packages/flutter/test/widgets/layout_builder_mutations_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/src/rendering/sliver.dart';
import 'package:flutter/src/widgets/basic.dart';
import 'package:flutter/src/widgets/framework.dart';
import 'package:flutter/src/widgets/layout_builder.dart';
import 'package:flutter/src/widgets/scroll_view.dart';
import 'package:flutter/src/widgets/sliver_layout_builder.dart';
import 'package:flutter_test/flutter_test.dart';

class Wrapper extends StatelessWidget {
  const Wrapper({
    Key? key,
    required this.child,
  }) : assert(child != null),
       super(key: key);

  final Widget child;

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

void main() {
  testWidgets('Moving a global key from another LayoutBuilder at layout time', (WidgetTester tester) async {
    final GlobalKey victimKey = GlobalKey();

    await tester.pumpWidget(Row(
      textDirection: TextDirection.ltr,
      children: <Widget>[
        Wrapper(
          child: LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
            return const SizedBox();
          }),
        ),
        Wrapper(
          child: Wrapper(
            child: LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
              return Wrapper(
                child: SizedBox(key: victimKey),
              );
            }),
          ),
        ),
      ],
    ));

    await tester.pumpWidget(Row(
      textDirection: TextDirection.ltr,
      children: <Widget>[
        Wrapper(
          child: LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
            return Wrapper(
              child: SizedBox(key: victimKey),
            );
          }),
        ),
        Wrapper(
          child: Wrapper(
            child: LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
              return const SizedBox();
            }),
          ),
        ),
      ],
    ));

    expect(tester.takeException(), null);
  });

  testWidgets('Moving a global key from another SliverLayoutBuilder at layout time', (WidgetTester tester) async {
    final GlobalKey victimKey1 = GlobalKey();
    final GlobalKey victimKey2 = GlobalKey();

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: CustomScrollView(
          slivers: <Widget>[
            SliverLayoutBuilder(
              builder: (BuildContext context, SliverConstraints constraint) {
                return SliverPadding(key: victimKey1, padding: const EdgeInsets.fromLTRB(1, 2, 3, 4));
              },
            ),
            SliverLayoutBuilder(
              builder: (BuildContext context, SliverConstraints constraint) {
                return SliverPadding(key: victimKey2, padding: const EdgeInsets.fromLTRB(5, 7, 11, 13));
              },
            ),
            SliverLayoutBuilder(
              builder: (BuildContext context, SliverConstraints constraint) {
                return const SliverPadding(padding: EdgeInsets.fromLTRB(5, 7, 11, 13));
              },
            ),
          ],
        ),
      ),
    );

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: CustomScrollView(
          slivers: <Widget>[
            SliverLayoutBuilder(
              builder: (BuildContext context, SliverConstraints constraint) {
                return SliverPadding(key: victimKey2, padding: const EdgeInsets.fromLTRB(1, 2, 3, 4));
              },
            ),
            SliverLayoutBuilder(
              builder: (BuildContext context, SliverConstraints constraint) {
                return const SliverPadding(padding: EdgeInsets.fromLTRB(5, 7, 11, 13));
              },
            ),
            SliverLayoutBuilder(
              builder: (BuildContext context, SliverConstraints constraint) {
                return SliverPadding(key: victimKey1, padding: const EdgeInsets.fromLTRB(5, 7, 11, 13));
              },
            ),
          ],
        ),
      ),
    );

    expect(tester.takeException(), null);
  });
}