Convert services tests to NNBD (#62694)

This converts the packages/flutter/test/services directory to NNBD, now that the services package is converted.

I changed the signature of checkMessageHandler and checkMockMessageHandler on BinaryMessenger to take a nullable handler, since the tests wanted to check to make sure a handler wasn't set, and that functionality no longer works if the handler is non-nullable.

dev/bots/firebase_testlab.sh

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+set -e
+
 # The tests to run on Firebase Test Lab.
 # Currently, the test consists on building an Android App Bundle and ensuring
 # that the app doesn't crash upon startup.
@@ -26,8 +28,6 @@ devices=(
   "model=griffin,version=24"
 )
 
-set -e
-
 GIT_REVISION=$(git rev-parse HEAD)
 
 DEVICE_FLAG=""
@@ -35,6 +35,12 @@ for device in ${devices[*]}; do
   DEVICE_FLAG+="--device $device "
 done
 
+# If running tests locally, the key env var needs to be set.
+if [[ -z $GCLOUD_FIREBASE_TESTLAB_KEY ]]; then
+  echo "Not running firebase test lab tests because GCLOUD_FIREBASE_TESTLAB_KEY isn't set."
+  exit 0
+fi
+
 # New contributors will not have permissions to run this test - they won't be
 # able to access the service account information. We should just mark the test
 # as passed - it will run fine on post submit, where it will still catch

packages/flutter/lib/src/services/binary_messenger.dart

@@ -48,6 +48,9 @@ abstract class BinaryMessenger {
   ///
   /// This method is useful for tests or test harnesses that want to assert the
   /// handler for the specified channel has not been altered by a previous test.
+  ///
+  /// Passing null for the `handler` returns true if the handler for the
+  /// `channel` is not set.
   bool checkMessageHandler(String channel, MessageHandler? handler);
 
   /// Set a mock callback for intercepting messages from the [send] method on
@@ -69,6 +72,9 @@ abstract class BinaryMessenger {
   /// This method is useful for tests or test harnesses that want to assert the
   /// mock handler for the specified channel has not been altered by a previous
   /// test.
+  ///
+  /// Passing null for the `handler` returns true if the handler for the
+  /// `channel` is not set.
   bool checkMockMessageHandler(String channel, MessageHandler? handler);
 }
 

packages/flutter/lib/src/services/platform_channel.dart

@@ -389,6 +389,9 @@ class MethodChannel {
   ///
   /// This method is useful for tests or test harnesses that want to assert the
   /// handler for the specified channel has not been altered by a previous test.
+  ///
+  /// Passing null for the `handler` returns true if the handler for the channel
+  /// is not set.
   bool checkMethodCallHandler(Future<dynamic> Function(MethodCall call)? handler) => _methodChannelHandlers[this] == handler;
 
   /// Sets a mock callback for intercepting method invocations on this channel.
@@ -422,6 +425,9 @@ class MethodChannel {
   ///
   /// This method is useful for tests or test harnesses that want to assert the
   /// handler for the specified channel has not been altered by a previous test.
+  ///
+  /// Passing null for the `handler` returns true if the handler for the channel
+  /// is not set.
   bool checkMockMethodCallHandler(Future<dynamic> Function(MethodCall call)? handler) => _methodChannelMockHandlers[this] == handler;
 
   Future<ByteData?> _handleAsMethodCall(ByteData? message, Future<dynamic> handler(MethodCall call)) async {

packages/flutter/test/services/asset_bundle_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:convert';
 import 'dart:typed_data';
 
@@ -41,7 +39,7 @@ void main() {
 
     expect(bundle.loadCallCount['one'], 1);
 
-    Object loadException;
+    late Object loadException;
     try {
       await bundle.loadString('foo');
     } catch (e) {
@@ -61,7 +59,7 @@ void main() {
   test('NetworkAssetBundle control test', () async {
     final Uri uri = Uri.http('example.org', '/path');
     final NetworkAssetBundle bundle = NetworkAssetBundle(uri);
-    FlutterError error;
+    late FlutterError error;
     try {
       await bundle.load('key');
     } on FlutterError catch (e) {

packages/flutter/test/services/autofill_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:convert' show utf8;
 
 import 'package:flutter/services.dart';
@@ -13,13 +11,12 @@ void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('TextInput message channels', () {
-    FakeTextChannel fakeTextChannel;
-    FakeAutofillScope scope;
+    late FakeTextChannel fakeTextChannel;
+    final FakeAutofillScope scope = FakeAutofillScope();
 
     setUp(() {
       fakeTextChannel = FakeTextChannel((MethodCall call) async {});
       TextInput.setChannel(fakeTextChannel);
-      scope ??= FakeAutofillScope();
       scope.clients.clear();
     });
 
