packages/flutter/test/widgets/inherited_test.dart

// 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/material.dart';
import 'package:flutter_test/flutter_test.dart';

import 'test_widgets.dart';

class TestInherited extends InheritedWidget {
  const TestInherited({ Key? key, required Widget child, this.shouldNotify = true })
    : super(key: key, child: child);

  final bool shouldNotify;

  @override
  bool updateShouldNotify(InheritedWidget oldWidget) {
    return shouldNotify;
  }
}

class ValueInherited extends InheritedWidget {
  const ValueInherited({ Key? key, required Widget child, required this.value })
    : super(key: key, child: child);

  final int value;

  @override
  bool updateShouldNotify(ValueInherited oldWidget) => value != oldWidget.value;
}

class ExpectFail extends StatefulWidget {
  const ExpectFail(this.onError, { Key? key }) : super(key: key);
  final VoidCallback onError;

  @override
  ExpectFailState createState() => ExpectFailState();
}

class ExpectFailState extends State<ExpectFail> {
  @override
  void initState() {
    super.initState();
    try {
      context.dependOnInheritedWidgetOfExactType<TestInherited>(); // should fail
    } catch (e) {
      widget.onError();
    }
  }

  @override
  Widget build(BuildContext context) => Container();
}

class ChangeNotifierInherited extends InheritedNotifier<ChangeNotifier> {
  const ChangeNotifierInherited({ Key? key, required Widget child, ChangeNotifier? notifier })
    : super(key: key, child: child, notifier: notifier);
}

void main() {
  testWidgets('Inherited notifies dependents', (WidgetTester tester) async {
    final List<TestInherited> log = <TestInherited>[];

    final Builder builder = Builder(
      builder: (BuildContext context) {
        log.add(context.dependOnInheritedWidgetOfExactType<TestInherited>()!);
        return Container();
      },
    );

    final TestInherited first = TestInherited(child: builder);
    await tester.pumpWidget(first);

    expect(log, equals(<TestInherited>[first]));

    final TestInherited second = TestInherited(shouldNotify: false, child: builder);
    await tester.pumpWidget(second);

    expect(log, equals(<TestInherited>[first]));

    final TestInherited third = TestInherited(child: builder);
    await tester.pumpWidget(third);

    expect(log, equals(<TestInherited>[first, third]));
  });

  testWidgets('Update inherited when reparenting state', (WidgetTester tester) async {
    final GlobalKey globalKey = GlobalKey();
    final List<TestInherited> log = <TestInherited>[];

    TestInherited build() {
      return TestInherited(
        key: UniqueKey(),
        child: Container(
          key: globalKey,
          child: Builder(
            builder: (BuildContext context) {
              log.add(context.dependOnInheritedWidgetOfExactType<TestInherited>()!);
              return Container();
            },
          ),
        ),
      );
    }

    final TestInherited first = build();
    await tester.pumpWidget(first);

    expect(log, equals(<TestInherited>[first]));

    final TestInherited second = build();
    await tester.pumpWidget(second);

    expect(log, equals(<TestInherited>[first, second]));
  });

  testWidgets('Update inherited when removing node', (WidgetTester tester) async {
    final List<String> log = <String>[];

    await tester.pumpWidget(
      ValueInherited(
        value: 1,
        child: FlipWidget(
          left: ValueInherited(
            value: 2,
            child: ValueInherited(
              value: 3,
              child: Builder(
                builder: (BuildContext context) {
                  final ValueInherited v = context.dependOnInheritedWidgetOfExactType<ValueInherited>()!;
                  log.add('a: ${v.value}');
                  return const Text('', textDirection: TextDirection.ltr);
                },
              ),
            ),
          ),
          right: ValueInherited(
            value: 2,
            child: Builder(
              builder: (BuildContext context) {
                final ValueInherited v = context.dependOnInheritedWidgetOfExactType<ValueInherited>()!;
                log.add('b: ${v.value}');
                return const Text('', textDirection: TextDirection.ltr);
              },
            ),
          ),
        ),
      ),
    );

    expect(log, equals(<String>['a: 3']));
    log.clear();

    await tester.pump();

    expect(log, equals(<String>[]));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<String>['b: 2']));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<String>['a: 3']));
    log.clear();
  });

  testWidgets('Update inherited when removing node and child has global key', (WidgetTester tester) async {

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

    final Key key = GlobalKey();

    await tester.pumpWidget(
      ValueInherited(
        value: 1,
        child: FlipWidget(
          left: ValueInherited(
            value: 2,
            child: ValueInherited(
              value: 3,
              child: Container(
                key: key,
                child: Builder(
                  builder: (BuildContext context) {
                    final ValueInherited v = context.dependOnInheritedWidgetOfExactType<ValueInherited>()!;
                    log.add('a: ${v.value}');
                    return const Text('', textDirection: TextDirection.ltr);
                  },
                ),
              ),
            ),
          ),
          right: ValueInherited(
            value: 2,
            child: Container(
              key: key,
              child: Builder(
                builder: (BuildContext context) {
                  final ValueInherited v = context.dependOnInheritedWidgetOfExactType<ValueInherited>()!;
                  log.add('b: ${v.value}');
                  return const Text('', textDirection: TextDirection.ltr);
                },
              ),
            ),
          ),
        ),
      ),
    );

    expect(log, equals(<String>['a: 3']));
    log.clear();

    await tester.pump();

    expect(log, equals(<String>[]));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<String>['b: 2']));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<String>['a: 3']));
    log.clear();
  });

