packages/flutter/test/widgets/restorable_property_test.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';

 void main() {
   testWidgets('value is not accessible when not registered', (WidgetTester tester) async {
     expect(() => RestorableNum<num>(0).value, throwsAssertionError);
     expect(() => RestorableDouble(1.0).value, throwsAssertionError);
     expect(() => RestorableInt(1).value, throwsAssertionError);
     expect(() => RestorableString('hello').value, throwsAssertionError);
     expect(() => RestorableBool(true).value, throwsAssertionError);
     expect(() => RestorableNumN<num?>(0).value, throwsAssertionError);
     expect(() => RestorableDoubleN(1.0).value, throwsAssertionError);
     expect(() => RestorableIntN(1).value, throwsAssertionError);
     expect(() => RestorableStringN('hello').value, throwsAssertionError);
     expect(() => RestorableBoolN(true).value, throwsAssertionError);
     expect(() => RestorableTextEditingController().value, throwsAssertionError);
     expect(() => RestorableDateTime(DateTime(2020, 4, 3)).value, throwsAssertionError);
     expect(() => RestorableDateTimeN(DateTime(2020, 4, 3)).value, throwsAssertionError);
     expect(() => _TestRestorableValue().value, throwsAssertionError);
   });

   testWidgets('work when not in restoration scope', (WidgetTester tester) async {
     await tester.pumpWidget(const _RestorableWidget());

     expect(find.text('hello world'), findsOneWidget);
     final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

     // Initialized to default values.
     expect(state.numValue.value, 99);
     expect(state.doubleValue.value, 123.2);
     expect(state.intValue.value, 42);
     expect(state.stringValue.value, 'hello world');
     expect(state.boolValue.value, false);
     expect(state.dateTimeValue.value, DateTime(2021, 3, 16));
     expect(state.nullableNumValue.value, null);
     expect(state.nullableDoubleValue.value, null);
     expect(state.nullableIntValue.value, null);
     expect(state.nullableStringValue.value, null);
     expect(state.nullableBoolValue.value, null);
     expect(state.nullableDateTimeValue.value, null);
     expect(state.controllerValue.value.text, 'FooBar');
     expect(state.objectValue.value, 55);

     // Modify values.
     state.setProperties(() {
       state.numValue.value = 42.2;
       state.doubleValue.value = 441.3;
       state.intValue.value = 10;
       state.stringValue.value = 'guten tag';
       state.boolValue.value = true;
       state.dateTimeValue.value = DateTime(2020, 7, 4);
       state.nullableNumValue.value = 5.0;
       state.nullableDoubleValue.value = 2.0;
       state.nullableIntValue.value = 1;
       state.nullableStringValue.value = 'hullo';
       state.nullableBoolValue.value = false;
       state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
       state.controllerValue.value.text = 'blabla';
       state.objectValue.value = 53;
     });
     await tester.pump();

     expect(state.numValue.value, 42.2);
     expect(state.doubleValue.value, 441.3);
     expect(state.intValue.value, 10);
     expect(state.stringValue.value, 'guten tag');
     expect(state.boolValue.value, true);
     expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
     expect(state.nullableNumValue.value, 5.0);
     expect(state.nullableDoubleValue.value, 2.0);
     expect(state.nullableIntValue.value, 1);
     expect(state.nullableStringValue.value, 'hullo');
     expect(state.nullableBoolValue.value, false);
     expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
     expect(state.controllerValue.value.text, 'blabla');
     expect(state.objectValue.value, 53);
     expect(find.text('guten tag'), findsOneWidget);
   });

   testWidgets('restart and restore', (WidgetTester tester) async {
     await tester.pumpWidget(const RootRestorationScope(
       restorationId: 'root-child',
       child: _RestorableWidget(),
     ));

     expect(find.text('hello world'), findsOneWidget);
     _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

     // Initialized to default values.
     expect(state.numValue.value, 99);
     expect(state.doubleValue.value, 123.2);
     expect(state.intValue.value, 42);
     expect(state.stringValue.value, 'hello world');
     expect(state.boolValue.value, false);
     expect(state.dateTimeValue.value, DateTime(2021, 3, 16));
     expect(state.nullableNumValue.value, null);
     expect(state.nullableDoubleValue.value, null);
     expect(state.nullableIntValue.value, null);
     expect(state.nullableStringValue.value, null);
     expect(state.nullableBoolValue.value, null);
     expect(state.nullableDateTimeValue.value, null);
     expect(state.controllerValue.value.text, 'FooBar');
     expect(state.objectValue.value, 55);

