NNDB TextField tests (#67696)

Just another nnbd conversion PR.

packages/flutter/test/material/text_field_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') // This whole test suite needs triage.
 import 'dart:math' as math;
 import 'dart:ui' as ui show window, BoxHeightStyle, BoxWidthStyle;
@@ -31,7 +29,7 @@ class MockClipboard {
       case 'Clipboard.getData':
         return _clipboardData;
       case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
+        _clipboardData = methodCall.arguments as Object;
         break;
     }
   }
@@ -59,7 +57,7 @@ class WidgetsLocalizationsDelegate extends LocalizationsDelegate<WidgetsLocaliza
   bool shouldReload(WidgetsLocalizationsDelegate old) => false;
 }
 
-Widget overlay({ Widget child }) {
+Widget overlay({ required Widget child }) {
   final OverlayEntry entry = OverlayEntry(
     builder: (BuildContext context) {
       return Center(
@@ -93,7 +91,7 @@ Widget overlayWithEntry(OverlayEntry entry) {
   );
 }
 
-Widget boilerplate({ Widget child }) {
+Widget boilerplate({ required Widget child }) {
   return MaterialApp(
     home: Localizations(
       locale: const Locale('en', 'US'),
@@ -154,8 +152,8 @@ void main() {
 
   final Key textFieldKey = UniqueKey();
   Widget textFieldBuilder({
-    int maxLines = 1,
-    int minLines,
+    int? maxLines = 1,
+    int? minLines,
   }) {
     return boilerplate(
       child: TextField(
@@ -192,7 +190,7 @@ void main() {
 
   testWidgets('TextField has consistent size', (WidgetTester tester) async {
     final Key textFieldKey = UniqueKey();
-    String textFieldValue;
+    late String textFieldValue;
 
     await tester.pumpWidget(
       overlay(
@@ -288,24 +286,24 @@ void main() {
     final EditableTextState editableTextState = tester.firstState(find.byType(EditableText));
     final RenderEditable renderEditable = editableTextState.renderEditable;
 
-    expect(renderEditable.cursorColor.alpha, 255);
+    expect(renderEditable.cursorColor!.alpha, 255);
 
     await tester.pump(const Duration(milliseconds: 100));
     await tester.pump(const Duration(milliseconds: 400));
 
-    expect(renderEditable.cursorColor.alpha, 255);
+    expect(renderEditable.cursorColor!.alpha, 255);
 
     await tester.pump(const Duration(milliseconds: 200));
     await tester.pump(const Duration(milliseconds: 100));
 
-    expect(renderEditable.cursorColor.alpha, 110);
+    expect(renderEditable.cursorColor!.alpha, 110);
 
     await tester.pump(const Duration(milliseconds: 100));
 
-    expect(renderEditable.cursorColor.alpha, 16);
+    expect(renderEditable.cursorColor!.alpha, 16);
     await tester.pump(const Duration(milliseconds: 50));
 
-    expect(renderEditable.cursorColor.alpha, 0);
+    expect(renderEditable.cursorColor!.alpha, 0);
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
 
   testWidgets('Cursor radius is 2.0', (WidgetTester tester) async {
@@ -400,7 +398,7 @@ void main() {
     await expectLater(
       find.byKey(const ValueKey<int>(1)),
       matchesGoldenFile(
-        'text_field_cursor_test_${describeEnum(debugDefaultTargetPlatformOverride).toLowerCase()}.material.1.png',
+        'text_field_cursor_test_${describeEnum(debugDefaultTargetPlatformOverride!).toLowerCase()}.material.1.png',
       ),
     );
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
@@ -812,12 +810,12 @@ void main() {
 
     await tester.pump();
 
-    String editText = findRenderEditable(tester).text.text;
+    String editText = findRenderEditable(tester).text!.text!;
     expect(editText.substring(editText.length - 1), newChar);
 
     await tester.pump(const Duration(seconds: 2));
 
-    editText = findRenderEditable(tester).text.text;
+    editText = findRenderEditable(tester).text!.text!;
     expect(editText.substring(editText.length - 1), '\u2022');
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.android }));
 
@@ -852,7 +850,7 @@ void main() {
 
     await tester.pump();
 
-    final String editText = findRenderEditable(tester).text.text;
+    final String editText = findRenderEditable(tester).text!.text!;
     expect(editText.substring(editText.length - 1), '\u2022');
   }, variant: const TargetPlatformVariant(<TargetPlatform>{
       TargetPlatform.macOS,
@@ -1105,7 +1103,7 @@ void main() {
     expect(tester.testTextInput.hasAnyClients, false);
     final EditableTextState editableText = tester.state(find.byType(EditableText));
     // Collapse selection should not paint.
-    expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
     // Long press on the 'd' character of text 'readOnly' to show context menu.
     const int dIndex = 3;
     final Offset dPos = textOffsetToPosition(tester, dIndex);
@@ -1184,7 +1182,7 @@ void main() {
     await tester.pumpAndSettle();
     final EditableTextState state = tester.state(find.byType(EditableText));
     TextSelection currentOverlaySelection =
-        state.selectionOverlay.value.selection;
+        state.selectionOverlay!.value.selection;
     expect(currentOverlaySelection.baseOffset, 0);
     expect(currentOverlaySelection.extentOffset, 8);
 