@@ -28,35 +25,8 @@ void main() {
       TextInput.setChannel(SystemChannels.textInput);
     });
 
-    test('mandatory fields are mandatory', () async {
-      AutofillConfiguration config;
-      try {
-        config = AutofillConfiguration(
-          uniqueIdentifier: null,
-          autofillHints: const <String>['test'],
-          currentEditingValue: const TextEditingValue(),
-        );
-      } catch (e) {
-        expect(e.toString(), contains('uniqueIdentifier != null'));
-      }
-
-      expect(config, isNull);
-
-      try {
-        config = AutofillConfiguration(
-          uniqueIdentifier: 'id',
-          autofillHints: null,
-          currentEditingValue: const TextEditingValue(),
-        );
-      } catch (e) {
-        expect(e.toString(), contains('autofillHints != null'));
-      }
-
-      expect(config, isNull);
-    });
-
     test('throws if the hint list is empty', () async {
-      Map<String, dynamic> json;
+      Map<String, dynamic>? json;
       try {
         const AutofillConfiguration config = AutofillConfiguration(
           uniqueIdentifier: 'id',
@@ -113,7 +83,7 @@ void main() {
         ]);
 
         const TextEditingValue text2 = TextEditingValue(text: 'Text 2');
-        fakeTextChannel.incoming(MethodCall(
+        fakeTextChannel.incoming?.call(MethodCall(
           'TextInputClient.updateEditingStateWithTag',
           <dynamic>[0, <String, dynamic>{ client2.autofillId : text2.toJSON() }],
         ));
@@ -130,7 +100,7 @@ class FakeAutofillClient implements TextInputClient, AutofillClient {
   String get autofillId => hashCode.toString();
 
   @override
-  TextInputConfiguration textInputConfiguration;
+  late TextInputConfiguration textInputConfiguration;
 
   @override
   void updateEditingValue(TextEditingValue newEditingValue) {
@@ -139,7 +109,7 @@ class FakeAutofillClient implements TextInputClient, AutofillClient {
   }
 
   @override
-  AutofillScope currentAutofillScope;
+  AutofillScope? currentAutofillScope;
 
   String latestMethodCall = '';
 
@@ -179,7 +149,7 @@ class FakeAutofillScope with AutofillScopeMixin implements AutofillScope {
   Iterable<AutofillClient> get autofillClients => clients.values;
 
   @override
-  AutofillClient getAutofillClient(String autofillId) => clients[autofillId];
+  AutofillClient getAutofillClient(String autofillId) => clients[autofillId]!;
 
   void register(AutofillClient client) {
     clients.putIfAbsent(client.autofillId, () => client);
@@ -190,7 +160,7 @@ class FakeTextChannel implements MethodChannel {
   FakeTextChannel(this.outgoing) : assert(outgoing != null);
 
   Future<dynamic> Function(MethodCall) outgoing;
-  Future<void> Function(MethodCall) incoming;
+  Future<void> Function(MethodCall)? incoming;
 
   List<MethodCall> outgoingCalls = <MethodCall>[];
 
@@ -217,18 +187,18 @@ class FakeTextChannel implements MethodChannel {
   String get name => 'flutter/textinput';
 
   @override
-  void setMethodCallHandler(Future<void> Function(MethodCall call) handler) {
+  void setMethodCallHandler(Future<void> Function(MethodCall call)? handler) {
     incoming = handler;
   }
 
   @override
-  bool checkMethodCallHandler(Future<void> Function(MethodCall call) handler) => throw UnimplementedError();
+  bool checkMethodCallHandler(Future<void> Function(MethodCall call)? handler) => throw UnimplementedError();
 
   @override
-  void setMockMethodCallHandler(Future<void> Function(MethodCall call) handler)  => throw UnimplementedError();
+  void setMockMethodCallHandler(Future<void> Function(MethodCall call)? handler)  => throw UnimplementedError();
 