     // Modify values.
     state.setProperties(() {
       state.numValue.value = 42.2;
       state.doubleValue.value = 441.3;
       state.intValue.value = 10;
       state.stringValue.value = 'guten tag';
       state.boolValue.value = true;
       state.dateTimeValue.value = DateTime(2020, 7, 4);
       state.nullableNumValue.value = 5.0;
       state.nullableDoubleValue.value = 2.0;
       state.nullableIntValue.value = 1;
       state.nullableStringValue.value = 'hullo';
       state.nullableBoolValue.value = false;
       state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
       state.controllerValue.value.text = 'blabla';
       state.objectValue.value = 53;
     });
     await tester.pump();

     expect(state.numValue.value, 42.2);
     expect(state.doubleValue.value, 441.3);
     expect(state.intValue.value, 10);
     expect(state.stringValue.value, 'guten tag');
     expect(state.boolValue.value, true);
     expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
     expect(state.nullableNumValue.value, 5.0);
     expect(state.nullableDoubleValue.value, 2.0);
     expect(state.nullableIntValue.value, 1);
     expect(state.nullableStringValue.value, 'hullo');
     expect(state.nullableBoolValue.value, false);
     expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
     expect(state.controllerValue.value.text, 'blabla');
     expect(state.objectValue.value, 53);
     expect(find.text('guten tag'), findsOneWidget);

     // Restores to previous values.
     await tester.restartAndRestore();
     final _RestorableWidgetState oldState = state;
     state = tester.state(find.byType(_RestorableWidget));
     expect(state, isNot(same(oldState)));

     expect(state.numValue.value, 42.2);
     expect(state.doubleValue.value, 441.3);
     expect(state.intValue.value, 10);
     expect(state.stringValue.value, 'guten tag');
     expect(state.boolValue.value, true);
     expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
     expect(state.nullableNumValue.value, 5.0);
     expect(state.nullableDoubleValue.value, 2.0);
     expect(state.nullableIntValue.value, 1);
     expect(state.nullableStringValue.value, 'hullo');
     expect(state.nullableBoolValue.value, false);
     expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
     expect(state.controllerValue.value.text, 'blabla');
     expect(state.objectValue.value, 53);
     expect(find.text('guten tag'), findsOneWidget);
   });

   testWidgets('restore to older state', (WidgetTester tester) async {
     await tester.pumpWidget(const RootRestorationScope(
       restorationId: 'root-child',
       child: _RestorableWidget(),
     ));

     expect(find.text('hello world'), findsOneWidget);
     final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

     // Modify values.
     state.setProperties(() {
       state.numValue.value = 42.2;
       state.doubleValue.value = 441.3;
       state.intValue.value = 10;
       state.stringValue.value = 'guten tag';
       state.boolValue.value = true;
       state.dateTimeValue.value = DateTime(2020, 7, 4);
       state.nullableNumValue.value = 5.0;
       state.nullableDoubleValue.value = 2.0;
       state.nullableIntValue.value = 1;
       state.nullableStringValue.value = 'hullo';
       state.nullableBoolValue.value = false;
       state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
       state.controllerValue.value.text = 'blabla';
       state.objectValue.value = 53;
     });
     await tester.pump();
     expect(find.text('guten tag'), findsOneWidget);

     final TestRestorationData restorationData = await tester.getRestorationData();

     // Modify values.
     state.setProperties(() {
       state.numValue.value = 20;
       state.doubleValue.value = 20.0;
       state.intValue.value = 20;
       state.stringValue.value = 'ciao';
       state.boolValue.value = false;
       state.dateTimeValue.value = DateTime(2020, 3, 2);
       state.nullableNumValue.value = 20.0;
       state.nullableDoubleValue.value = 20.0;
       state.nullableIntValue.value = 20;
       state.nullableStringValue.value = 'ni hao';
       state.nullableBoolValue.value = null;
       state.nullableDateTimeValue.value = DateTime(2020, 5, 5);
       state.controllerValue.value.text = 'blub';
       state.objectValue.value = 20;
     });
     await tester.pump();
     expect(find.text('ciao'), findsOneWidget);
     final TextEditingController controller = state.controllerValue.value;

     // Restore to previous.
     await tester.restoreFrom(restorationData);
     expect(state.numValue.value, 42.2);
     expect(state.doubleValue.value, 441.3);
     expect(state.intValue.value, 10);
     expect(state.stringValue.value, 'guten tag');
     expect(state.boolValue.value, true);
     expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
     expect(state.nullableNumValue.value, 5.0);
     expect(state.nullableDoubleValue.value, 2.0);
     expect(state.nullableIntValue.value, 1);
     expect(state.nullableStringValue.value, 'hullo');
     expect(state.nullableBoolValue.value, false);
     expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
     expect(state.controllerValue.value.text, 'blabla');
     expect(state.objectValue.value, 53);
     expect(find.text('guten tag'), findsOneWidget);
     expect(state.controllerValue.value, isNot(same(controller)));