@@ -1200,7 +1198,7 @@ void main() {
     entry.markNeedsBuild();
 
     await tester.pump();
-    currentOverlaySelection = state.selectionOverlay.value.selection;
+    currentOverlaySelection = state.selectionOverlay!.value.selection;
     expect(currentOverlaySelection.baseOffset, 1);
     expect(currentOverlaySelection.extentOffset, 7);
   });
@@ -1224,7 +1222,7 @@ void main() {
 
     final RenderEditable renderEditable = findRenderEditable(tester);
     // There should be no composing.
-    expect(renderEditable.text, TextSpan(text:'readonly', style: renderEditable.text.style));
+    expect(renderEditable.text, TextSpan(text:'readonly', style: renderEditable.text!.style));
   });
 
   testWidgets('Dynamically switching between read only and not read only should hide or show collapse cursor', (WidgetTester tester) async {
@@ -1248,18 +1246,18 @@ void main() {
 
     final EditableTextState editableText = tester.state(find.byType(EditableText));
     // Collapse selection should not paint.
-    expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
 
     readOnly = false;
     // Mark entry to be dirty in order to trigger overlay update.
     entry.markNeedsBuild();
     await tester.pumpAndSettle();
-    expect(editableText.selectionOverlay.handlesAreVisible, isTrue);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isTrue);
 
     readOnly = true;
     entry.markNeedsBuild();
     await tester.pumpAndSettle();
-    expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
   });
 
   testWidgets('Dynamically switching to read only should close input connection', (WidgetTester tester) async {
@@ -1854,13 +1852,12 @@ void main() {
 
     // Toolbar should fade in. Starting at 0% opacity.
     final Element target = tester.element(find.text('Select all'));
-    final FadeTransition opacity = target.findAncestorWidgetOfExactType<FadeTransition>();
-    expect(opacity, isNotNull);
+    final FadeTransition opacity = target.findAncestorWidgetOfExactType<FadeTransition>()!;
     expect(opacity.opacity.value, equals(0.0));
 
     // Still fading in.
     await tester.pump(const Duration(milliseconds: 50));
-    final FadeTransition opacity2 = target.findAncestorWidgetOfExactType<FadeTransition>();
+    final FadeTransition opacity2 = target.findAncestorWidgetOfExactType<FadeTransition>()!;
     expect(opacity, same(opacity2));
     expect(opacity.opacity.value, greaterThan(0.0));
     expect(opacity.opacity.value, lessThan(1.0));
@@ -2098,8 +2095,8 @@ void main() {
 
   testWidgets('Multiline text when wrapped in Expanded', (WidgetTester tester) async {
     Widget expandedTextFieldBuilder({
-      int maxLines = 1,
-      int minLines,
+      int? maxLines = 1,
+      int? minLines,
       bool expands = false,
     }) {
       return boilerplate(
@@ -2191,7 +2188,7 @@ void main() {
 
   // Regression test for https://github.com/flutter/flutter/pull/29093
   testWidgets('errorText empty string', (WidgetTester tester) async {
-    Widget textFormFieldBuilder(String errorText) {
+    Widget textFormFieldBuilder(String? errorText) {
       return boilerplate(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
@@ -2240,10 +2237,10 @@ void main() {
     const double padding = 24.0;
 
     Widget containedTextFieldBuilder({
-      Widget counter,
-      String helperText,
-      String labelText,
-      Widget prefix,
+      Widget? counter,
+      String? helperText,
+      String? labelText,
+      Widget? prefix,
     }) {
       return boilerplate(
         child: Container(
@@ -2346,7 +2343,7 @@ void main() {
   testWidgets('Multiline hint text will wrap up to maxLines', (WidgetTester tester) async {
     final Key textFieldKey = UniqueKey();
 
-    Widget builder(int maxLines, final String hintMsg) {
+    Widget builder(int? maxLines, final String hintMsg) {
       return boilerplate(
         child: TextField(
           key: textFieldKey,
@@ -2562,7 +2559,7 @@ void main() {
   });
 
   testWidgets('TextField smoke test', (WidgetTester tester) async {
-    String textFieldValue;
+    late String textFieldValue;
 
     await tester.pumpWidget(
       overlay(
@@ -2591,7 +2588,7 @@ void main() {
 
   testWidgets('TextField with global key', (WidgetTester tester) async {
     final GlobalKey textFieldKey = GlobalKey(debugLabel: 'textFieldKey');
-    String textFieldValue;
+    late String textFieldValue;
 
