Migrate some tests to null-safety (#67085)

packages/flutter/test/cupertino/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/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
@@ -75,7 +73,7 @@ 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;
 
@@ -90,7 +88,7 @@ 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/cupertino/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/cupertino.dart';
 import 'package:flutter/foundation.dart';
@@ -23,7 +21,7 @@ class MockClipboard {
       case 'Clipboard.getData':
         return _clipboardData;
       case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
+        _clipboardData = methodCall.arguments! as Object;
         break;
     }
   }
@@ -80,14 +78,14 @@ void main() {
       ),
     );
     // Disabled buttons have no opacity change when pressed.
-    return button.pressedOpacity < 1.0;
+    return button.pressedOpacity! < 1.0;
   }
 
   group('canSelectAll', () {
     Widget createEditableText({
-      Key key,
-      String text,
-      TextSelection selection,
+      Key? key,
+      String? text,
+      TextSelection? selection,
     }) {
       final TextEditingController controller = TextEditingController(text: text)
         ..selection = selection ?? const TextSelection.collapsed(offset: -1);
@@ -106,7 +104,7 @@ 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(cupertinoTextSelectionControls.canSelectAll(key.currentState), false);
+      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState!), false);
     });
 
     testWidgets('should return true when there is text and collapsed selection', (WidgetTester tester) async {
@@ -115,7 +113,7 @@ void main() {
         key: key,
         text: '123',
       ));
-      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState), true);
+      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState!), true);
     });
 
     testWidgets('should return false when there is text and partial uncollapsed selection', (WidgetTester tester) async {
@@ -125,7 +123,7 @@ void main() {
         text: '123',
         selection: const TextSelection(baseOffset: 1, extentOffset: 2),
       ));
-      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState), false);
+      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState!), false);
     });
 
     testWidgets('should return false when there is text and full selection', (WidgetTester tester) async {
@@ -135,7 +133,7 @@ void main() {
         text: '123',
         selection: const TextSelection(baseOffset: 0, extentOffset: 3),
       ));
-      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState), false);
+      expect(cupertinoTextSelectionControls.canSelectAll(key.currentState!), false);
     });
   });
 

packages/flutter/test/cupertino/theme_test.dart

@@ -2,16 +2,14 @@
 // 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/painting.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-int buildCount;
-CupertinoThemeData actualTheme;
-IconThemeData actualIconTheme;
+int buildCount = 0;
+CupertinoThemeData? actualTheme;
+IconThemeData? actualIconTheme;
 
 final Widget singletonThemeSubtree = Builder(
   builder: (BuildContext context) {
@@ -29,7 +27,7 @@ Future<CupertinoThemeData> testTheme(WidgetTester tester, CupertinoThemeData the
       child: singletonThemeSubtree,
     ),
   );
-  return actualTheme;
+  return actualTheme!;
 }
 
 Future<IconThemeData> testIconTheme(WidgetTester tester, CupertinoThemeData theme) async {
@@ -39,13 +37,14 @@ Future<IconThemeData> testIconTheme(WidgetTester tester, CupertinoThemeData them
       child: singletonThemeSubtree,
     ),
   );
-  return actualIconTheme;
+  return actualIconTheme!;
 }
 
 void main() {
   setUp(() {
     buildCount = 0;
     actualTheme = null;
+    actualIconTheme = null;
   });
 
   testWidgets('Default theme has defaults', (WidgetTester tester) async {
@@ -150,7 +149,7 @@ void main() {
     final Color darkColor = (await testIconTheme(
       tester,
       themeData.copyWith(brightness: Brightness.dark),
-    )).color;
+    )).color!;
 
     expect(darkColor, isSameColorAs(primaryColor.darkColor));
   });
@@ -207,8 +206,8 @@ void main() {
     );
   });
 
-  Brightness currentBrightness;
-  void colorMatches(Color componentColor, CupertinoDynamicColor expectedDynamicColor) {
+  late Brightness currentBrightness;
+  void colorMatches(Color? componentColor, CupertinoDynamicColor expectedDynamicColor) {
     switch (currentBrightness) {
       case Brightness.light:
         expect(componentColor, isSameColorAs(expectedDynamicColor.color));

packages/flutter/test/flutter_test_alternative.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
-
 // Defines a 'package:test' shim.
 // TODO(ianh): Remove this file once https://github.com/dart-lang/matcher/issues/98 is fixed
 

packages/flutter/test/flutter_test_config.dart

@@ -2,6 +2,4 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 export 'package:flutter_goldens/flutter_goldens.dart' show main;

packages/flutter/test/gestures/gesture_binding_resample_event_on_widget_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
-
 // Logically this file should be part of `gesture_binding_test.dart` but is here
 // due to conflict of `flutter_test` and `package:test`.
 // See https://github.com/dart-lang/matcher/issues/98
@@ -75,10 +73,10 @@ void main() {
       ),
     );
 