     // Restore to empty data will re-initialize to default values.
     await tester.restoreFrom(TestRestorationData.empty);
     expect(state.numValue.value, 99);
     expect(state.doubleValue.value, 123.2);
     expect(state.intValue.value, 42);
     expect(state.stringValue.value, 'hello world');
     expect(state.boolValue.value, false);
     expect(state.dateTimeValue.value, DateTime(2021, 3, 16));
     expect(state.nullableNumValue.value, null);
     expect(state.nullableDoubleValue.value, null);
     expect(state.nullableIntValue.value, null);
     expect(state.nullableStringValue.value, null);
     expect(state.nullableBoolValue.value, null);
     expect(state.nullableDateTimeValue.value, null);
     expect(state.controllerValue.value.text, 'FooBar');
     expect(state.objectValue.value, 55);
     expect(find.text('hello world'), findsOneWidget);
   });

   testWidgets('call notifiers when value changes', (WidgetTester tester) async {
     await tester.pumpWidget(const RootRestorationScope(
       restorationId: 'root-child',
       child: _RestorableWidget(),
     ));

     expect(find.text('hello world'), findsOneWidget);
     final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

     final List<String> notifyLog = <String>[];

     state.numValue.addListener(() {
       notifyLog.add('num');
     });
     state.doubleValue.addListener(() {
       notifyLog.add('double');
     });
     state.intValue.addListener(() {
       notifyLog.add('int');
     });
     state.stringValue.addListener(() {
       notifyLog.add('string');
     });
     state.boolValue.addListener(() {
       notifyLog.add('bool');
     });
     state.dateTimeValue.addListener(() {
       notifyLog.add('date-time');
     });
     state.nullableNumValue.addListener(() {
       notifyLog.add('nullable-num');
     });
     state.nullableDoubleValue.addListener(() {
       notifyLog.add('nullable-double');
     });
     state.nullableIntValue.addListener(() {
       notifyLog.add('nullable-int');
     });
     state.nullableStringValue.addListener(() {
       notifyLog.add('nullable-string');
     });
     state.nullableBoolValue.addListener(() {
       notifyLog.add('nullable-bool');
     });
     state.nullableDateTimeValue.addListener(() {
       notifyLog.add('nullable-date-time');
     });
     state.controllerValue.addListener(() {
       notifyLog.add('controller');
     });
     state.objectValue.addListener(() {
       notifyLog.add('object');
     });

     state.setProperties(() {
       state.numValue.value = 42.2;
     });
     expect(notifyLog.single, 'num');
     notifyLog.clear();

     state.setProperties(() {
       state.doubleValue.value = 42.2;
     });
     expect(notifyLog.single, 'double');
     notifyLog.clear();

     state.setProperties(() {
       state.intValue.value = 45;
     });
     expect(notifyLog.single, 'int');
     notifyLog.clear();

     state.setProperties(() {
       state.stringValue.value = 'bar';
     });
     expect(notifyLog.single, 'string');
     notifyLog.clear();

     state.setProperties(() {
       state.boolValue.value = true;
     });
     expect(notifyLog.single, 'bool');
     notifyLog.clear();

     state.setProperties(() {
       state.dateTimeValue.value = DateTime(2020, 7, 4);
     });
     expect(notifyLog.single, 'date-time');
     notifyLog.clear();

     state.setProperties(() {
       state.nullableNumValue.value = 42.2;
     });
     expect(notifyLog.single, 'nullable-num');
     notifyLog.clear();

     state.setProperties(() {
       state.nullableDoubleValue.value = 42.2;
     });
     expect(notifyLog.single, 'nullable-double');
     notifyLog.clear();

     state.setProperties(() {
       state.nullableIntValue.value = 45;
     });
     expect(notifyLog.single, 'nullable-int');
     notifyLog.clear();

     state.setProperties(() {
       state.nullableStringValue.value = 'bar';
     });
     expect(notifyLog.single, 'nullable-string');
     notifyLog.clear();

     state.setProperties(() {
       state.nullableBoolValue.value = true;
     });
     expect(notifyLog.single, 'nullable-bool');
     notifyLog.clear();

     state.setProperties(() {
       state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
     });
     expect(notifyLog.single, 'nullable-date-time');
     notifyLog.clear();

     state.setProperties(() {
       state.controllerValue.value.text = 'foo';
     });
     expect(notifyLog.single, 'controller');
     notifyLog.clear();

     state.setProperties(() {
       state.objectValue.value = 42;
     });
     expect(notifyLog.single, 'object');
     notifyLog.clear();

     await tester.pump();
     expect(find.text('bar'), findsOneWidget);

     // Does not notify when set to same value.
     state.setProperties(() {
       state.numValue.value = 42.2;
       state.doubleValue.value = 42.2;
       state.intValue.value = 45;
       state.stringValue.value = 'bar';
       state.boolValue.value = true;
       state.dateTimeValue.value = DateTime(2020, 7, 4);
       state.nullableNumValue.value = 42.2;
       state.nullableDoubleValue.value = 42.2;
       state.nullableIntValue.value = 45;
       state.nullableStringValue.value = 'bar';
       state.nullableBoolValue.value = true;
       state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
       state.controllerValue.value.text = 'foo';
       state.objectValue.value = 42;
     });

     expect(notifyLog, isEmpty);
   });