     await tester.pumpWidget(
       overlay(
@@ -2649,8 +2646,8 @@ void main() {
       ),
     );
     final Text helperText = tester.widget(find.text('helper text'));
-    expect(helperText.style.color, themeData.hintColor);
-    expect(helperText.style.fontSize, Typography.englishLike2014.caption.fontSize);
+    expect(helperText.style!.color, themeData.hintColor);
+    expect(helperText.style!.fontSize, Typography.englishLike2014.caption!.fontSize);
   });
 
   testWidgets('TextField with specified helperStyle', (WidgetTester tester) async {
@@ -2698,8 +2695,8 @@ void main() {
     );
 
     final Text hintText = tester.widget(find.text('Placeholder'));
-    expect(hintText.style.color, themeData.hintColor);
-    expect(hintText.style.fontSize, style.fontSize);
+    expect(hintText.style!.color, themeData.hintColor);
+    expect(hintText.style!.fontSize, style.fontSize);
   });
 
   testWidgets('TextField with specified hintStyle', (WidgetTester tester) async {
@@ -3088,8 +3085,8 @@ void main() {
       text: 'More Text',
     );
 
-    TextEditingController currentController;
-    StateSetter setState;
+    TextEditingController? currentController;
+    late StateSetter setState;
 
     await tester.pumpWidget(
       overlay(
@@ -3106,61 +3103,61 @@ void main() {
     // Initial state with null controller.
     await tester.tap(find.byType(TextField));
     await tester.pump();
-    expect(tester.testTextInput.editingState['text'], isEmpty);
+    expect(tester.testTextInput.editingState!['text'], isEmpty);
 
     // Update the controller from null to controller1.
     setState(() {
       currentController = controller1;
     });
     await tester.pump();
-    expect(tester.testTextInput.editingState['text'], equals('Initial Text'));
+    expect(tester.testTextInput.editingState!['text'], equals('Initial Text'));
 
     // Verify that updates to controller1 are handled.
     controller1.text = 'Updated Text';
     await tester.idle();
-    expect(tester.testTextInput.editingState['text'], equals('Updated Text'));
+    expect(tester.testTextInput.editingState!['text'], equals('Updated Text'));
 
     // Verify that switching from controller1 to controller2 is handled.
     setState(() {
       currentController = controller2;
     });
     await tester.pump();
-    expect(tester.testTextInput.editingState['text'], equals('More Text'));
+    expect(tester.testTextInput.editingState!['text'], equals('More Text'));
 
     // Verify that updates to controller1 are ignored.
     controller1.text = 'Ignored Text';
     await tester.idle();
-    expect(tester.testTextInput.editingState['text'], equals('More Text'));
+    expect(tester.testTextInput.editingState!['text'], equals('More Text'));
 
     // Verify that updates to controller text are handled.
     controller2.text = 'Additional Text';
     await tester.idle();
-    expect(tester.testTextInput.editingState['text'], equals('Additional Text'));
+    expect(tester.testTextInput.editingState!['text'], equals('Additional Text'));
 
     // Verify that updates to controller selection are handled.
     controller2.selection = const TextSelection(baseOffset: 0, extentOffset: 5);
     await tester.idle();
-    expect(tester.testTextInput.editingState['selectionBase'], equals(0));
-    expect(tester.testTextInput.editingState['selectionExtent'], equals(5));
+    expect(tester.testTextInput.editingState!['selectionBase'], equals(0));
+    expect(tester.testTextInput.editingState!['selectionExtent'], equals(5));
 
     // Verify that calling clear() clears the text.
     controller2.clear();
     await tester.idle();
-    expect(tester.testTextInput.editingState['text'], equals(''));
+    expect(tester.testTextInput.editingState!['text'], equals(''));
 
     // Verify that switching from controller2 to null preserves current text.
     controller2.text = 'The Final Cut';
     await tester.idle();
-    expect(tester.testTextInput.editingState['text'], equals('The Final Cut'));
+    expect(tester.testTextInput.editingState!['text'], equals('The Final Cut'));
     setState(() {
       currentController = null;
     });
     await tester.pump();
-    expect(tester.testTextInput.editingState['text'], equals('The Final Cut'));
+    expect(tester.testTextInput.editingState!['text'], equals('The Final Cut'));
 
     // Verify that changes to controller2 are ignored.
     controller2.text = 'Goodbye Cruel World';
-    expect(tester.testTextInput.editingState['text'], equals('The Final Cut'));
+    expect(tester.testTextInput.editingState!['text'], equals('The Final Cut'));
   });
 
   testWidgets('Cannot enter new lines onto single line TextField', (WidgetTester tester) async {
@@ -3482,13 +3479,12 @@ void main() {
     expect(controller.selection.start, lessThanOrEqualTo(0));
     expect(controller.selection.end, lessThanOrEqualTo(0));
 
