title: const Text('The Title'),
             content: const Text('The message'),
@@ -599,11 +597,11 @@ void main() {
 
   testWidgets('Actions section height for 2 stacked buttons with enough room is height of both buttons.', (WidgetTester tester) async {
     final ScrollController scrollController = ScrollController();
-    double dividerThickness; // Will be set when the dialog builder runs. Needs a BuildContext.
+    late double dividerThickness; // Will be set when the dialog builder runs. Needs a BuildContext.
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
-          dividerThickness = 1.0 / MediaQuery.of(context).devicePixelRatio;
+          dividerThickness = 1.0 / MediaQuery.of(context)!.devicePixelRatio;
           return CupertinoAlertDialog(
             title: const Text('The Title'),
             content: const Text('The message'),
@@ -679,7 +677,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
             child: CupertinoAlertDialog(
               title: const Text('The Title'),
               content: Text('The message\n' * 20),
@@ -807,11 +805,11 @@ void main() {
 
   testWidgets('Pressed button changes appearance and dividers disappear.', (WidgetTester tester) async {
     final ScrollController scrollController = ScrollController();
-    double dividerThickness; // Will be set when the dialog builder runs. Needs a BuildContext.
+    late double dividerThickness; // Will be set when the dialog builder runs. Needs a BuildContext.
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
-          dividerThickness = 1.0 / MediaQuery.of(context).devicePixelRatio;
+          dividerThickness = 1.0 / MediaQuery.of(context)!.devicePixelRatio;
           return CupertinoAlertDialog(
             title: const Text('The Title'),
             content: const Text('The message'),
@@ -1153,7 +1151,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
             child: const RepaintBoundary(
               child: CupertinoAlertDialog(
                 title: Text('Title'),
@@ -1195,7 +1193,9 @@ RenderBox findScrollableActionsSectionRenderBox(WidgetTester tester) {
   return actionsSection as RenderBox;
 }
 
-Widget createAppWithButtonThatLaunchesDialog({ WidgetBuilder dialogBuilder }) {
+Widget createAppWithButtonThatLaunchesDialog({
+  required WidgetBuilder dialogBuilder
+}) {
   return MaterialApp(
     home: Material(
       child: Center(

packages/flutter/test/cupertino/icon_theme_data_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_test/flutter_test.dart';
 
@@ -11,7 +9,7 @@ void main() {
   testWidgets('IconTheme.of works', (WidgetTester tester) async {
     const IconThemeData data = IconThemeData(color: Color(0xAAAAAAAA), opacity: 0.5, size: 16.0);
 
-    IconThemeData retrieved;
+    late IconThemeData retrieved;
     await tester.pumpWidget(
       IconTheme(data: data, child: Builder(builder: (BuildContext context) {
         retrieved = IconTheme.of(context);

packages/flutter/test/cupertino/localizations_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_test/flutter_test.dart';
 

packages/flutter/test/cupertino/nav_bar_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/rendering.dart';
 import 'package:flutter/services.dart';
@@ -394,11 +392,11 @@ void main() {
         ..sort((Element a, Element b) {
           final RenderParagraph aParagraph = a.renderObject as RenderParagraph;
           final RenderParagraph bParagraph = b.renderObject as RenderParagraph;
-          return aParagraph.text.style.fontSize.compareTo(bParagraph.text.style.fontSize);
+          return aParagraph.text.style!.fontSize!.compareTo(bParagraph.text.style!.fontSize!);
         });
 
     Iterable<double> opacities = titles.map<double>((Element element) {
-      final RenderAnimatedOpacity renderOpacity = element.findAncestorRenderObjectOfType<RenderAnimatedOpacity>();
+      final RenderAnimatedOpacity renderOpacity = element.findAncestorRenderObjectOfType<RenderAnimatedOpacity>()!;
       return renderOpacity.opacity.value;
     });
 