   testWidgets('RestorableValue calls didUpdateValue', (WidgetTester tester) async {
     await tester.pumpWidget(const RootRestorationScope(
       restorationId: 'root-child',
       child: _RestorableWidget(),
     ));

     expect(find.text('hello world'), findsOneWidget);
     final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

     expect(state.objectValue.didUpdateValueCallCount, 0);

     state.setProperties(() {
       state.objectValue.value = 44;
     });
     expect(state.objectValue.didUpdateValueCallCount, 1);

     await tester.pump();

     state.setProperties(() {
       state.objectValue.value = 44;
     });
     expect(state.objectValue.didUpdateValueCallCount, 1);
   });


   testWidgets('RestorableN types are properly defined', (WidgetTester tester) async {
     await tester.pumpWidget(const RootRestorationScope(
       restorationId: 'root-child',
       child: _RestorableWidget(),
     ));

     expect(find.text('hello world'), findsOneWidget);
     final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));
     state.setProperties(() {
       state.nullableIntValue.value = 24;
       state.nullableDoubleValue.value = 1.5;
     });

     // The following types of asserts do not work. They pass even when the
     // type of `value` is a `num` and not an `int` because `num` is a
     // superclass of `int`. This test is intended to prevent a regression
     // where RestorableIntN's value is of type `num?`, but it is passed into
     // a function which requires an `int?` value. This resulted in Dart
     // compile-time errors.
     //
     // expect(state.nullableIntValue.value, isA<int>());
     // expect(state.nullableIntValue.value.runtimeType, int);

     // A function that takes a nullable int value.
     void takesInt(int? value) {}
     // The following would result in a Dart compile-time error if `value` is
     // a `num?` instead of an `int?`.
     takesInt(state.nullableIntValue.value);

     // A function that takes a nullable double value.
     void takesDouble(double? value) {}
     // The following would result in a Dart compile-time error if `value` is
     // a `num?` instead of a `double?`.
     takesDouble(state.nullableDoubleValue.value);
   });
 }

 class _TestRestorableValue extends RestorableValue<Object?> {
   @override
   Object createDefaultValue() {
     return 55;
   }

   int didUpdateValueCallCount = 0;

   @override
   void didUpdateValue(Object? oldValue) {
     didUpdateValueCallCount++;
     notifyListeners();
   }

   @override
   Object? fromPrimitives(Object? data) {
     return data;
   }

   @override
   Object? toPrimitives() {
     return value;
   }
 }

 class _RestorableWidget extends StatefulWidget {
   const _RestorableWidget();

   @override
   State<_RestorableWidget> createState() => _RestorableWidgetState();
 }

 class _RestorableWidgetState extends State<_RestorableWidget> with RestorationMixin {
   final RestorableNum<num> numValue = RestorableNum<num>(99);
   final RestorableDouble doubleValue = RestorableDouble(123.2);
   final RestorableInt intValue = RestorableInt(42);
   final RestorableString stringValue = RestorableString('hello world');
   final RestorableBool boolValue = RestorableBool(false);
   final RestorableDateTime dateTimeValue = RestorableDateTime(DateTime(2021, 3, 16));
   final RestorableNumN<num?> nullableNumValue = RestorableNumN<num?>(null);
   final RestorableDoubleN nullableDoubleValue = RestorableDoubleN(null);
   final RestorableIntN nullableIntValue = RestorableIntN(null);
   final RestorableStringN nullableStringValue = RestorableStringN(null);
   final RestorableBoolN nullableBoolValue = RestorableBoolN(null);
   final RestorableDateTimeN nullableDateTimeValue = RestorableDateTimeN(null);
   final RestorableTextEditingController controllerValue = RestorableTextEditingController(text: 'FooBar');
   final _TestRestorableValue objectValue = _TestRestorableValue();

   @override
   void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
     registerForRestoration(numValue, 'num');
     registerForRestoration(doubleValue, 'double');
     registerForRestoration(intValue, 'int');
     registerForRestoration(stringValue, 'string');
     registerForRestoration(boolValue, 'bool');
     registerForRestoration(dateTimeValue, 'dateTime');
     registerForRestoration(nullableNumValue, 'nullableNum');
     registerForRestoration(nullableDoubleValue, 'nullableDouble');
     registerForRestoration(nullableIntValue, 'nullableInt');
     registerForRestoration(nullableStringValue, 'nullableString');
     registerForRestoration(nullableBoolValue, 'nullableBool');
     registerForRestoration(nullableDateTimeValue, 'nullableDateTime');
     registerForRestoration(controllerValue, 'controller');
     registerForRestoration(objectValue, 'object');
   }

   void setProperties(VoidCallback callback) {
     setState(callback);
   }

   @override
   Widget build(BuildContext context) {
     return Text(stringValue.value, textDirection: TextDirection.ltr);
   }