-    FlutterError error;
+    late FlutterError error;
     try {
       controller.selection = const TextSelection.collapsed(offset: 10);
     } on FlutterError catch (e) {
       error = e;
     } finally {
-      expect(error, isNotNull);
       expect(error.diagnostics.length, 1);
       expect(
         error.toStringDeep(),
@@ -3686,7 +3682,7 @@ void main() {
     expect(textController.text, '0123456789101112');
     expect(find.text('16/10'), findsOneWidget);
     Text counterTextWidget = tester.widget(find.text('16/10'));
-    expect(counterTextWidget.style.color, equals(Colors.deepPurpleAccent));
+    expect(counterTextWidget.style!.color, equals(Colors.deepPurpleAccent));
 
     await tester.enterText(find.byType(TextField), '0123456789');
     await tester.pump();
@@ -3694,7 +3690,7 @@ void main() {
     expect(textController.text, '0123456789');
     expect(find.text('10/10'), findsOneWidget);
     counterTextWidget = tester.widget(find.text('10/10'));
-    expect(counterTextWidget.style.color, isNot(equals(Colors.deepPurpleAccent)));
+    expect(counterTextWidget.style!.color, isNot(equals(Colors.deepPurpleAccent)));
   });
 
   testWidgets('maxLength shows warning when maxLengthEnforced is false with surrogate pairs.', (WidgetTester tester) async {
@@ -3716,7 +3712,7 @@ void main() {
     expect(textController.text, '😆012345678910111');
     expect(find.text('16/10'), findsOneWidget);
     Text counterTextWidget = tester.widget(find.text('16/10'));
-    expect(counterTextWidget.style.color, equals(Colors.deepPurpleAccent));
+    expect(counterTextWidget.style!.color, equals(Colors.deepPurpleAccent));
 
     await tester.enterText(find.byType(TextField), '😆012345678');
     await tester.pump();
@@ -3724,7 +3720,7 @@ void main() {
     expect(textController.text, '😆012345678');
     expect(find.text('10/10'), findsOneWidget);
     counterTextWidget = tester.widget(find.text('10/10'));
-    expect(counterTextWidget.style.color, isNot(equals(Colors.deepPurpleAccent)));
+    expect(counterTextWidget.style!.color, isNot(equals(Colors.deepPurpleAccent)));
   });
 
   testWidgets('maxLength shows warning when maxLengthEnforced is false with grapheme clusters.', (WidgetTester tester) async {
@@ -3746,7 +3742,7 @@ void main() {
     expect(textController.text, '👨‍👩‍👦012345678910111');
     expect(find.text('16/10'), findsOneWidget);
     Text counterTextWidget = tester.widget(find.text('16/10'));
-    expect(counterTextWidget.style.color, equals(Colors.deepPurpleAccent));
+    expect(counterTextWidget.style!.color, equals(Colors.deepPurpleAccent));
 
     await tester.enterText(find.byType(TextField), '👨‍👩‍👦012345678');
     await tester.pump();
@@ -3754,7 +3750,7 @@ void main() {
     expect(textController.text, '👨‍👩‍👦012345678');
     expect(find.text('10/10'), findsOneWidget);
     counterTextWidget = tester.widget(find.text('10/10'));
-    expect(counterTextWidget.style.color, isNot(equals(Colors.deepPurpleAccent)));
+    expect(counterTextWidget.style!.color, isNot(equals(Colors.deepPurpleAccent)));
   });
 
   testWidgets('maxLength limits input with surrogate pairs.', (WidgetTester tester) async {
@@ -3874,7 +3870,7 @@ void main() {
       home: Material(
         child: Center(
             child: TextField(
-              buildCounter: (BuildContext context, { int currentLength, int maxLength, bool isFocused }) {
+              buildCounter: (BuildContext context, { required int currentLength, int? maxLength, required bool isFocused }) {
                 return Text('${currentLength.toString()} of ${maxLength.toString()}');
               },
               maxLength: 10,
@@ -3958,25 +3954,25 @@ void main() {
     await tester.pumpWidget(buildFrame(true, false));
     Text helperWidget = tester.widget(find.text(helperText));
     Text counterWidget = tester.widget(find.text(counterText));
-    expect(helperWidget.style.color, isNot(equals(Colors.transparent)));
-    expect(counterWidget.style.color, isNot(equals(Colors.transparent)));
+    expect(helperWidget.style!.color, isNot(equals(Colors.transparent)));
+    expect(counterWidget.style!.color, isNot(equals(Colors.transparent)));
     await tester.pumpWidget(buildFrame(true, true));
     counterWidget = tester.widget(find.text(counterText));
     Text errorWidget = tester.widget(find.text(errorText));
-    expect(helperWidget.style.color, isNot(equals(Colors.transparent)));
-    expect(errorWidget.style.color, isNot(equals(Colors.transparent)));
+    expect(helperWidget.style!.color, isNot(equals(Colors.transparent)));
+    expect(errorWidget.style!.color, isNot(equals(Colors.transparent)));
 