  testWidgets('Update inherited when removing node and child has global key with constant child', (WidgetTester tester) async {
    final List<int> log = <int>[];

    final Key key = GlobalKey();

    final Widget child = Builder(
      builder: (BuildContext context) {
        final ValueInherited v = context.dependOnInheritedWidgetOfExactType<ValueInherited>()!;
        log.add(v.value);
        return const Text('', textDirection: TextDirection.ltr);
      },
    );

    await tester.pumpWidget(
      ValueInherited(
        value: 1,
        child: FlipWidget(
          left: ValueInherited(
            value: 2,
            child: ValueInherited(
              value: 3,
              child: Container(
                key: key,
                child: child,
              ),
            ),
          ),
          right: ValueInherited(
            value: 2,
            child: Container(
              key: key,
              child: child,
            ),
          ),
        ),
      ),
    );

    expect(log, equals(<int>[3]));
    log.clear();

    await tester.pump();

    expect(log, equals(<int>[]));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<int>[2]));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<int>[3]));
    log.clear();
  });

  testWidgets('Update inherited when removing node and child has global key with constant child, minimised', (WidgetTester tester) async {

    final List<int> log = <int>[];

    final Widget child = Builder(
      key: GlobalKey(),
      builder: (BuildContext context) {
        final ValueInherited v = context.dependOnInheritedWidgetOfExactType<ValueInherited>()!;
        log.add(v.value);
        return const Text('', textDirection: TextDirection.ltr);
      },
    );

    await tester.pumpWidget(
      ValueInherited(
        value: 2,
        child: FlipWidget(
          left: ValueInherited(
            value: 3,
            child: child,
          ),
          right: child,
        ),
      ),
    );

    expect(log, equals(<int>[3]));
    log.clear();

    await tester.pump();

    expect(log, equals(<int>[]));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<int>[2]));
    log.clear();

    flipStatefulWidget(tester);
    await tester.pump();

    expect(log, equals(<int>[3]));
    log.clear();
  });

  testWidgets('Inherited widget notifies descendants when descendant previously failed to find a match', (WidgetTester tester) async {
    int? inheritedValue = -1;

    final Widget inner = Container(
      key: GlobalKey(),
      child: Builder(
        builder: (BuildContext context) {
          final ValueInherited? widget = context.dependOnInheritedWidgetOfExactType<ValueInherited>();
          inheritedValue = widget?.value;
          return Container();
        },
      ),
    );

    await tester.pumpWidget(
      inner,
    );
    expect(inheritedValue, isNull);

    inheritedValue = -2;
    await tester.pumpWidget(
      ValueInherited(
        value: 3,
        child: inner,
      ),
    );
    expect(inheritedValue, equals(3));
  });

  testWidgets("Inherited widget doesn't notify descendants when descendant did not previously fail to find a match and had no dependencies", (WidgetTester tester) async {
    int buildCount = 0;

    final Widget inner = Container(
      key: GlobalKey(),
      child: Builder(
        builder: (BuildContext context) {
          buildCount += 1;
          return Container();
        },
      ),
    );

    await tester.pumpWidget(
      inner,
    );
    expect(buildCount, equals(1));

    await tester.pumpWidget(
      ValueInherited(
        value: 3,
        child: inner,
      ),
    );
    expect(buildCount, equals(1));
  });

  testWidgets('Inherited widget does notify descendants when descendant did not previously fail to find a match but did have other dependencies', (WidgetTester tester) async {
    int buildCount = 0;

    final Widget inner = Container(
      key: GlobalKey(),
      child: TestInherited(
        shouldNotify: false,
        child: Builder(
          builder: (BuildContext context) {
            context.dependOnInheritedWidgetOfExactType<TestInherited>();
            buildCount += 1;
            return Container();
          },
        ),
      ),
    );

    await tester.pumpWidget(
      inner,
    );
    expect(buildCount, equals(1));

    await tester.pumpWidget(
      ValueInherited(
        value: 3,
        child: inner,
      ),
    );
    expect(buildCount, equals(2));
  });

  testWidgets('initState() dependency on Inherited asserts', (WidgetTester tester) async {
    // This is a regression test for https://github.com/flutter/flutter/issues/5491
    bool exceptionCaught = false;

    final TestInherited parent = TestInherited(child: ExpectFail(() {
      exceptionCaught = true;
    }));
    await tester.pumpWidget(parent);

    expect(exceptionCaught, isTrue);
  });

  testWidgets('InheritedNotifier', (WidgetTester tester) async {
    int buildCount = 0;
    final ChangeNotifier notifier = ChangeNotifier();

    final Widget builder = Builder(
      builder: (BuildContext context) {
        context.dependOnInheritedWidgetOfExactType<ChangeNotifierInherited>();
        buildCount += 1;
        return Container();
      },
    );

    final Widget inner = ChangeNotifierInherited(
      notifier: notifier,
      child: builder,
    );
    await tester.pumpWidget(inner);
    expect(buildCount, equals(1));

    await tester.pumpWidget(inner);
    expect(buildCount, equals(1));

    await tester.pump();
    expect(buildCount, equals(1));

    notifier.notifyListeners();
    await tester.pump();
    expect(buildCount, equals(2));

    await tester.pumpWidget(inner);
    expect(buildCount, equals(2));

    await tester.pumpWidget(ChangeNotifierInherited(
      child: builder,
    ));
    expect(buildCount, equals(3));
  });
}