   @override
   String get restorationId => 'widget';
 }
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'package:flutter/widgets.dart';
	import 'package:flutter_test/flutter_test.dart';

	void main() {
	testWidgets('value is not accessible when not registered', (WidgetTester tester) async {
	expect(() => RestorableNum<num>(0).value, throwsAssertionError);
	expect(() => RestorableDouble(1.0).value, throwsAssertionError);
	expect(() => RestorableInt(1).value, throwsAssertionError);
	expect(() => RestorableString('hello').value, throwsAssertionError);
	expect(() => RestorableBool(true).value, throwsAssertionError);
	expect(() => RestorableNumN<num?>(0).value, throwsAssertionError);
	expect(() => RestorableDoubleN(1.0).value, throwsAssertionError);
	expect(() => RestorableIntN(1).value, throwsAssertionError);
	expect(() => RestorableStringN('hello').value, throwsAssertionError);
	expect(() => RestorableBoolN(true).value, throwsAssertionError);
	expect(() => RestorableTextEditingController().value, throwsAssertionError);
	expect(() => RestorableDateTime(DateTime(2020, 4, 3)).value, throwsAssertionError);
	expect(() => RestorableDateTimeN(DateTime(2020, 4, 3)).value, throwsAssertionError);
	expect(() => _TestRestorableValue().value, throwsAssertionError);
	});

	testWidgets('work when not in restoration scope', (WidgetTester tester) async {
	await tester.pumpWidget(const _RestorableWidget());

	expect(find.text('hello world'), findsOneWidget);
	final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

	// Initialized to default values.
	expect(state.numValue.value, 99);
	expect(state.doubleValue.value, 123.2);
	expect(state.intValue.value, 42);
	expect(state.stringValue.value, 'hello world');
	expect(state.boolValue.value, false);
	expect(state.dateTimeValue.value, DateTime(2021, 3, 16));
	expect(state.nullableNumValue.value, null);
	expect(state.nullableDoubleValue.value, null);
	expect(state.nullableIntValue.value, null);
	expect(state.nullableStringValue.value, null);
	expect(state.nullableBoolValue.value, null);
	expect(state.nullableDateTimeValue.value, null);
	expect(state.controllerValue.value.text, 'FooBar');
	expect(state.objectValue.value, 55);

	// Modify values.
	state.setProperties(() {
	state.numValue.value = 42.2;
	state.doubleValue.value = 441.3;
	state.intValue.value = 10;
	state.stringValue.value = 'guten tag';
	state.boolValue.value = true;
	state.dateTimeValue.value = DateTime(2020, 7, 4);
	state.nullableNumValue.value = 5.0;
	state.nullableDoubleValue.value = 2.0;
	state.nullableIntValue.value = 1;
	state.nullableStringValue.value = 'hullo';
	state.nullableBoolValue.value = false;
	state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
	state.controllerValue.value.text = 'blabla';
	state.objectValue.value = 53;
	});
	await tester.pump();

	expect(state.numValue.value, 42.2);
	expect(state.doubleValue.value, 441.3);
	expect(state.intValue.value, 10);
	expect(state.stringValue.value, 'guten tag');
	expect(state.boolValue.value, true);
	expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
	expect(state.nullableNumValue.value, 5.0);
	expect(state.nullableDoubleValue.value, 2.0);
	expect(state.nullableIntValue.value, 1);
	expect(state.nullableStringValue.value, 'hullo');
	expect(state.nullableBoolValue.value, false);
	expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
	expect(state.controllerValue.value.text, 'blabla');
	expect(state.objectValue.value, 53);
	expect(find.text('guten tag'), findsOneWidget);
	});

	testWidgets('restart and restore', (WidgetTester tester) async {
	await tester.pumpWidget(const RootRestorationScope(
	restorationId: 'root-child',
	child: _RestorableWidget(),
	));

	expect(find.text('hello world'), findsOneWidget);
	_RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

	// Initialized to default values.
	expect(state.numValue.value, 99);
	expect(state.doubleValue.value, 123.2);
	expect(state.intValue.value, 42);
	expect(state.stringValue.value, 'hello world');
	expect(state.boolValue.value, false);
	expect(state.dateTimeValue.value, DateTime(2021, 3, 16));
	expect(state.nullableNumValue.value, null);
	expect(state.nullableDoubleValue.value, null);
	expect(state.nullableIntValue.value, null);
	expect(state.nullableStringValue.value, null);
	expect(state.nullableBoolValue.value, null);
	expect(state.nullableDateTimeValue.value, null);
	expect(state.controllerValue.value.text, 'FooBar');
	expect(state.objectValue.value, 55);