     // When enabled is false, the helper/error and counter are not visible.
     await tester.pumpWidget(buildFrame(false, false));
     helperWidget = tester.widget(find.text(helperText));
     counterWidget = tester.widget(find.text(counterText));
-    expect(helperWidget.style.color, equals(Colors.transparent));
-    expect(counterWidget.style.color, equals(Colors.transparent));
+    expect(helperWidget.style!.color, equals(Colors.transparent));
+    expect(counterWidget.style!.color, equals(Colors.transparent));
     await tester.pumpWidget(buildFrame(false, true));
     errorWidget = tester.widget(find.text(errorText));
     counterWidget = tester.widget(find.text(counterText));
-    expect(counterWidget.style.color, equals(Colors.transparent));
-    expect(errorWidget.style.color, equals(Colors.transparent));
+    expect(counterWidget.style!.color, equals(Colors.transparent));
+    expect(errorWidget.style!.color, equals(Colors.transparent));
   });
 
   testWidgets('currentValueLength/maxValueLength are in the tree', (WidgetTester tester) async {
@@ -4083,7 +4079,7 @@ void main() {
   });
 
   group('Keyboard Tests', () {
-    TextEditingController controller;
+    late TextEditingController controller;
 
     setUp( () {
       controller = TextEditingController();
@@ -4644,7 +4640,6 @@ void main() {
       ),
     );
 
-
     const String testValue = 'a big house';
     await tester.enterText(find.byType(TextField).first, testValue);
     await tester.idle();
@@ -5170,7 +5165,7 @@ void main() {
 
   testWidgets('TextField change selection with semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
-    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner;
+    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner!;
     final TextEditingController controller = TextEditingController()
       ..text = 'Hello';
     final Key key = UniqueKey();
@@ -5269,7 +5264,7 @@ void main() {
     const String textInTextField = 'Hello';
 
     final SemanticsTester semantics = SemanticsTester(tester);
-    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner;
+    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner!;
     final TextEditingController controller = TextEditingController()
       ..text = textInTextField;
     final Key key = UniqueKey();
@@ -5338,7 +5333,7 @@ void main() {
     const String textInTextField = 'Hello';
 
     final SemanticsTester semantics = SemanticsTester(tester);
-    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner;
+    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner!;
     final TextEditingController controller = TextEditingController()
       ..text = textInTextField;
     final Key key = UniqueKey();
@@ -5444,7 +5439,7 @@ void main() {
       boilerplate(
         child: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(
+            data: MediaQuery.of(context)!.copyWith(
               navigationMode: NavigationMode.directional,
             ),
             child: TextField(
@@ -5465,7 +5460,7 @@ void main() {
       boilerplate(
         child: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context).copyWith(
+            data: MediaQuery.of(context)!.copyWith(
               navigationMode: NavigationMode.directional,
             ),
             child:  TextField(
@@ -5741,8 +5736,8 @@ void main() {
     final Key textField2 = UniqueKey();
     final ScrollController scrollController = ScrollController();
 
-    double minOffset;
-    double maxOffset;
+    double? minOffset;
+    double? maxOffset;
 
     scrollController.addListener(() {
       final double offset = scrollController.offset;
@@ -5814,8 +5809,8 @@ void main() {
     final Key textField2 = UniqueKey();
     final ScrollController scrollController = ScrollController();
 
-    double minOffset;
-    double maxOffset;
+    double? minOffset;
+    double? maxOffset;
 
     scrollController.addListener(() {
       final double offset = scrollController.offset;
@@ -5925,9 +5920,9 @@ void main() {
     // This is a regression test for https://github.com/flutter/flutter/issues/24612
 
     Widget buildFrame({
-      double stepWidth,
-      double cursorWidth,
-      TextAlign textAlign,
+      double? stepWidth,
+      required double cursorWidth,
+      required TextAlign textAlign,
     }) {
       return MaterialApp(
         home: Scaffold(
@@ -5952,7 +5947,7 @@ void main() {
     // A cursor of default size doesn't cause the TextField to increase its
     // width.
     const String text = '1234';
-    double stepWidth = 80.0;
+    double? stepWidth = 80.0;
     await tester.pumpWidget(buildFrame(
       stepWidth: 80.0,
       cursorWidth: 2.0,
@@ -6022,12 +6017,12 @@ void main() {
     // Empty TextStyle is overridden by theme
     await tester.pumpWidget(buildFrame(const TextStyle()));
     EditableText editableText = tester.widget(find.byType(EditableText));
-    expect(editableText.style.color, themeData.textTheme.subtitle1.color);
-    expect(editableText.style.background, themeData.textTheme.subtitle1.background);
-    expect(editableText.style.shadows, themeData.textTheme.subtitle1.shadows);
-    expect(editableText.style.decoration, themeData.textTheme.subtitle1.decoration);
-    expect(editableText.style.locale, themeData.textTheme.subtitle1.locale);
-    expect(editableText.style.wordSpacing, themeData.textTheme.subtitle1.wordSpacing);
+    expect(editableText.style.color, themeData.textTheme.subtitle1!.color);
+    expect(editableText.style.background, themeData.textTheme.subtitle1!.background);
+    expect(editableText.style.shadows, themeData.textTheme.subtitle1!.shadows);
+    expect(editableText.style.decoration, themeData.textTheme.subtitle1!.decoration);
+    expect(editableText.style.locale, themeData.textTheme.subtitle1!.locale);
+    expect(editableText.style.wordSpacing, themeData.textTheme.subtitle1!.wordSpacing);
 