@@ -419,11 +417,11 @@ void main() {
         ..sort((Element a, Element b) {
           final RenderParagraph aParagraph = a.renderObject as RenderParagraph;
           final RenderParagraph bParagraph = b.renderObject as RenderParagraph;
-          return aParagraph.text.style.fontSize.compareTo(bParagraph.text.style.fontSize);
+          return aParagraph.text.style!.fontSize!.compareTo(bParagraph.text.style!.fontSize!);
         });
 
     opacities = titles.map<double>((Element element) {
-      final RenderAnimatedOpacity renderOpacity = element.findAncestorRenderObjectOfType<RenderAnimatedOpacity>();
+      final RenderAnimatedOpacity renderOpacity = element.findAncestorRenderObjectOfType<RenderAnimatedOpacity>()!;
       return renderOpacity.opacity.value;
     });
 
@@ -531,7 +529,7 @@ void main() {
     expect(find.text('Different title'), findsOneWidget);
 
     RenderAnimatedOpacity largeTitleOpacity =
-        tester.element(find.text('Title')).findAncestorRenderObjectOfType<RenderAnimatedOpacity>();
+        tester.element(find.text('Title')).findAncestorRenderObjectOfType<RenderAnimatedOpacity>()!;
     // Large title initially visible.
     expect(
       largeTitleOpacity.opacity.value,
@@ -550,7 +548,7 @@ void main() {
     await tester.pump(const Duration(milliseconds: 300));
 
     largeTitleOpacity =
-        tester.element(find.text('Title')).findAncestorRenderObjectOfType<RenderAnimatedOpacity>();
+        tester.element(find.text('Title')).findAncestorRenderObjectOfType<RenderAnimatedOpacity>()!;
     // Large title no longer visible.
     expect(
       largeTitleOpacity.opacity.value,
@@ -680,7 +678,7 @@ void main() {
     final BoxDecoration decoration = decoratedBox.decoration as BoxDecoration;
     expect(decoration.border, isNotNull);
 
-    final BorderSide side = decoration.border.bottom;
+    final BorderSide side = decoration.border!.bottom;
     expect(side, isNotNull);
   });
 
@@ -708,7 +706,7 @@ void main() {
     final BoxDecoration decoration = decoratedBox.decoration as BoxDecoration;
     expect(decoration.border, isNotNull);
 
-    final BorderSide side = decoration.border.bottom;
+    final BorderSide side = decoration.border!.bottom;
     expect(side, isNotNull);
     expect(side.color, const Color(0xFFAABBCC));
   });
@@ -757,7 +755,7 @@ void main() {
     final BoxDecoration decoration = decoratedBox.decoration as BoxDecoration;
     expect(decoration.border, isNotNull);
 
-    final BorderSide bottom = decoration.border.bottom;
+    final BorderSide bottom = decoration.border!.bottom;
     expect(bottom, isNotNull);
   });
 
@@ -863,10 +861,10 @@ void main() {
     final BoxDecoration decoration = decoratedBox.decoration as BoxDecoration;
     expect(decoration.border, isNotNull);
 
-    final BorderSide top = decoration.border.top;
+    final BorderSide top = decoration.border!.top;
     expect(top, isNotNull);
     expect(top, BorderSide.none);
-    final BorderSide bottom = decoration.border.bottom;
+    final BorderSide bottom = decoration.border!.bottom;
     expect(bottom, isNotNull);
     expect(bottom.color, const Color(0xFFAABBCC));
   });
@@ -1108,7 +1106,7 @@ void main() {
       CupertinoApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
+            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
             child: CupertinoPageScaffold(
               child: CustomScrollView(
                 slivers: <Widget>[
@@ -1156,7 +1154,7 @@ void main() {
       title: 'title',
       builder: (BuildContext context) {
         return MediaQuery(
-          data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
+          data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
           child: Container(
             child: const CupertinoPageScaffold(
               child: CustomScrollView(
@@ -1190,14 +1188,17 @@ void main() {
 }
 
 class _ExpectStyles extends StatelessWidget {
-  const _ExpectStyles({ this.color, this.index });
+  const _ExpectStyles({
+    required this.color,
+    required this.index
+  });
 
   final Color color;
   final int index;
 