	// Modify values.
	state.setProperties(() {
	state.numValue.value = 42.2;
	state.doubleValue.value = 441.3;
	state.intValue.value = 10;
	state.stringValue.value = 'guten tag';
	state.boolValue.value = true;
	state.dateTimeValue.value = DateTime(2020, 7, 4);
	state.nullableNumValue.value = 5.0;
	state.nullableDoubleValue.value = 2.0;
	state.nullableIntValue.value = 1;
	state.nullableStringValue.value = 'hullo';
	state.nullableBoolValue.value = false;
	state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
	state.controllerValue.value.text = 'blabla';
	state.objectValue.value = 53;
	});
	await tester.pump();

	expect(state.numValue.value, 42.2);
	expect(state.doubleValue.value, 441.3);
	expect(state.intValue.value, 10);
	expect(state.stringValue.value, 'guten tag');
	expect(state.boolValue.value, true);
	expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
	expect(state.nullableNumValue.value, 5.0);
	expect(state.nullableDoubleValue.value, 2.0);
	expect(state.nullableIntValue.value, 1);
	expect(state.nullableStringValue.value, 'hullo');
	expect(state.nullableBoolValue.value, false);
	expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
	expect(state.controllerValue.value.text, 'blabla');
	expect(state.objectValue.value, 53);
	expect(find.text('guten tag'), findsOneWidget);

	// Restores to previous values.
	await tester.restartAndRestore();
	final _RestorableWidgetState oldState = state;
	state = tester.state(find.byType(_RestorableWidget));
	expect(state, isNot(same(oldState)));

	expect(state.numValue.value, 42.2);
	expect(state.doubleValue.value, 441.3);
	expect(state.intValue.value, 10);
	expect(state.stringValue.value, 'guten tag');
	expect(state.boolValue.value, true);
	expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
	expect(state.nullableNumValue.value, 5.0);
	expect(state.nullableDoubleValue.value, 2.0);
	expect(state.nullableIntValue.value, 1);
	expect(state.nullableStringValue.value, 'hullo');
	expect(state.nullableBoolValue.value, false);
	expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
	expect(state.controllerValue.value.text, 'blabla');
	expect(state.objectValue.value, 53);
	expect(find.text('guten tag'), findsOneWidget);
	});

	testWidgets('restore to older state', (WidgetTester tester) async {
	await tester.pumpWidget(const RootRestorationScope(
	restorationId: 'root-child',
	child: _RestorableWidget(),
	));

	expect(find.text('hello world'), findsOneWidget);
	final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

	// Modify values.
	state.setProperties(() {
	state.numValue.value = 42.2;
	state.doubleValue.value = 441.3;
	state.intValue.value = 10;
	state.stringValue.value = 'guten tag';
	state.boolValue.value = true;
	state.dateTimeValue.value = DateTime(2020, 7, 4);
	state.nullableNumValue.value = 5.0;
	state.nullableDoubleValue.value = 2.0;
	state.nullableIntValue.value = 1;
	state.nullableStringValue.value = 'hullo';
	state.nullableBoolValue.value = false;
	state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
	state.controllerValue.value.text = 'blabla';
	state.objectValue.value = 53;
	});
	await tester.pump();
	expect(find.text('guten tag'), findsOneWidget);

	final TestRestorationData restorationData = await tester.getRestorationData();

	// Modify values.
	state.setProperties(() {
	state.numValue.value = 20;
	state.doubleValue.value = 20.0;
	state.intValue.value = 20;
	state.stringValue.value = 'ciao';
	state.boolValue.value = false;
	state.dateTimeValue.value = DateTime(2020, 3, 2);
	state.nullableNumValue.value = 20.0;
	state.nullableDoubleValue.value = 20.0;
	state.nullableIntValue.value = 20;
	state.nullableStringValue.value = 'ni hao';
	state.nullableBoolValue.value = null;
	state.nullableDateTimeValue.value = DateTime(2020, 5, 5);
	state.controllerValue.value.text = 'blub';
	state.objectValue.value = 20;
	});
	await tester.pump();
	expect(find.text('ciao'), findsOneWidget);
	final TextEditingController controller = state.controllerValue.value;

	// Restore to previous.
	await tester.restoreFrom(restorationData);
	expect(state.numValue.value, 42.2);
	expect(state.doubleValue.value, 441.3);
	expect(state.intValue.value, 10);
	expect(state.stringValue.value, 'guten tag');
	expect(state.boolValue.value, true);
	expect(state.dateTimeValue.value, DateTime(2020, 7, 4));
	expect(state.nullableNumValue.value, 5.0);
	expect(state.nullableDoubleValue.value, 2.0);
	expect(state.nullableIntValue.value, 1);
	expect(state.nullableStringValue.value, 'hullo');
	expect(state.nullableBoolValue.value, false);
	expect(state.nullableDateTimeValue.value, DateTime(2020, 4, 4));
	expect(state.controllerValue.value.text, 'blabla');
	expect(state.objectValue.value, 53);
	expect(find.text('guten tag'), findsOneWidget);
	expect(state.controllerValue.value, isNot(same(controller)));