   @override
-  bool checkMockMethodCallHandler(Future<void> Function(MethodCall call) handler) => throw UnimplementedError();
+  bool checkMockMethodCallHandler(Future<void> Function(MethodCall call)? handler) => throw UnimplementedError();
 
   void validateOutgoingMethodCalls(List<MethodCall> calls) {
     expect(outgoingCalls.length, calls.length);

packages/flutter/test/services/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:typed_data';
 
 import 'package:flutter/foundation.dart';
@@ -45,7 +43,7 @@ class TestBinding extends BindingBase with SchedulerBinding, ServicesBinding {
   @override
   BinaryMessenger createBinaryMessenger() {
     return super.createBinaryMessenger()
-      ..setMockMessageHandler('flutter/assets', (ByteData message) async {
+      ..setMockMessageHandler('flutter/assets', (ByteData? message) async {
         if (const StringCodec().decodeMessage(message) == 'NOTICES') {
           return const StringCodec().encodeMessage(licenses);
         }

packages/flutter/test/services/channel_buffers_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
-
 // TODO(yjbanov): enable Web when https://github.com/flutter/engine/pull/12747 rolls into the framework.
 @TestOn('!chrome')
 
@@ -35,15 +33,15 @@ void main() {
     final TestChannelBuffersFlutterBinding binding = TestChannelBuffersFlutterBinding();
     expect(binding.defaultBinaryMessenger, isNotNull);
     bool didCallCallback = false;
-    final ui.PlatformMessageResponseCallback callback = (ByteData responseData) {
+    final ui.PlatformMessageResponseCallback callback = (ByteData? responseData) {
       didCallCallback = true;
     };
     const String payload = 'bar';
     final ByteData data = _makeByteData(payload);
     ui.channelBuffers.push(channel, data, callback);
     bool didDrainData = false;
-    binding.defaultBinaryMessenger.setMessageHandler(channel, (ByteData message) async {
-      expect(_getString(message), payload);
+    binding.defaultBinaryMessenger.setMessageHandler(channel, (ByteData? message) async {
+      expect(_getString(message!), payload);
       didDrainData = true;
       return null;
     });

packages/flutter/test/services/default_binary_messenger_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:convert';
 import 'dart:typed_data';
 import 'dart:ui' as ui;
@@ -23,22 +21,21 @@ void main() {
   test('default binary messenger calls callback once', () async {
     int count = 0;
     const String channel = 'foo';
-    ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage(
-        channel, _makeByteData('bar'), (ByteData message) async {
+    ServicesBinding.instance!.defaultBinaryMessenger.handlePlatformMessage(
+        channel, _makeByteData('bar'), (ByteData? message) async {
       count += 1;
     });
     expect(count, equals(0));
     await ui.channelBuffers.drain(channel,
-        (ByteData data, ui.PlatformMessageResponseCallback callback) {
+        (ByteData? data, ui.PlatformMessageResponseCallback callback) async {
       callback(null);
-      return null;
     });
     expect(count, equals(1));
   });
 
   test('can check the handler', () {
-    Future<ByteData> handler(ByteData call) => Future<ByteData>.value(null);
-    final BinaryMessenger messenger = ServicesBinding.instance.defaultBinaryMessenger;
+    Future<ByteData> handler(ByteData? call) => Future<ByteData>.value(null);
+    final BinaryMessenger messenger = ServicesBinding.instance!.defaultBinaryMessenger;
 
     expect(messenger.checkMessageHandler('test_channel', null), true);
     expect(messenger.checkMessageHandler('test_channel', handler), false);
@@ -48,8 +45,8 @@ void main() {
   });
 
   test('can check the mock handler', () {
-    Future<ByteData> handler(ByteData call) => Future<ByteData>.value(null);
-    final BinaryMessenger messenger = ServicesBinding.instance.defaultBinaryMessenger;
+    Future<ByteData> handler(ByteData? call) => Future<ByteData>.value(null);
+    final BinaryMessenger messenger = ServicesBinding.instance!.defaultBinaryMessenger;
 
     expect(messenger.checkMockMessageHandler('test_channel', null), true);
     expect(messenger.checkMockMessageHandler('test_channel', handler), false);

packages/flutter/test/services/fake_platform_views.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 import 'dart:typed_data';
 
@@ -14,10 +12,7 @@ import 'package:flutter/widgets.dart';
 