     // Properties set on TextStyle override theme
     const Color setColor = Colors.red;
@@ -7570,8 +7565,8 @@ void main() {
     await tester.pump();
 
     final EditableTextState editableText = tester.state(find.byType(EditableText));
-    expect(editableText.selectionOverlay.handlesAreVisible, isTrue);
-    expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isTrue);
+    expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
   });
 
   testWidgets(
@@ -7592,8 +7587,8 @@ void main() {
       await tester.pump();
 
       final EditableTextState editableText = tester.state(find.byType(EditableText));
-      expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
-      expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
+      expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
+      expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
     },
   );
 
@@ -7615,8 +7610,8 @@ void main() {
     await tester.pump();
 
     final EditableTextState editableText = tester.state(find.byType(EditableText));
-    expect(editableText.selectionOverlay.handlesAreVisible, isTrue);
-    expect(editableText.selectionOverlay.toolbarIsVisible, isTrue);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isTrue);
+    expect(editableText.selectionOverlay!.toolbarIsVisible, isTrue);
   });
 
   testWidgets(
@@ -7637,8 +7632,8 @@ void main() {
       await tester.pump();
 
       final EditableTextState editableText = tester.state(find.byType(EditableText));
-      expect(editableText.selectionOverlay.handlesAreVisible, isTrue);
-      expect(editableText.selectionOverlay.toolbarIsVisible, isTrue);
+      expect(editableText.selectionOverlay!.handlesAreVisible, isTrue);
+      expect(editableText.selectionOverlay!.toolbarIsVisible, isTrue);
     },
   );
 
@@ -7662,8 +7657,8 @@ void main() {
     await tester.pump();
 
     final EditableTextState editableText = tester.state(find.byType(EditableText));
-    expect(editableText.selectionOverlay.handlesAreVisible, isTrue);
-    expect(editableText.selectionOverlay.toolbarIsVisible, isTrue);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isTrue);
+    expect(editableText.selectionOverlay!.toolbarIsVisible, isTrue);
   });
 
   testWidgets(
@@ -7686,8 +7681,8 @@ void main() {
       await tester.pump();
 
       final EditableTextState editableText = tester.state(find.byType(EditableText));
-      expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
-      expect(editableText.selectionOverlay.toolbarIsVisible, isTrue);
+      expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
+      expect(editableText.selectionOverlay!.toolbarIsVisible, isTrue);
     },
   );
 
@@ -7719,8 +7714,8 @@ void main() {
       await tester.pump();
 
       final EditableTextState editableText = tester.state(find.byType(EditableText));
-      expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
-      expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
+      expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
+      expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
     },
   );
 
@@ -7752,8 +7747,8 @@ void main() {
       await tester.pump();
 
       final EditableTextState editableText = tester.state(find.byType(EditableText));
-      expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
-      expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
+      expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
+      expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
     },
   );
 
@@ -7789,8 +7784,8 @@ void main() {
       await tester.pump();
 
       final EditableTextState editableText = tester.state(find.byType(EditableText));
-      expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
-      expect(editableText.selectionOverlay.handlesAreVisible, isFalse);
+      expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
+      expect(editableText.selectionOverlay!.handlesAreVisible, isFalse);
     },
   );
 
@@ -7819,7 +7814,7 @@ void main() {
     await tester.pumpAndSettle();
 
     final EditableTextState state = tester.state(find.byType(EditableText));
-    expect(state.selectionOverlay.handlesAreVisible, isFalse);
+    expect(state.selectionOverlay!.handlesAreVisible, isFalse);
     expect(controller.selection, const TextSelection.collapsed(offset: 0));
 
     if (kIsWeb) {
@@ -7832,7 +7827,7 @@ void main() {
         state.currentTextEditingValue.selection,
         const TextSelection(baseOffset: 2, extentOffset: 7),
       );
-      expect(state.selectionOverlay.handlesAreVisible, isFalse);
+      expect(state.selectionOverlay!.handlesAreVisible, isFalse);
     }
   });
 
@@ -7855,8 +7850,8 @@ void main() {
     await tester.pumpAndSettle();
 
     final EditableTextState editableText = tester.state(find.byType(EditableText));
-    expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
-    expect(editableText.selectionOverlay.handlesAreVisible, isTrue);
+    expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
+    expect(editableText.selectionOverlay!.handlesAreVisible, isTrue);
 
     final RenderEditable renderEditable = findRenderEditable(tester);
     final List<TextSelectionPoint> endpoints = globalize(
@@ -7868,11 +7863,11 @@ void main() {
     // Tap the handle to show the toolbar.
     final Offset handlePos = endpoints[0].point + const Offset(0.0, 1.0);
     await tester.tapAt(handlePos, pointer: 7);
-    expect(editableText.selectionOverlay.toolbarIsVisible, isTrue);
+    expect(editableText.selectionOverlay!.toolbarIsVisible, isTrue);
 