	// Restore to empty data will re-initialize to default values.
	await tester.restoreFrom(TestRestorationData.empty);
	expect(state.numValue.value, 99);
	expect(state.doubleValue.value, 123.2);
	expect(state.intValue.value, 42);
	expect(state.stringValue.value, 'hello world');
	expect(state.boolValue.value, false);
	expect(state.dateTimeValue.value, DateTime(2021, 3, 16));
	expect(state.nullableNumValue.value, null);
	expect(state.nullableDoubleValue.value, null);
	expect(state.nullableIntValue.value, null);
	expect(state.nullableStringValue.value, null);
	expect(state.nullableBoolValue.value, null);
	expect(state.nullableDateTimeValue.value, null);
	expect(state.controllerValue.value.text, 'FooBar');
	expect(state.objectValue.value, 55);
	expect(find.text('hello world'), findsOneWidget);
	});

	testWidgets('call notifiers when value changes', (WidgetTester tester) async {
	await tester.pumpWidget(const RootRestorationScope(
	restorationId: 'root-child',
	child: _RestorableWidget(),
	));

	expect(find.text('hello world'), findsOneWidget);
	final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

	final List<String> notifyLog = <String>[];

	state.numValue.addListener(() {
	notifyLog.add('num');
	});
	state.doubleValue.addListener(() {
	notifyLog.add('double');
	});
	state.intValue.addListener(() {
	notifyLog.add('int');
	});
	state.stringValue.addListener(() {
	notifyLog.add('string');
	});
	state.boolValue.addListener(() {
	notifyLog.add('bool');
	});
	state.dateTimeValue.addListener(() {
	notifyLog.add('date-time');
	});
	state.nullableNumValue.addListener(() {
	notifyLog.add('nullable-num');
	});
	state.nullableDoubleValue.addListener(() {
	notifyLog.add('nullable-double');
	});
	state.nullableIntValue.addListener(() {
	notifyLog.add('nullable-int');
	});
	state.nullableStringValue.addListener(() {
	notifyLog.add('nullable-string');
	});
	state.nullableBoolValue.addListener(() {
	notifyLog.add('nullable-bool');
	});
	state.nullableDateTimeValue.addListener(() {
	notifyLog.add('nullable-date-time');
	});
	state.controllerValue.addListener(() {
	notifyLog.add('controller');
	});
	state.objectValue.addListener(() {
	notifyLog.add('object');
	});

	state.setProperties(() {
	state.numValue.value = 42.2;
	});
	expect(notifyLog.single, 'num');
	notifyLog.clear();

	state.setProperties(() {
	state.doubleValue.value = 42.2;
	});
	expect(notifyLog.single, 'double');
	notifyLog.clear();

	state.setProperties(() {
	state.intValue.value = 45;
	});
	expect(notifyLog.single, 'int');
	notifyLog.clear();

	state.setProperties(() {
	state.stringValue.value = 'bar';
	});
	expect(notifyLog.single, 'string');
	notifyLog.clear();

	state.setProperties(() {
	state.boolValue.value = true;
	});
	expect(notifyLog.single, 'bool');
	notifyLog.clear();

	state.setProperties(() {
	state.dateTimeValue.value = DateTime(2020, 7, 4);
	});
	expect(notifyLog.single, 'date-time');
	notifyLog.clear();

	state.setProperties(() {
	state.nullableNumValue.value = 42.2;
	});
	expect(notifyLog.single, 'nullable-num');
	notifyLog.clear();

	state.setProperties(() {
	state.nullableDoubleValue.value = 42.2;
	});
	expect(notifyLog.single, 'nullable-double');
	notifyLog.clear();

	state.setProperties(() {
	state.nullableIntValue.value = 45;
	});
	expect(notifyLog.single, 'nullable-int');
	notifyLog.clear();

	state.setProperties(() {
	state.nullableStringValue.value = 'bar';
	});
	expect(notifyLog.single, 'nullable-string');
	notifyLog.clear();

	state.setProperties(() {
	state.nullableBoolValue.value = true;
	});
	expect(notifyLog.single, 'nullable-bool');
	notifyLog.clear();

	state.setProperties(() {
	state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
	});
	expect(notifyLog.single, 'nullable-date-time');
	notifyLog.clear();

	state.setProperties(() {
	state.controllerValue.value.text = 'foo';
	});
	expect(notifyLog.single, 'controller');
	notifyLog.clear();

	state.setProperties(() {
	state.objectValue.value = 42;
	});
	expect(notifyLog.single, 'object');
	notifyLog.clear();

	await tester.pump();
	expect(find.text('bar'), findsOneWidget);