 /// Used in internal testing.
 class FakePlatformViewController extends PlatformViewController {
-
-  FakePlatformViewController(int id) {
-    _id = id;
-  }
+  FakePlatformViewController(this.viewId);
 
   bool disposed = false;
   bool focusCleared = false;
@@ -25,10 +20,8 @@ class FakePlatformViewController extends PlatformViewController {
   /// Events that are dispatched.
   List<PointerEvent> dispatchedPointerEvents = <PointerEvent>[];
 
-  int _id;
-
   @override
-  int get viewId => _id;
+  final int viewId;
 
   @override
   Future<void> dispatchPointerEvent(PointerEvent event) async {
@@ -66,7 +59,7 @@ class FakeAndroidViewController implements AndroidViewController {
   final int viewId;
 
   @override
-  Offset Function(Offset position) pointTransformer;
+  Offset Function(Offset position)? pointTransformer;
 
   @override
   Future<void> dispatchPointerEvent(PointerEvent event) async {
@@ -98,7 +91,7 @@ class FakeAndroidViewController implements AndroidViewController {
   int get textureId => throw UnimplementedError();
 
   @override
-  bool isCreated;
+  bool get isCreated => throw UnimplementedError();
 
   @override
   void addOnPlatformViewCreatedListener(PlatformViewCreatedCallback listener) =>
@@ -133,7 +126,6 @@ class FakeAndroidPlatformViewsController {
     SystemChannels.platform_views.setMockMethodCallHandler(_onMethodCall);
   }
 
-
   Iterable<FakeAndroidPlatformView> get views => _views.values;
   final Map<int, FakeAndroidPlatformView> _views = <int, FakeAndroidPlatformView>{};
 
@@ -143,11 +135,11 @@ class FakeAndroidPlatformViewsController {
 
   int _textureCounter = 0;
 
-  Completer<void> resizeCompleter;
+  Completer<void>? resizeCompleter;
 
-  Completer<void> createCompleter;
+  Completer<void>? createCompleter;
 
-  int lastClearedFocusViewId;
+  int? lastClearedFocusViewId;
 
   void registerViewType(String viewType) {
     _registeredViewTypes.add(viewType);
@@ -156,7 +148,8 @@ class FakeAndroidPlatformViewsController {
   void invokeViewFocused(int viewId) {
     final MethodCodec codec = SystemChannels.platform_views.codec;
     final ByteData data = codec.encodeMethodCall(MethodCall('viewFocused', viewId));
-    ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage(SystemChannels.platform_views.name, data, (ByteData data) {});
+    ServicesBinding.instance!.defaultBinaryMessenger
+        .handlePlatformMessage(SystemChannels.platform_views.name, data, (ByteData? data) {});
   }
 
   Future<dynamic> _onMethodCall(MethodCall call) {
@@ -200,7 +193,7 @@ class FakeAndroidPlatformViewsController {
       );
 
     if (createCompleter != null) {
-      await createCompleter.future;
+      await createCompleter!.future;
     }
 
     _views[id] = FakeAndroidPlatformView(id, viewType,
@@ -219,9 +212,9 @@ class FakeAndroidPlatformViewsController {
     final int id = call.arguments['id'] as int;
     final bool hybrid = call.arguments['hybrid'] as bool;
 
-    if (hybrid && !_views[id].hybrid) {
+    if (hybrid && !_views[id]!.hybrid!) {
       throw ArgumentError('An $AndroidViewController using hybrid composition must pass `hybrid: true`');
-    } else if (!hybrid && _views[id].hybrid != null && _views[id].hybrid) {
+    } else if (!hybrid && (_views[id]!.hybrid ?? false)) {
       throw ArgumentError('An $AndroidViewController not using hybrid composition must pass `hybrid: false`');
     }
 
@@ -248,9 +241,9 @@ class FakeAndroidPlatformViewsController {
       );
 
     if (resizeCompleter != null) {
-      await resizeCompleter.future;
+      await resizeCompleter!.future;
     }
-    _views[id] = _views[id].copyWith(size: Size(width, height));
+    _views[id] = _views[id]!.copyWith(size: Size(width, height));
 
     return Future<dynamic>.sync(() => null);
   }
@@ -273,7 +266,7 @@ class FakeAndroidPlatformViewsController {
     if (!motionEvents.containsKey(id))
       motionEvents[id] = <FakeAndroidMotionEvent> [];
 