-    GestureBinding.instance.resamplingEnabled = true;
+    GestureBinding.instance!.resamplingEnabled = true;
     const Duration kSamplingOffset = Duration(microseconds: -5500);
-    GestureBinding.instance.samplingOffset = kSamplingOffset;
-    ui.window.onPointerDataPacket(packet);
+    GestureBinding.instance!.samplingOffset = kSamplingOffset;
+    ui.window.onPointerDataPacket!(packet);
     expect(events.length, 0);
 
     await tester.pump(const Duration(milliseconds: 7));

packages/flutter/test/gestures/resampler_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:ui';
 
 import 'package:flutter/gestures.dart';

packages/flutter/test/image_data.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
-
 /// A 50x50 blue square png.
 const List<int> kBlueSquarePng = <int>[
   0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49,

packages/flutter/test/painting/alignment_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' as math;
 
 import 'package:flutter/painting.dart';
@@ -110,14 +108,14 @@ void main() {
     final AlignmentGeometry mixed3 = const Alignment(25.0, 42.5).add(const AlignmentDirectional(55.0, 80.0));
 
     for (final TextDirection direction in TextDirection.values) {
-      expect(AlignmentGeometry.lerp(mixed1, mixed2, 0.0).resolve(direction), mixed1.resolve(direction));
-      expect(AlignmentGeometry.lerp(mixed1, mixed2, 1.0).resolve(direction), mixed2.resolve(direction));
-      expect(AlignmentGeometry.lerp(mixed1, mixed2, 0.25).resolve(direction), mixed3.resolve(direction));
+      expect(AlignmentGeometry.lerp(mixed1, mixed2, 0.0)!.resolve(direction), mixed1.resolve(direction));
+      expect(AlignmentGeometry.lerp(mixed1, mixed2, 1.0)!.resolve(direction), mixed2.resolve(direction));
+      expect(AlignmentGeometry.lerp(mixed1, mixed2, 0.25)!.resolve(direction), mixed3.resolve(direction));
     }
   });
 
   test('lerp commutes with resolve', () {
-    final List<AlignmentGeometry> offsets = <AlignmentGeometry>[
+    final List<AlignmentGeometry?> offsets = <AlignmentGeometry?>[
       Alignment.topLeft,
       Alignment.topCenter,
       Alignment.topRight,
@@ -154,19 +152,19 @@ void main() {
 
     for (final TextDirection direction in TextDirection.values) {
       final Alignment defaultValue = AlignmentDirectional.center.resolve(direction);
-      for (final AlignmentGeometry a in offsets) {
+      for (final AlignmentGeometry? a in offsets) {
         final Alignment resolvedA = a?.resolve(direction) ?? defaultValue;
-        for (final AlignmentGeometry b in offsets) {
+        for (final AlignmentGeometry? b in offsets) {
           final Alignment resolvedB = b?.resolve(direction) ?? defaultValue;
-          approxExpect(Alignment.lerp(resolvedA, resolvedB, 0.0), resolvedA);
-          approxExpect(Alignment.lerp(resolvedA, resolvedB, 1.0), resolvedB);
+          approxExpect(Alignment.lerp(resolvedA, resolvedB, 0.0)!, resolvedA);
+          approxExpect(Alignment.lerp(resolvedA, resolvedB, 1.0)!, resolvedB);
           approxExpect((AlignmentGeometry.lerp(a, b, 0.0) ?? defaultValue).resolve(direction), resolvedA);
           approxExpect((AlignmentGeometry.lerp(a, b, 1.0) ?? defaultValue).resolve(direction), resolvedB);
           for (final double t in times) {
             assert(t > 0.0);
             assert(t < 1.0);
             final Alignment value = (AlignmentGeometry.lerp(a, b, t) ?? defaultValue).resolve(direction);
-            approxExpect(value, Alignment.lerp(resolvedA, resolvedB, t));
+            approxExpect(value, Alignment.lerp(resolvedA, resolvedB, t)!);
             final double minDX = math.min(resolvedA.x, resolvedB.x);
             final double maxDX = math.max(resolvedA.x, resolvedB.x);
             final double minDY = math.min(resolvedA.y, resolvedB.y);