   @override
   Widget build(BuildContext context) {
-    final TextStyle style = DefaultTextStyle.of(context).style;
+    final TextStyle style = DefaultTextStyle.of(context).style!;
     expect(style.color, isSameColorAs(color));
     expect(style.fontFamily, '.SF Pro Text');
     expect(style.fontSize, 17.0);

packages/flutter/test/cupertino/page_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_test/flutter_test.dart';
 
@@ -276,10 +274,10 @@ void main() {
   testWidgets('test edge swipes work with media query padding (LTR)', (WidgetTester tester) async {
     await tester.pumpWidget(
       CupertinoApp(
-        builder: (BuildContext context, Widget navigator) {
+        builder: (BuildContext context, Widget? navigator) {
           return MediaQuery(
             data: const MediaQueryData(padding: EdgeInsets.only(left: 40)),
-            child: navigator,
+            child: navigator!,
           );
         },
         home: const Placeholder(),
@@ -320,12 +318,12 @@ void main() {
   testWidgets('test edge swipes work with media query padding (RLT)', (WidgetTester tester) async {
     await tester.pumpWidget(
       CupertinoApp(
-        builder: (BuildContext context, Widget navigator) {
+        builder: (BuildContext context, Widget? navigator) {
           return Directionality(
             textDirection: TextDirection.rtl,
             child: MediaQuery(
               data: const MediaQueryData(padding: EdgeInsets.only(right: 40)),
-              child: navigator,
+              child: navigator!,
             ),
           );
         },
@@ -471,7 +469,7 @@ void main() {
     expect(find.text('subpage'), findsOneWidget);
     expect(find.text('home'), findsNothing);
 
-    navigator.currentState.pop();
+    navigator.currentState!.pop();
     await tester.pump();
 
     expect(find.text('subpage'), findsOneWidget);
@@ -498,14 +496,14 @@ class RtlOverrideWidgetsLocalization implements WidgetsLocalizations {
 class KeepsStateTestWidget extends StatefulWidget {
   const KeepsStateTestWidget({this.navigatorKey});
 
-  final Key navigatorKey;
+  final Key? navigatorKey;
 
   @override
   State<KeepsStateTestWidget> createState() => _KeepsStateTestWidgetState();
 }
 
 class _KeepsStateTestWidgetState extends State<KeepsStateTestWidget> {
-  String _subpage = 'subpage';
+  String? _subpage = 'subpage';
 
   @override
   Widget build(BuildContext context) {
@@ -514,7 +512,7 @@ class _KeepsStateTestWidgetState extends State<KeepsStateTestWidget> {
         key: widget.navigatorKey,
         pages: <Page<void>>[
           const CupertinoPage<void>(child: Text('home')),
-          if (_subpage != null) CupertinoPage<void>(child: Text(_subpage)),
+          if (_subpage != null) CupertinoPage<void>(child: Text(_subpage!)),
         ],
         onPopPage: (Route<dynamic> route, dynamic result) {
           if (!route.didPop(result)) {

packages/flutter/test/cupertino/picker_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/rendering.dart';
@@ -39,8 +37,8 @@ void main() {
 
     final RenderParagraph paragraph = tester.renderObject(find.text('1'));
 
-    expect(paragraph.text.style.color, isSameColorAs(CupertinoColors.black));
-    expect(paragraph.text.style.copyWith(color: CupertinoColors.black), const TextStyle(
+    expect(paragraph.text.style!.color, isSameColorAs(CupertinoColors.black));
+    expect(paragraph.text.style!.copyWith(color: CupertinoColors.black), const TextStyle(
       inherit: false,
       fontFamily: '.SF Pro Display',
       fontSize: 21.0,