-    motionEvents[id].add(FakeAndroidMotionEvent(action, pointerIds, pointerOffsets));
+    motionEvents[id]!.add(FakeAndroidMotionEvent(action, pointerIds, pointerOffsets));
     return Future<dynamic>.sync(() => null);
   }
 
@@ -288,7 +281,7 @@ class FakeAndroidPlatformViewsController {
         message: 'Trying to resize a platform view with unknown id: $id',
       );
 
-    _views[id] = _views[id].copyWith(layoutDirection: layoutDirection);
+    _views[id] = _views[id]!.copyWith(layoutDirection: layoutDirection);
 
     return Future<dynamic>.sync(() => null);
   }
@@ -312,7 +305,6 @@ class FakeIosPlatformViewsController {
     SystemChannels.platform_views.setMockMethodCallHandler(_onMethodCall);
   }
 
-
   Iterable<FakeUiKitView> get views => _views.values;
   final Map<int, FakeUiKitView> _views = <int, FakeUiKitView>{};
 
@@ -320,7 +312,7 @@ class FakeIosPlatformViewsController {
 
   // When this completer is non null, the 'create' method channel call will be
   // delayed until it completes.
-  Completer<void> creationDelay;
+  Completer<void>? creationDelay;
 
   // Maps a view id to the number of gestures it accepted so far.
   final Map<int, int> gesturesAccepted = <int, int>{};
@@ -348,7 +340,7 @@ class FakeIosPlatformViewsController {
 
   Future<dynamic> _create(MethodCall call) async {
     if (creationDelay != null)
-      await creationDelay.future;
+      await creationDelay!.future;
     final Map<dynamic, dynamic> args = call.arguments as Map<dynamic, dynamic>;
     final int id = args['id'] as int;
     final String viewType = args['viewType'] as String;
@@ -371,21 +363,21 @@ class FakeIosPlatformViewsController {
     _views[id] = FakeUiKitView(id, viewType, creationParams);
     gesturesAccepted[id] = 0;
     gesturesRejected[id] = 0;
-    return Future<int>.sync(() => null);
+    return Future<int?>.sync(() => null);
   }
 
   Future<dynamic> _acceptGesture(MethodCall call) async {
     final Map<dynamic, dynamic> args = call.arguments as Map<dynamic, dynamic>;
     final int id = args['id'] as int;
-    gesturesAccepted[id] += 1;
-    return Future<int>.sync(() => null);
+    gesturesAccepted[id] = gesturesAccepted[id]! + 1;
+    return Future<int?>.sync(() => null);
   }
 
   Future<dynamic> _rejectGesture(MethodCall call) async {
     final Map<dynamic, dynamic> args = call.arguments as Map<dynamic, dynamic>;
     final int id = args['id'] as int;
-    gesturesRejected[id] += 1;
-    return Future<int>.sync(() => null);
+    gesturesRejected[id] = gesturesRejected[id]! + 1;
+    return Future<int?>.sync(() => null);
   }
 
   Future<dynamic> _dispose(MethodCall call) {
@@ -413,9 +405,9 @@ class FakeHtmlPlatformViewsController {
 
   final Set<String> _registeredViewTypes = <String>{};
 
-  Completer<void> resizeCompleter;
+  late Completer<void> resizeCompleter;
 
-  Completer<void> createCompleter;
+  Completer<void>? createCompleter;
 
   void registerViewType(String viewType) {
     _registeredViewTypes.add(viewType);
@@ -449,11 +441,11 @@ class FakeHtmlPlatformViewsController {
       );
 
     if (createCompleter != null) {
-      await createCompleter.future;
+      await createCompleter!.future;
     }
 
     _views[id] = FakeHtmlPlatformView(id, viewType);
-    return Future<int>.sync(() => null);
+    return Future<int?>.sync(() => null);
   }
 
   Future<dynamic> _dispose(MethodCall call) {
@@ -476,12 +468,12 @@ class FakeAndroidPlatformView {
 
   final int id;
   final String type;
-  final Uint8List creationParams;
-  final Size size;
+  final Uint8List? creationParams;
+  final Size? size;
   final int layoutDirection;
-  final bool hybrid;
+  final bool? hybrid;
 