     // Tap the handle again to hide the toolbar.
     await tester.tapAt(handlePos, pointer: 7);
-    expect(editableText.selectionOverlay.toolbarIsVisible, isFalse);
+    expect(editableText.selectionOverlay!.toolbarIsVisible, isFalse);
   });
 
   testWidgets('when TextField would be blocked by keyboard, it is shown with enough space for the selection handle', (WidgetTester tester) async {
@@ -7954,7 +7949,7 @@ void main() {
     });
 
     group('intrinsics', () {
-      Widget _buildTest({ bool isDense }) {
+      Widget _buildTest({ required bool isDense }) {
         return MaterialApp(
           home: Scaffold(
             body: CustomScrollView(
@@ -8099,7 +8094,7 @@ void main() {
               TextField(
                 key: textField2Key,
                 maxLength: 1,
-                buildCounter: (BuildContext context, {int currentLength, bool isFocused, int maxLength}) => null,
+                buildCounter: (BuildContext context, {required int currentLength, required bool isFocused, int? maxLength}) => null,
               ),
             ],
           ),
@@ -8228,7 +8223,7 @@ void main() {
 
     await tester.pump();
 
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.grab);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.grab);
 
     // Test default cursor
     await tester.pumpWidget(
@@ -8246,9 +8241,9 @@ void main() {
       ),
     );
 
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
     await gesture.moveTo(edge);
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
     await gesture.moveTo(center);
 
     // Test default cursor when disabled
@@ -8268,14 +8263,14 @@ void main() {
       ),
     );
 
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
     await gesture.moveTo(edge);
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
     await gesture.moveTo(center);
   });
 
   testWidgets('Caret rtl with changing width', (WidgetTester tester) async {
-    StateSetter setState;
+    late StateSetter setState;
     bool isWide = false;
     const double wideWidth = 300.0;
     const double narrowWidth = 200.0;

packages/flutter/test/material/text_form_field_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/services.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -173,7 +171,7 @@ void main() {
   });
 
   testWidgets('onChanged callbacks are called', (WidgetTester tester) async {
-    String _value;
+    late String _value;
 
     await tester.pumpWidget(
       MaterialApp(
@@ -203,7 +201,7 @@ void main() {
           child: Center(
             child: TextFormField(
               autovalidateMode: AutovalidateMode.always,
-              validator: (String value) {
+              validator: (String? value) {
                 _validateCalled++;
                 return null;
               },
@@ -229,7 +227,7 @@ void main() {
             child: TextFormField(
               enabled: true,
               autovalidateMode: AutovalidateMode.always,
-              validator: (String value) {
+              validator: (String? value) {
                 _validateCalled += 1;
                 return null;
               },
@@ -272,25 +270,25 @@ void main() {
     await tester.pumpWidget(buildFrame(true, false));
     Text helperWidget = tester.widget(find.text(helperText));
     Text counterWidget = tester.widget(find.text(counterText));
-    expect(helperWidget.style.color, isNot(equals(Colors.transparent)));
-    expect(counterWidget.style.color, isNot(equals(Colors.transparent)));
+    expect(helperWidget.style!.color, isNot(equals(Colors.transparent)));
+    expect(counterWidget.style!.color, isNot(equals(Colors.transparent)));
     await tester.pumpWidget(buildFrame(true, true));
     counterWidget = tester.widget(find.text(counterText));
     Text errorWidget = tester.widget(find.text(errorText));
-    expect(helperWidget.style.color, isNot(equals(Colors.transparent)));
-    expect(errorWidget.style.color, isNot(equals(Colors.transparent)));
+    expect(helperWidget.style!.color, isNot(equals(Colors.transparent)));
+    expect(errorWidget.style!.color, isNot(equals(Colors.transparent)));
 
     // When enabled is false, the helper/error and counter are not visible.
     await tester.pumpWidget(buildFrame(false, false));
     helperWidget = tester.widget(find.text(helperText));
     counterWidget = tester.widget(find.text(counterText));
-    expect(helperWidget.style.color, equals(Colors.transparent));
-    expect(counterWidget.style.color, equals(Colors.transparent));
+    expect(helperWidget.style!.color, equals(Colors.transparent));
+    expect(counterWidget.style!.color, equals(Colors.transparent));
     await tester.pumpWidget(buildFrame(false, true));
     errorWidget = tester.widget(find.text(errorText));
     counterWidget = tester.widget(find.text(counterText));
-    expect(counterWidget.style.color, equals(Colors.transparent));
-    expect(errorWidget.style.color, equals(Colors.transparent));
+    expect(counterWidget.style!.color, equals(Colors.transparent));
+    expect(errorWidget.style!.color, equals(Colors.transparent));
   });
 
   testWidgets('passing a buildCounter shows returned widget', (WidgetTester tester) async {
@@ -298,7 +296,7 @@ void main() {
       home: Material(
         child: Center(
             child: TextFormField(
-              buildCounter: (BuildContext context, { int currentLength, int maxLength, bool isFocused }) {
+              buildCounter: (BuildContext context, { int? currentLength, int? maxLength, bool? isFocused }) {
                 return Text('${currentLength.toString()} of ${maxLength.toString()}');
               },
               maxLength: 10,
@@ -434,7 +432,7 @@ void main() {
   testWidgets('onChanged callbacks value and FormFieldState.value are sync', (WidgetTester tester) async {
     bool _called = false;
 