packages/flutter/test/painting/beveled_rectangle_border_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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
 

packages/flutter/test/painting/binding_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:ui' as ui;
 
 import 'package:flutter/foundation.dart';
@@ -18,7 +16,7 @@ Future<void> main() async {
   final ui.Image image = await createTestImage();
 
   testWidgets('didHaveMemoryPressure clears imageCache', (WidgetTester tester) async {
-    imageCache.putIfAbsent(1, () => OneFrameImageStreamCompleter(
+    imageCache!.putIfAbsent(1, () => OneFrameImageStreamCompleter(
       Future<ImageInfo>.value(ImageInfo(
         image: image,
         scale: 1.0,
@@ -26,11 +24,11 @@ Future<void> main() async {
     )));
 
     await tester.idle();
-    expect(imageCache.currentSize, 1);
+    expect(imageCache!.currentSize, 1);
     final ByteData message = const JSONMessageCodec().encodeMessage(
-      <String, dynamic>{'type': 'memoryPressure'});
-    await ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage('flutter/system', message, (_) { });
-    expect(imageCache.currentSize, 0);
+      <String, dynamic>{'type': 'memoryPressure'})!;
+    await ServicesBinding.instance!.defaultBinaryMessenger.handlePlatformMessage('flutter/system', message, (_) { });
+    expect(imageCache!.currentSize, 0);
   });
 
   test('evict clears live references', () async {
@@ -71,19 +69,19 @@ class TestBindingBase implements BindingBase {
   }
 
   @override
-  void registerBoolServiceExtension({String name, AsyncValueGetter<bool> getter, AsyncValueSetter<bool> setter}) {}
+  void registerBoolServiceExtension({required String name, required AsyncValueGetter<bool> getter, required AsyncValueSetter<bool> setter}) {}
 
   @override
-  void registerNumericServiceExtension({String name, AsyncValueGetter<double> getter, AsyncValueSetter<double> setter}) {}
+  void registerNumericServiceExtension({required String name, required AsyncValueGetter<double> getter, required AsyncValueSetter<double> setter}) {}
 
   @override
-  void registerServiceExtension({String name, ServiceExtensionCallback callback}) {}
+  void registerServiceExtension({required String name, required ServiceExtensionCallback callback}) {}
 
   @override
-  void registerSignalServiceExtension({String name, AsyncCallback callback}) {}
+  void registerSignalServiceExtension({required String name, required AsyncCallback callback}) {}
 
   @override
-  void registerStringServiceExtension({String name, AsyncValueGetter<String> getter, AsyncValueSetter<String> setter}) {}
+  void registerStringServiceExtension({required String name, required AsyncValueGetter<String> getter, required AsyncValueSetter<String> setter}) {}
 
   @override
   void unlocked() {}

packages/flutter/test/painting/border_radius_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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
 
@@ -365,10 +363,10 @@ void main() {
       bottomLeft: Radius.elliptical(95.0, 105.0), // 50,60 -> 140,150
       bottomRight: Radius.elliptical(60.0, 65.0), // 0,0 -> 120,130
     );
-    expect(BorderRadiusGeometry.lerp(a, b, 0.5).resolve(TextDirection.ltr), ltr);
-    expect(BorderRadiusGeometry.lerp(a, b, 0.5).resolve(TextDirection.rtl), rtl);
-    expect(BorderRadiusGeometry.lerp(a, b, 0.0).resolve(TextDirection.ltr), a);
-    expect(BorderRadiusGeometry.lerp(a, b, 1.0).resolve(TextDirection.rtl), b.resolve(TextDirection.rtl));
+    expect(BorderRadiusGeometry.lerp(a, b, 0.5)!.resolve(TextDirection.ltr), ltr);
+    expect(BorderRadiusGeometry.lerp(a, b, 0.5)!.resolve(TextDirection.rtl), rtl);
+    expect(BorderRadiusGeometry.lerp(a, b, 0.0)!.resolve(TextDirection.ltr), a);
+    expect(BorderRadiusGeometry.lerp(a, b, 1.0)!.resolve(TextDirection.rtl), b.resolve(TextDirection.rtl));
   });
 