-  FakeAndroidPlatformView copyWith({Size size, int layoutDirection}) => FakeAndroidPlatformView(
+  FakeAndroidPlatformView copyWith({Size? size, int? layoutDirection}) => FakeAndroidPlatformView(
     id,
     type,
     size ?? this.size,
@@ -544,7 +536,7 @@ class FakeUiKitView {
 
   final int id;
   final String type;
-  final Uint8List creationParams;
+  final Uint8List? creationParams;
 
   @override
   bool operator ==(Object other) {

packages/flutter/test/services/font_loader_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/services.dart';

packages/flutter/test/services/haptic_feedback_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/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 

packages/flutter/test/services/keyboard_key_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/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 

packages/flutter/test/services/lifecycle_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/services.dart';
 
@@ -11,7 +9,7 @@ void main() {
   testWidgets('initialLifecycleState is used to init state paused', (WidgetTester tester) async {
     // The lifecycleState is null initially in tests as there is no
     // initialLifecycleState.
-    expect(ServicesBinding.instance.lifecycleState, equals(null));
+    expect(ServicesBinding.instance!.lifecycleState, equals(null));
     // Mock the Window to provide paused as the AppLifecycleState
     final TestWidgetsFlutterBinding binding = tester.binding;
     // Use paused as the initial state.
@@ -20,6 +18,6 @@ void main() {
 
     // The lifecycleState should now be the state we passed above,
     // even though no lifecycle event was fired from the platform.
-    expect(ServicesBinding.instance.lifecycleState.toString(), equals('AppLifecycleState.paused'));
+    expect(ServicesBinding.instance!.lifecycleState.toString(), equals('AppLifecycleState.paused'));
   });
 }

packages/flutter/test/services/message_codecs_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
-
 // This files contains message codec tests that are supported both on the Web
 // and in the VM. For VM-only tests see message_codecs_vm_test.dart.
 
@@ -18,26 +16,25 @@ import 'message_codecs_testing.dart';
 
 void main() {
   group('Binary codec', () {
-    const MessageCodec<ByteData> binary = BinaryCodec();
+    const MessageCodec<ByteData?> binary = BinaryCodec();
     test('should encode and decode simple messages', () {
-      checkEncodeDecode<ByteData>(binary, null);
-      checkEncodeDecode<ByteData>(binary, ByteData(0));
-      checkEncodeDecode<ByteData>(binary, ByteData(4)..setInt32(0, -7));
+      checkEncodeDecode<ByteData?>(binary, null);
+      checkEncodeDecode<ByteData?>(binary, ByteData(0));
+      checkEncodeDecode<ByteData?>(binary, ByteData(4)..setInt32(0, -7));
     });
   });
   group('String codec', () {
-    const MessageCodec<String> string = StringCodec();
+    const MessageCodec<String?> string = StringCodec();
     test('should encode and decode simple messages', () {
-      checkEncodeDecode<String>(string, null);
-      checkEncodeDecode<String>(string, '');
-      checkEncodeDecode<String>(string, 'hello');
-      checkEncodeDecode<String>(string, 'special chars >\u263A\u{1F602}<');
+      checkEncodeDecode<String?>(string, null);
+      checkEncodeDecode<String?>(string, '');
+      checkEncodeDecode<String?>(string, 'hello');
+      checkEncodeDecode<String?>(string, 'special chars >\u263A\u{1F602}<');
     });
     test('ByteData with offset', () {
-      const MessageCodec<String> string = StringCodec();
-      final ByteData helloWorldByteData = string.encodeMessage('hello world');
-      final ByteData helloByteData = string.encodeMessage('hello');
-
+      const MessageCodec<String?> string = StringCodec();
+      final ByteData helloWorldByteData = string.encodeMessage('hello world')!;
+      final ByteData helloByteData = string.encodeMessage('hello')!;
       final ByteData offsetByteData = ByteData.view(
         helloWorldByteData.buffer,
         helloByteData.lengthInBytes,
@@ -97,7 +94,7 @@ void main() {
               e.details == 'errorDetails')));
     });
     test('should decode error envelope with native stacktrace.', () {
-      final ByteData errorData = stringCodec.encodeMessage(json
+      final ByteData? errorData = stringCodec.encodeMessage(json
           .encode(<dynamic>[
         'errorCode',
         'errorMessage',
@@ -105,7 +102,7 @@ void main() {
         'errorStacktrace'
       ]));
       expect(
-          () => jsonMethodCodec.decodeEnvelope(errorData),
+          () => jsonMethodCodec.decodeEnvelope(errorData!),
           throwsA(predicate((PlatformException e) =>
               e is PlatformException && e.stacktrace == 'errorStacktrace')));
     });