-    FormFieldState<String> state;
+    late FormFieldState<String> state;
 
     await tester.pumpWidget(
       MaterialApp(
@@ -484,7 +482,7 @@ void main() {
           child: Scaffold(
             body: TextFormField(
               autovalidateMode: AutovalidateMode.onUserInteraction,
-              validator: (String value) {
+              validator: (String? value) {
                 _validateCalled++;
                 return null;
               },

packages/flutter/test/material/text_selection_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/rendering.dart';
@@ -21,7 +19,7 @@ class MockClipboard {
       case 'Clipboard.getData':
         return _clipboardData;
       case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
+        _clipboardData = methodCall.arguments as Object;
         break;
     }
   }
@@ -38,9 +36,9 @@ void main() {
 
   group('canSelectAll', () {
     Widget createEditableText({
-      Key key,
-      String text,
-      TextSelection selection,
+      required Key key,
+      String? text,
+      TextSelection? selection,
     }) {
       final TextEditingController controller = TextEditingController(text: text)
         ..selection = selection ?? const TextSelection.collapsed(offset: -1);
@@ -59,7 +57,7 @@ void main() {
     testWidgets('should return false when there is no text', (WidgetTester tester) async {
       final GlobalKey<EditableTextState> key = GlobalKey();
       await tester.pumpWidget(createEditableText(key: key));
-      expect(materialTextSelectionControls.canSelectAll(key.currentState), false);
+      expect(materialTextSelectionControls.canSelectAll(key.currentState!), false);
     });
 
     testWidgets('should return true when there is text and collapsed selection', (WidgetTester tester) async {
@@ -68,7 +66,7 @@ void main() {
         key: key,
         text: '123',
       ));
-      expect(materialTextSelectionControls.canSelectAll(key.currentState), true);
+      expect(materialTextSelectionControls.canSelectAll(key.currentState!), true);
     });
 
     testWidgets('should return true when there is text and partial uncollapsed selection', (WidgetTester tester) async {
@@ -78,7 +76,7 @@ void main() {
         text: '123',
         selection: const TextSelection(baseOffset: 1, extentOffset: 2),
       ));
-      expect(materialTextSelectionControls.canSelectAll(key.currentState), true);
+      expect(materialTextSelectionControls.canSelectAll(key.currentState!), true);
     });
 
     testWidgets('should return false when there is text and full selection', (WidgetTester tester) async {
@@ -88,7 +86,7 @@ void main() {
         text: '123',
         selection: const TextSelection(baseOffset: 0, extentOffset: 3),
       ));
-      expect(materialTextSelectionControls.canSelectAll(key.currentState), false);
+      expect(materialTextSelectionControls.canSelectAll(key.currentState!), false);
     });
   });
 

packages/flutter/test/material/text_selection_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/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
@@ -74,7 +72,7 @@ void main() {
     final EditableTextState editableTextState = tester.firstState(find.byType(EditableText));
     final RenderEditable renderEditable = editableTextState.renderEditable;
     expect(renderEditable.cursorColor, defaultCursorColor);
-    expect(Color(renderEditable.selectionColor.value), defaultSelectionColor);
+    expect(Color(renderEditable.selectionColor!.value), defaultSelectionColor);
 
     // Test the selection handle color.
     await tester.pumpWidget(
@@ -117,7 +115,7 @@ void main() {
     await tester.pumpAndSettle();
     final EditableTextState editableTextState = tester.firstState(find.byType(EditableText));
     final RenderEditable renderEditable = editableTextState.renderEditable;
-    expect(renderEditable.cursorColor, textSelectionTheme.cursorColor.withAlpha(0));
+    expect(renderEditable.cursorColor, textSelectionTheme.cursorColor!.withAlpha(0));
     expect(renderEditable.selectionColor, textSelectionTheme.selectionColor);
 
     // Test the selection handle color.
@@ -170,7 +168,7 @@ void main() {
     await tester.pumpAndSettle();
     final EditableTextState editableTextState = tester.firstState(find.byType(EditableText));
     final RenderEditable renderEditable = editableTextState.renderEditable;
-    expect(renderEditable.cursorColor, widgetTextSelectionTheme.cursorColor.withAlpha(0));
+    expect(renderEditable.cursorColor, widgetTextSelectionTheme.cursorColor!.withAlpha(0));
     expect(renderEditable.selectionColor, widgetTextSelectionTheme.selectionColor);
 
     // Test the selection handle color.