   test('BorderRadiusGeometry subtract', () {

packages/flutter/test/painting/border_rtl_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/foundation.dart' show DiagnosticLevel, FlutterError;
 import 'package:flutter/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -77,7 +75,7 @@ void main() {
     expect(BoxBorder.lerp(null, directionalWithTop10, 0.25), const BorderDirectional(top: BorderSide(width: 2.5)));
     expect(BoxBorder.lerp(directionalWithTop10, visualWithTop100, 0.25), const Border(top: BorderSide(width: 32.5)));
     expect(BoxBorder.lerp(visualWithSides10, directionalWithMagentaTop5, 0.25), visualWithSides10At75 + directionalWithMagentaTop5At25);
-    expect(BoxBorder.lerp(visualWithYellowTop5, directionalWithMagentaTop5, 0.25), Border(top: BorderSide(width: 5.0, color: Color.lerp(const Color(0xFFFFFF00), const Color(0xFFFF00FF), 0.25))));
+    expect(BoxBorder.lerp(visualWithYellowTop5, directionalWithMagentaTop5, 0.25), Border(top: BorderSide(width: 5.0, color: Color.lerp(const Color(0xFFFFFF00), const Color(0xFFFF00FF), 0.25)!)));
     expect(BoxBorder.lerp(visualWithSides10, directionalWithSides10, 0.25), visualWithSides10At50);
     expect(BoxBorder.lerp(visualWithYellowTop5, directionalWithSides10, 0.25), visualWithYellowTop5At75 + directionalWithSides10At25);
     expect(() => BoxBorder.lerp(SillyBorder(), const Border(), 0.25), throwsFlutterError);
@@ -89,7 +87,7 @@ void main() {
     expect(BoxBorder.lerp(null, directionalWithTop10, 0.75), const BorderDirectional(top: BorderSide(width: 7.5)));
     expect(BoxBorder.lerp(directionalWithTop10, visualWithTop100, 0.75), const Border(top: BorderSide(width: 77.5)));
     expect(BoxBorder.lerp(visualWithSides10, directionalWithMagentaTop5, 0.75), visualWithSides10At25 + directionalWithMagentaTop5At75);
-    expect(BoxBorder.lerp(visualWithYellowTop5, directionalWithMagentaTop5, 0.75), Border(top: BorderSide(width: 5.0, color: Color.lerp(const Color(0xFFFFFF00), const Color(0xFFFF00FF), 0.75))));
+    expect(BoxBorder.lerp(visualWithYellowTop5, directionalWithMagentaTop5, 0.75), Border(top: BorderSide(width: 5.0, color: Color.lerp(const Color(0xFFFFFF00), const Color(0xFFFF00FF), 0.75)!)));
     expect(BoxBorder.lerp(visualWithSides10, directionalWithSides10, 0.75), directionalWithSides10At50);
     expect(BoxBorder.lerp(visualWithYellowTop5, directionalWithSides10, 0.75), visualWithYellowTop5At25 + directionalWithSides10At75);
     expect(() => BoxBorder.lerp(SillyBorder(), const Border(), 0.75), throwsFlutterError);
@@ -120,7 +118,7 @@ void main() {
   });
 
   test('BoxBorder.lerp throws correct FlutterError message', () {
-    FlutterError error;
+    late FlutterError error;
     try {
       BoxBorder.lerp(SillyBorder(), const Border(), 2.0);
     } on FlutterError catch (e) {
@@ -353,13 +351,6 @@ void main() {
     );
   });
 
-  test('BorderDirectional constructor', () {
-    expect(() => BorderDirectional(top: nonconst(null)), throwsAssertionError);
-    expect(() => BorderDirectional(start: nonconst(null)), throwsAssertionError);
-    expect(() => BorderDirectional(end: nonconst(null)), throwsAssertionError);
-    expect(() => BorderDirectional(bottom: nonconst(null)), throwsAssertionError);
-  });
-
   test('BorderDirectional.merge', () {
     const BorderSide magenta3 = BorderSide(color: Color(0xFFFF00FF), width: 3.0);
     const BorderSide magenta6 = BorderSide(color: Color(0xFFFF00FF), width: 6.0);

packages/flutter/test/painting/border_side_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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
 