packages/flutter/test/services/message_codecs_testing.dart

@@ -23,9 +23,9 @@ void checkEncodeDecode<T>(MessageCodec<T> codec, T message) {
     expect(decoded, isNull);
   } else {
     expect(deepEquals(message, decoded), isTrue);
-    final ByteData encodedAgain = codec.encodeMessage(decoded)!;
+    final ByteData? encodedAgain = codec.encodeMessage(decoded);
     expect(
-      encodedAgain.buffer.asUint8List(),
+      encodedAgain!.buffer.asUint8List(),
       orderedEquals(encoded!.buffer.asUint8List()),
     );
   }

packages/flutter/test/services/message_codecs_vm_test.dart

@@ -2,7 +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
 
 // This file contains tests that are only supported by the Dart VM. For
 // example, on the Web there's no way to express large integers.

packages/flutter/test/services/platform_messages_test.dart

@@ -2,7 +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') // missing web infrastructure for plugins.
 
@@ -16,20 +15,20 @@ void main() {
     // Initialize all bindings because defaultBinaryMessenger.send() needs a window.
     TestWidgetsFlutterBinding.ensureInitialized();
 
-    final List<ByteData> log = <ByteData>[];
+    final List<ByteData?> log = <ByteData>[];
 
-    ServicesBinding.instance.defaultBinaryMessenger.setMockMessageHandler('test1', (ByteData message) async {
+    ServicesBinding.instance!.defaultBinaryMessenger.setMockMessageHandler('test1', (ByteData? message) async {
       log.add(message);
       return null;
     });
 
     final ByteData message = ByteData(2)..setUint16(0, 0xABCD);
-    await ServicesBinding.instance.defaultBinaryMessenger.send('test1', message);
+    await ServicesBinding.instance!.defaultBinaryMessenger.send('test1', message);
     expect(log, equals(<ByteData>[message]));
     log.clear();
 
-    ServicesBinding.instance.defaultBinaryMessenger.setMockMessageHandler('test1', null);
-    await ServicesBinding.instance.defaultBinaryMessenger.send('test1', message);
+    ServicesBinding.instance!.defaultBinaryMessenger.setMockMessageHandler('test1', null);
+    await ServicesBinding.instance!.defaultBinaryMessenger.send('test1', message);
     expect(log, isEmpty);
   });
 }

packages/flutter/test/services/platform_views_test.dart

@@ -2,7 +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/services.dart';
@@ -15,7 +14,7 @@ void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('Android', () {
-    FakeAndroidPlatformViewsController viewsController;
+    late FakeAndroidPlatformViewsController viewsController;
     setUp(() {
       viewsController = FakeAndroidPlatformViewsController();
     });
@@ -202,7 +201,7 @@ void main() {
   });
 
   group('iOS', () {
-    FakeIosPlatformViewsController viewsController;
+    late FakeIosPlatformViewsController viewsController;
     setUp(() {
       viewsController = FakeIosPlatformViewsController();
     });

packages/flutter/test/services/restoration_bucket_test.dart

@@ -2,7 +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/services.dart';
@@ -54,7 +53,7 @@ void main() {
     expect(manager.updateScheduled, isFalse);
 
     // Can store null.
-    bucket.write<bool>('value4', null);
+    bucket.write<bool?>('value4', null);
     expect(manager.updateScheduled, isTrue);
     expect(bucket.read<int>('value4'), null);
     manager.doSerialization();
@@ -111,7 +110,7 @@ void main() {
     expect(manager.updateScheduled, isFalse);
 
     // Can store null.
-    child.write<bool>('value4', null);
+    child.write<bool?>('value4', null);
     expect(manager.updateScheduled, isTrue);
     expect(child.read<int>('value4'), null);
     manager.doSerialization();
@@ -327,7 +326,7 @@ void main() {
     final RestorationBucket root = RestorationBucket.root(manager: manager, rawData: rawData);
 
     final RestorationBucket child = root.claimChild('child1', debugOwner: 'owner1');
-    final Object rawChildData = rawData[childrenMapKey]['child1'];
+    final Object rawChildData = rawData[childrenMapKey]['child1'] as Object;
     expect(rawChildData, isNotNull);
 
     expect(manager.updateScheduled, isFalse);
@@ -370,9 +369,9 @@ void main() {
     final RestorationBucket child2 = root.claimChild('child2', debugOwner: 'owner1');
     manager.doSerialization();
 