	// Does not notify when set to same value.
	state.setProperties(() {
	state.numValue.value = 42.2;
	state.doubleValue.value = 42.2;
	state.intValue.value = 45;
	state.stringValue.value = 'bar';
	state.boolValue.value = true;
	state.dateTimeValue.value = DateTime(2020, 7, 4);
	state.nullableNumValue.value = 42.2;
	state.nullableDoubleValue.value = 42.2;
	state.nullableIntValue.value = 45;
	state.nullableStringValue.value = 'bar';
	state.nullableBoolValue.value = true;
	state.nullableDateTimeValue.value = DateTime(2020, 4, 4);
	state.controllerValue.value.text = 'foo';
	state.objectValue.value = 42;
	});

	expect(notifyLog, isEmpty);
	});

	testWidgets('RestorableValue calls didUpdateValue', (WidgetTester tester) async {
	await tester.pumpWidget(const RootRestorationScope(
	restorationId: 'root-child',
	child: _RestorableWidget(),
	));

	expect(find.text('hello world'), findsOneWidget);
	final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));

	expect(state.objectValue.didUpdateValueCallCount, 0);

	state.setProperties(() {
	state.objectValue.value = 44;
	});
	expect(state.objectValue.didUpdateValueCallCount, 1);

	await tester.pump();

	state.setProperties(() {
	state.objectValue.value = 44;
	});
	expect(state.objectValue.didUpdateValueCallCount, 1);
	});


	testWidgets('RestorableN types are properly defined', (WidgetTester tester) async {
	await tester.pumpWidget(const RootRestorationScope(
	restorationId: 'root-child',
	child: _RestorableWidget(),
	));

	expect(find.text('hello world'), findsOneWidget);
	final _RestorableWidgetState state = tester.state(find.byType(_RestorableWidget));
	state.setProperties(() {
	state.nullableIntValue.value = 24;
	state.nullableDoubleValue.value = 1.5;
	});

	// The following types of asserts do not work. They pass even when the
	// type of `value` is a `num` and not an `int` because `num` is a
	// superclass of `int`. This test is intended to prevent a regression
	// where RestorableIntN's value is of type `num?`, but it is passed into
	// a function which requires an `int?` value. This resulted in Dart
	// compile-time errors.
	//
	// expect(state.nullableIntValue.value, isA<int>());
	// expect(state.nullableIntValue.value.runtimeType, int);

	// A function that takes a nullable int value.
	void takesInt(int? value) {}
	// The following would result in a Dart compile-time error if `value` is
	// a `num?` instead of an `int?`.
	takesInt(state.nullableIntValue.value);

	// A function that takes a nullable double value.
	void takesDouble(double? value) {}
	// The following would result in a Dart compile-time error if `value` is
	// a `num?` instead of a `double?`.
	takesDouble(state.nullableDoubleValue.value);
	});
	}

	class _TestRestorableValue extends RestorableValue<Object?> {
	@override
	Object createDefaultValue() {
	return 55;
	}

	int didUpdateValueCallCount = 0;

	@override
	void didUpdateValue(Object? oldValue) {
	didUpdateValueCallCount++;
	notifyListeners();
	}

	@override
	Object? fromPrimitives(Object? data) {
	return data;
	}

	@override
	Object? toPrimitives() {
	return value;
	}
	}

	class _RestorableWidget extends StatefulWidget {
	const _RestorableWidget();

	@override
	State<_RestorableWidget> createState() => _RestorableWidgetState();
	}

	class _RestorableWidgetState extends State<_RestorableWidget> with RestorationMixin {
	final RestorableNum<num> numValue = RestorableNum<num>(99);
	final RestorableDouble doubleValue = RestorableDouble(123.2);
	final RestorableInt intValue = RestorableInt(42);
	final RestorableString stringValue = RestorableString('hello world');
	final RestorableBool boolValue = RestorableBool(false);
	final RestorableDateTime dateTimeValue = RestorableDateTime(DateTime(2021, 3, 16));
	final RestorableNumN<num?> nullableNumValue = RestorableNumN<num?>(null);
	final RestorableDoubleN nullableDoubleValue = RestorableDoubleN(null);
	final RestorableIntN nullableIntValue = RestorableIntN(null);
	final RestorableStringN nullableStringValue = RestorableStringN(null);
	final RestorableBoolN nullableBoolValue = RestorableBoolN(null);
	final RestorableDateTimeN nullableDateTimeValue = RestorableDateTimeN(null);
	final RestorableTextEditingController controllerValue = RestorableTextEditingController(text: 'FooBar');
	final _TestRestorableValue objectValue = _TestRestorableValue();

	@override
	void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
	registerForRestoration(numValue, 'num');
	registerForRestoration(doubleValue, 'double');
	registerForRestoration(intValue, 'int');
	registerForRestoration(stringValue, 'string');
	registerForRestoration(boolValue, 'bool');
	registerForRestoration(dateTimeValue, 'dateTime');
	registerForRestoration(nullableNumValue, 'nullableNum');
	registerForRestoration(nullableDoubleValue, 'nullableDouble');
	registerForRestoration(nullableIntValue, 'nullableInt');
	registerForRestoration(nullableStringValue, 'nullableString');
	registerForRestoration(nullableBoolValue, 'nullableBool');
	registerForRestoration(nullableDateTimeValue, 'nullableDateTime');
	registerForRestoration(controllerValue, 'controller');
	registerForRestoration(objectValue, 'object');
	}

	void setProperties(VoidCallback callback) {
	setState(callback);
	}

	@override
	Widget build(BuildContext context) {
	return Text(stringValue.value, textDirection: TextDirection.ltr);
	}

	@override
	String get restorationId => 'widget';
	}