@@ -17,9 +15,6 @@ void main() {
         style: BorderStyle.solid,
       ),
     );
-    expect(() => BorderSide(color: nonconst(null)), throwsAssertionError);
-    expect(() => BorderSide(width: nonconst(null)), throwsAssertionError);
-    expect(() => BorderSide(style: nonconst(null)), throwsAssertionError);
     expect(() => BorderSide(width: nonconst(-1.0)), throwsAssertionError);
     expect(
       const BorderSide(width: -0.0),
@@ -56,11 +51,8 @@ void main() {
     expect(      BorderSide.canMerge(none3, BorderSide.none), isTrue);
     expect(      BorderSide.canMerge(none3, side2), isFalse);
     expect(      BorderSide.canMerge(none3, yellowNone), isTrue);
-    expect(() => BorderSide.canMerge(null, null), throwsAssertionError);
-    expect(() => BorderSide.canMerge(null, side2), throwsAssertionError);
     expect(      BorderSide.canMerge(side2, BorderSide.none), isTrue);
     expect(      BorderSide.canMerge(side2, none3), isFalse);
-    expect(() => BorderSide.canMerge(side2, null), throwsAssertionError);
     expect(      BorderSide.canMerge(side2, side3), isTrue);
     expect(      BorderSide.canMerge(side2, yellowNone), isTrue);
     expect(      BorderSide.canMerge(side3, side2), isTrue);
@@ -78,11 +70,8 @@ void main() {
     expect(      BorderSide.merge(none3, BorderSide.none), none3);
     expect(() => BorderSide.merge(none3, side2), throwsAssertionError);
     expect(      BorderSide.merge(none3, yellowNone), none3);
-    expect(() => BorderSide.merge(null, null), throwsAssertionError);
-    expect(() => BorderSide.merge(null, side2), throwsAssertionError);
     expect(      BorderSide.merge(side2, BorderSide.none), side2);
     expect(() => BorderSide.merge(side2, none3), throwsAssertionError);
-    expect(() => BorderSide.merge(side2, null), throwsAssertionError);
     expect(      BorderSide.merge(side2, side3), side5);
     expect(      BorderSide.merge(side2, yellowNone), side2);
     expect(      BorderSide.merge(side3, side2), side5);

packages/flutter/test/painting/border_test.dart

@@ -2,21 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  test('Border constructor', () {
-    expect(() => Border(left: nonconst(null)), throwsAssertionError);
-    expect(() => Border(top: nonconst(null)), throwsAssertionError);
-    expect(() => Border(right: nonconst(null)), throwsAssertionError);
-    expect(() => Border(bottom: nonconst(null)), throwsAssertionError);
-  });
-
   test('Border.uniform constructor', () {
-    expect(() => Border.fromBorderSide(null), throwsAssertionError);
     const BorderSide side = BorderSide();
     const Border border = Border.fromBorderSide(side);
     expect(border.left, same(side));
@@ -26,8 +16,6 @@ void main() {
   });
 
   test('Border.symmetric constructor', () {
-    expect(() => Border.symmetric(vertical: nonconst(null)), throwsAssertionError);
-    expect(() => Border.symmetric(horizontal: nonconst(null)), throwsAssertionError);
     const BorderSide side1 = BorderSide(color: Color(0xFFFFFFFF));
     const BorderSide side2 = BorderSide(color: Color(0xFF000000));
     const Border border = Border.symmetric(vertical: side1, horizontal: side2);

packages/flutter/test/painting/box_decoration_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/painting.dart';
 

packages/flutter/test/painting/box_fit_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/painting.dart';
 
 import '../flutter_test_alternative.dart';

packages/flutter/test/painting/box_painter_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/painting.dart';
 
@@ -26,7 +24,7 @@ void main() {
     expect(BorderSide.lerp(side1, side2, 0.0), equals(side1));
     expect(BorderSide.lerp(side1, side2, 1.0), equals(side2));
     expect(BorderSide.lerp(side1, side2, 0.5), equals(BorderSide(
-      color: Color.lerp(const Color(0xFF000000), const Color(0xFF00FFFF), 0.5),
+      color: Color.lerp(const Color(0xFF000000), const Color(0xFF00FFFF), 0.5)!,
       width: 1.5,
       style: BorderStyle.solid,
     )));
@@ -55,8 +53,8 @@ void main() {
 
   test('Border control test', () {
     final Border border1 = Border.all(width: 4.0);
-    final Border border2 = Border.lerp(null, border1, 0.25);
-    final Border border3 = Border.lerp(border1, null, 0.25);
+    final Border border2 = Border.lerp(null, border1, 0.25)!;
+    final Border border3 = Border.lerp(border1, null, 0.25)!;
 
     expect(border1, hasOneLineDescription);
     expect(border1.hashCode, isNot(equals(border2.hashCode)));
@@ -64,7 +62,7 @@ void main() {
     expect(border2.top.width, equals(1.0));
     expect(border3.bottom.width, equals(3.0));
 