-    final Object rawChild1Data = rawData[childrenMapKey]['child1'];
+    final Object rawChild1Data = rawData[childrenMapKey]['child1'] as Object;
     expect(rawChild1Data, isNotNull);
-    final Object rawChild2Data = rawData[childrenMapKey]['child2'];
+    final Object rawChild2Data = rawData[childrenMapKey]['child2'] as Object;
     expect(rawChild2Data, isNotNull);
 
     expect(child1.restorationId, 'child1');
@@ -396,7 +395,7 @@ void main() {
     final Map<String, dynamic> rawData = _createRawDataSet();
     final RestorationBucket root = RestorationBucket.root(manager: manager, rawData: rawData);
 
-    final Object rawChild1Data = rawData[childrenMapKey]['child1'];
+    final Object rawChild1Data = rawData[childrenMapKey]['child1'] as Object;
     expect(rawChild1Data, isNotNull);
 
     final RestorationBucket child1 = root.claimChild('child1', debugOwner: 'owner1');
@@ -462,7 +461,7 @@ void main() {
     manager.doSerialization();
     expect(manager.updateScheduled, isFalse);
 
-    final Object childOfChildData = rawData[childrenMapKey]['child1'][childrenMapKey]['childOfChild'];
+    final Object childOfChildData = rawData[childrenMapKey]['child1'][childrenMapKey]['childOfChild'] as Object;
     expect(childOfChildData, isNotEmpty);
 
     root.adoptChild(childOfChild);
@@ -497,7 +496,7 @@ void main() {
     final RestorationBucket childOfChild = child.claimChild('child1', debugOwner: 'owner2');
     childOfChild.write<String>('foo', 'bar');
 
-    final Object childOfChildData = rawData[childrenMapKey]['child1'][childrenMapKey]['child1'];
+    final Object childOfChildData = rawData[childrenMapKey]['child1'][childrenMapKey]['child1'] as Object;
     expect(childOfChildData, isNotEmpty);
 
     expect(manager.updateScheduled, isTrue);

packages/flutter/test/services/system_chrome_test.dart

@@ -2,7 +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';
 
@@ -61,11 +60,10 @@ void main() {
   });
 
   test('setApplicationSwitcherDescription missing plugin', () async {
-    final List<ByteData> log = <ByteData>[];
+    final List<ByteData?> log = <ByteData>[];
 
-    ServicesBinding.instance.defaultBinaryMessenger.setMockMessageHandler('flutter/platform', (ByteData message) {
+    ServicesBinding.instance!.defaultBinaryMessenger.setMockMessageHandler('flutter/platform', (ByteData? message) async {
       log.add(message);
-      return null;
     });
 
     await SystemChrome.setApplicationSwitcherDescription(

packages/flutter/test/services/system_navigator_test.dart

@@ -2,7 +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/services.dart';
 import 'package:flutter_test/flutter_test.dart';

packages/flutter/test/services/system_sound_test.dart

@@ -2,7 +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/services.dart';
 import 'package:flutter_test/flutter_test.dart';

packages/flutter/test/services/text_formatter_test.dart

@@ -2,27 +2,25 @@
 // 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/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  TextEditingValue testOldValue;
-  TextEditingValue testNewValue;
+  TextEditingValue testOldValue = TextEditingValue.empty;
+  TextEditingValue testNewValue = TextEditingValue.empty;
 
   test('withFunction wraps formatting function', () {
     testOldValue = const TextEditingValue();
     testNewValue = const TextEditingValue();
 
-    TextEditingValue calledOldValue;
-    TextEditingValue calledNewValue;
+    late TextEditingValue calledOldValue;
+    late TextEditingValue calledNewValue;
 
     final TextInputFormatter formatterUnderTest = TextInputFormatter.withFunction(
       (TextEditingValue oldValue, TextEditingValue newValue) {
         calledOldValue = oldValue;
         calledNewValue = newValue;
-        return null;
+        return TextEditingValue.empty;
       }
     );