-    final Border border4 = Border.lerp(border2, border3, 0.5);
+    final Border border4 = Border.lerp(border2, border3, 0.5)!;
     expect(border4.left.width, equals(2.0));
   });
 
@@ -90,8 +88,8 @@ void main() {
 
   test('BoxShadow control test', () {
     const BoxShadow shadow1 = BoxShadow(blurRadius: 4.0);
-    final BoxShadow shadow2 = BoxShadow.lerp(null, shadow1, 0.25);
-    final BoxShadow shadow3 = BoxShadow.lerp(shadow1, null, 0.25);
+    final BoxShadow shadow2 = BoxShadow.lerp(null, shadow1, 0.25)!;
+    final BoxShadow shadow3 = BoxShadow.lerp(shadow1, null, 0.25)!;
 
     expect(shadow1, hasOneLineDescription);
     expect(shadow1.hashCode, isNot(equals(shadow2.hashCode)));
@@ -100,14 +98,14 @@ void main() {
     expect(shadow2.blurRadius, equals(1.0));
     expect(shadow3.blurRadius, equals(3.0));
 
-    final BoxShadow shadow4 = BoxShadow.lerp(shadow2, shadow3, 0.5);
+    final BoxShadow shadow4 = BoxShadow.lerp(shadow2, shadow3, 0.5)!;
     expect(shadow4.blurRadius, equals(2.0));
 
     List<BoxShadow> shadowList = BoxShadow.lerpList(
-        <BoxShadow>[shadow2, shadow1], <BoxShadow>[shadow3], 0.5);
+        <BoxShadow>[shadow2, shadow1], <BoxShadow>[shadow3], 0.5)!;
     expect(shadowList, equals(<BoxShadow>[shadow4, shadow1.scale(0.5)]));
     shadowList = BoxShadow.lerpList(
-        <BoxShadow>[shadow2], <BoxShadow>[shadow3, shadow1], 0.5);
+        <BoxShadow>[shadow2], <BoxShadow>[shadow3, shadow1], 0.5)!;
     expect(shadowList, equals(<BoxShadow>[shadow4, shadow1.scale(0.5)]));
   });
 

packages/flutter/test/painting/circle_border_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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
 

packages/flutter/test/painting/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/foundation.dart';
 import 'package:flutter/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -25,7 +23,7 @@ void main() {
 
     expect(color.toColor(), const Color(0xb399816b));
 
-    final HSVColor result = HSVColor.lerp(color, const HSVColor.fromAHSV(0.3, 128.0, 0.7, 0.2), 0.25);
+    final HSVColor result = HSVColor.lerp(color, const HSVColor.fromAHSV(0.3, 128.0, 0.7, 0.2), 0.25)!;
     expect(result.alpha, moreOrLessEquals(0.6));
     expect(result.hue, moreOrLessEquals(53.0));
     expect(result.saturation, greaterThan(0.3999));
@@ -129,7 +127,7 @@ void main() {
     const HSVColor endColor = HSVColor.fromAHSV(1.0, 360.0, 1.0, 1.0);
 
     for (double t = -0.5; t < 1.5; t += 0.1) {
-      output.add(HSVColor.lerp(startColor, endColor, t).toColor());
+      output.add(HSVColor.lerp(startColor, endColor, t)!.toColor());
     }
     final List<Color> expectedColors = <Color>[
       const Color(0xff00ffff),
@@ -162,7 +160,7 @@ void main() {
     const HSVColor endColor = HSVColor.fromAHSV(1.0, 0.0, 1.0, 1.0);
 
     for (double t = -0.1; t < 1.1; t += 0.1) {
-      output.add(HSVColor.lerp(startColor, endColor, t).toColor());
+      output.add(HSVColor.lerp(startColor, endColor, t)!.toColor());
     }
     final List<Color> expectedColors = <Color>[
       const Color(0xffffffff),
@@ -188,7 +186,7 @@ void main() {
     const HSVColor endColor = HSVColor.fromAHSV(1.0, 0.0, 1.0, 1.0);
 
     for (double t = -0.1; t < 1.1; t += 0.1) {
-      output.add(HSVColor.lerp(startColor, endColor, t).toColor());
+      output.add(HSVColor.lerp(startColor, endColor, t)!.toColor());
     }
     final List<Color> expectedColors = <Color>[
       const Color(0xff000000),
@@ -221,7 +219,7 @@ void main() {
 
     expect(color.toColor(), const Color(0xb3b8977a));
 
-    final HSLColor result = HSLColor.lerp(color, const HSLColor.fromAHSL(0.3, 128.0, 0.7, 0.2), 0.25);
+    final HSLColor result = HSLColor.lerp(color, const HSLColor.fromAHSL(0.3, 128.0, 0.7, 0.2), 0.25)!;
     expect(result.alpha, moreOrLessEquals(0.6));
     expect(result.hue, moreOrLessEquals(53.0));
     expect(result.saturation, greaterThan(0.3999));
@@ -324,7 +322,7 @@ void main() {
     const HSLColor endColor = HSLColor.fromAHSL(1.0, 360.0, 0.5, 0.5);
 
     for (double t = -0.5; t < 1.5; t += 0.1) {
-      output.add(HSLColor.lerp(startColor, endColor, t).toColor());
+      output.add(HSLColor.lerp(startColor, endColor, t)!.toColor());
     }
     final List<Color> expectedColors = <Color>[
       const Color(0xff40bfbf),
@@ -357,7 +355,7 @@ void main() {
     const HSLColor endColor = HSLColor.fromAHSL(1.0, 0.0, 1.0, 0.5);
 
     for (double t = -0.1; t < 1.1; t += 0.1) {
-      output.add(HSLColor.lerp(startColor, endColor, t).toColor());
+      output.add(HSLColor.lerp(startColor, endColor, t)!.toColor());
     }
     final List<Color> expectedColors = <Color>[
       const Color(0xff808080),
@@ -383,7 +381,7 @@ void main() {
     const HSLColor endColor = HSLColor.fromAHSL(1.0, 0.0, 0.5, 1.0);
 
     for (double t = -0.1; t < 1.1; t += 0.1) {
-      output.add(HSLColor.lerp(startColor, endColor, t).toColor());
+      output.add(HSLColor.lerp(startColor, endColor, t)!.toColor());
     }
     final List<Color> expectedColors = <Color>[
       const Color(0xff000000),
@@ -438,7 +436,7 @@ void main() {
     expect(valueProperties['blue'], 40);
 
     property = ColorProperty('foo', null);
-    final Map<String, Object> json = property.toJsonMap(const DiagnosticsSerializationDelegate());
+    final Map<String, Object?> json = property.toJsonMap(const DiagnosticsSerializationDelegate());
     expect(json.containsKey('valueProperties'), isFalse);
   });
 

packages/flutter/test/painting/common_matchers.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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';
 

packages/flutter/test/painting/continuous_rectangle_border_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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';

packages/flutter/test/painting/decoration_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 @TestOn('!chrome')
 import 'dart:async';
 import 'dart:ui' as ui show Image, ColorFilter;
@@ -17,13 +15,11 @@ import '../painting/mocks_for_image_cache.dart';
 import '../rendering/rendering_tester.dart';
 
 class TestCanvas implements Canvas {
-  TestCanvas([this.invocations]);
-
-  final List<Invocation> invocations;
+  final List<Invocation> invocations = <Invocation>[];
 
   @override
   void noSuchMethod(Invocation invocation) {
-    invocations?.add(invocation);
+    invocations.add(invocation);
   }
 }
 
@@ -177,7 +173,7 @@ void main() {
   // A reference test would be better.
   test('BoxDecoration backgroundImage clip', () async {
     final ui.Image image = await createTestImage(width: 100, height: 100);
-    void testDecoration({ BoxShape shape = BoxShape.rectangle, BorderRadius borderRadius, bool expectClip }) {
+    void testDecoration({ BoxShape shape = BoxShape.rectangle, BorderRadius? borderRadius, required bool expectClip }) {
       assert(shape != null);
       FakeAsync().run((FakeAsync async) async {
         final DelayedImageProvider imageProvider = DelayedImageProvider(image);
@@ -189,8 +185,7 @@ void main() {
           image: backgroundImage,
         );
 
-        final List<Invocation> invocations = <Invocation>[];
-        final TestCanvas canvas = TestCanvas(invocations);
+        final TestCanvas canvas = TestCanvas();
         const ImageConfiguration imageConfiguration = ImageConfiguration(
             size: Size(100.0, 100.0)
         );
@@ -244,7 +239,7 @@ void main() {
 
     final BoxDecoration boxDecoration = BoxDecoration(image: backgroundImage);
     final BoxPainter boxPainter = boxDecoration.createBoxPainter(() { assert(false); });
-    final TestCanvas canvas = TestCanvas(<Invocation>[]);
+    final TestCanvas canvas = TestCanvas();
     boxPainter.paint(canvas, Offset.zero, const ImageConfiguration(size: Size(100.0, 100.0)));
 
     final Invocation call = canvas.invocations.singleWhere((Invocation call) => call.memberName == #drawImageNine);
@@ -270,8 +265,8 @@ void main() {
     final BoxPainter boxPainter = boxDecoration.createBoxPainter(() {
       assert(false);
     });
-    final TestCanvas canvas = TestCanvas(<Invocation>[]);
-    FlutterError error;
+    final TestCanvas canvas = TestCanvas();
+    late FlutterError error;
     try {
       boxPainter.paint(canvas, Offset.zero, const ImageConfiguration(
           size: Size(100.0, 100.0), textDirection: null));
@@ -297,10 +292,10 @@ void main() {
   });
 
   test('DecorationImage - error listener', () async {
-    String exception;
+    late String exception;
     final DecorationImage backgroundImage = DecorationImage(
       image: const SynchronousErrorTestImageProvider('threw'),
-      onError: (dynamic error, StackTrace stackTrace) {
+      onError: (dynamic error, StackTrace? stackTrace) {
         exception = error as String;
       }
     );
@@ -430,7 +425,7 @@ void main() {
 
   test('paintImage BoxFit.none scale test', () async {
     for (double scale = 1.0; scale <= 4.0; scale += 1.0) {
-      final TestCanvas canvas = TestCanvas(<Invocation>[]);
+      final TestCanvas canvas = TestCanvas();
 
       const Rect outputRect = Rect.fromLTWH(30.0, 30.0, 250.0, 250.0);
       final ui.Image image = await createTestImage(width: 100, height: 100);
@@ -473,7 +468,7 @@ void main() {
 
   test('paintImage BoxFit.scaleDown scale test', () async {
     for (double scale = 1.0; scale <= 4.0; scale += 1.0) {
-      final TestCanvas canvas = TestCanvas(<Invocation>[]);
+      final TestCanvas canvas = TestCanvas();
 
       // container size > scaled image size
       const Rect outputRect = Rect.fromLTWH(30.0, 30.0, 250.0, 250.0);
@@ -516,7 +511,7 @@ void main() {
   });
 
   test('paintImage BoxFit.scaleDown test', () async {
-    final TestCanvas canvas = TestCanvas(<Invocation>[]);
+    final TestCanvas canvas = TestCanvas();
 
     // container height (20 px) < scaled image height (50 px)
     const Rect outputRect = Rect.fromLTWH(30.0, 30.0, 250.0, 20.0);
@@ -569,7 +564,7 @@ void main() {
     ];
 
     for (final BoxFit boxFit in boxFits) {
-      final TestCanvas canvas = TestCanvas(<Invocation>[]);
+      final TestCanvas canvas = TestCanvas();
 
       const Rect outputRect = Rect.fromLTWH(30.0, 30.0, 250.0, 250.0);
       final ui.Image image = await createTestImage(width: 100, height: 100);
@@ -595,18 +590,6 @@ void main() {
     }
   });
 
-  test('scale cannot be null in DecorationImage', () async {
-    final ui.Image image = await createTestImage(width: 100, height: 100);
-    try {
-      DecorationImage(scale: null, image: SynchronousTestImageProvider(image));
-    } on AssertionError catch (error) {
-      expect(error.toString(), contains('scale != null'));
-      expect(error.toString(), contains('is not true'));
-      return;
-    }
-    fail('DecorationImage did not throw AssertionError when scale was null');
-  });
-
   test('DecorationImage scale test', () async {
     final ui.Image image = await createTestImage(width: 100, height: 100);
     final DecorationImage backgroundImage = DecorationImage(
@@ -617,7 +600,7 @@ void main() {
 
     final BoxDecoration boxDecoration = BoxDecoration(image: backgroundImage);
     final BoxPainter boxPainter = boxDecoration.createBoxPainter(() { assert(false); });
-    final TestCanvas canvas = TestCanvas(<Invocation>[]);
+    final TestCanvas canvas = TestCanvas();
     boxPainter.paint(canvas, Offset.zero, const ImageConfiguration(size: Size(100.0, 100.0)));
 
     final Invocation call = canvas.invocations.firstWhere((Invocation call) => call.memberName == #drawImageRect);

packages/flutter/test/painting/edge_insets_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/painting.dart';
 import 'package:flutter_test/flutter_test.dart';