// 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/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  final GlobalKey widgetKey = GlobalKey();
  Future<BuildContext> setupWidget(WidgetTester tester) async {
    await tester.pumpWidget(Container(key: widgetKey));
    return widgetKey.currentContext;
  }

  group(FocusNode, () {
    testWidgets('Can add children.', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusNode parent = FocusNode();
      final FocusAttachment parentAttachment = parent.attach(context);
      final FocusNode child1 = FocusNode();
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode();
      final FocusAttachment child2Attachment = child2.attach(context);
      parentAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      child1Attachment.reparent(parent: parent);
      expect(child1.parent, equals(parent));
      expect(parent.children.first, equals(child1));
      expect(parent.children.last, equals(child1));
      child2Attachment.reparent(parent: parent);
      expect(child1.parent, equals(parent));
      expect(child2.parent, equals(parent));
      expect(parent.children.first, equals(child1));
      expect(parent.children.last, equals(child2));
    });
    testWidgets('Can remove children.', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusNode parent = FocusNode();
      final FocusAttachment parentAttachment = parent.attach(context);
      final FocusNode child1 = FocusNode();
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode();
      final FocusAttachment child2Attachment = child2.attach(context);
      parentAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      child1Attachment.reparent(parent: parent);
      child2Attachment.reparent(parent: parent);
      expect(child1.parent, equals(parent));
      expect(child2.parent, equals(parent));
      expect(parent.children.first, equals(child1));
      expect(parent.children.last, equals(child2));
      child1Attachment.detach();
      expect(child1.parent, isNull);
      expect(child2.parent, equals(parent));
      expect(parent.children.first, equals(child2));
      expect(parent.children.last, equals(child2));
      child2Attachment.detach();
      expect(child1.parent, isNull);
      expect(child2.parent, isNull);
      expect(parent.children, isEmpty);
    });
    testWidgets('implements debugFillProperties', (WidgetTester tester) async {
      final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
      FocusNode(
        debugLabel: 'Label',
      ).debugFillProperties(builder);
      final List<String> description = builder.properties.map((DiagnosticsNode n) => n.toString()).toList();
      expect(description, <String>[
        'context: null',
        'canRequestFocus: true',
        'hasFocus: false',
        'hasPrimaryFocus: false'
      ]);
    });
  });
  group(FocusScopeNode, () {
    testWidgets('Can setFirstFocus on a scope with no manager.', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode(debugLabel: 'Scope');
      scope.attach(context);
      final FocusScopeNode parent = FocusScopeNode(debugLabel: 'Parent');
      parent.attach(context);
      final FocusScopeNode child1 = FocusScopeNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusScopeNode child2 = FocusScopeNode(debugLabel: 'Child 2');
      child2.attach(context);
      scope.setFirstFocus(parent);
      parent.setFirstFocus(child1);
      parent.setFirstFocus(child2);
      child1.requestFocus();
      await tester.pump();
      expect(scope.hasFocus, isFalse);
      expect(child1.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(scope.focusedChild, equals(parent));
      expect(parent.focusedChild, equals(child1));
      child1Attachment.detach();
      expect(scope.hasFocus, isFalse);
      expect(scope.focusedChild, equals(parent));
    });
    testWidgets('Removing a node removes it from scope.', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode();
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode parent = FocusNode();
      final FocusAttachment parentAttachment = parent.attach(context);
      final FocusNode child1 = FocusNode();
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode();
      final FocusAttachment child2Attachment = child2.attach(context);
      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      parentAttachment.reparent(parent: scope);
      child1Attachment.reparent(parent: parent);
      child2Attachment.reparent(parent: parent);
      child1.requestFocus();
      await tester.pump();
      expect(scope.hasFocus, isTrue);
      expect(child1.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(scope.focusedChild, equals(child1));
      child1Attachment.detach();
      expect(scope.hasFocus, isFalse);
      expect(scope.focusedChild, isNull);
    });
    testWidgets('Can add children to scope and focus', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode();
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode parent = FocusNode();
      final FocusAttachment parentAttachment = parent.attach(context);
      final FocusNode child1 = FocusNode();
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode();
      final FocusAttachment child2Attachment = child2.attach(context);
      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      parentAttachment.reparent(parent: scope);
      child1Attachment.reparent(parent: parent);
      child2Attachment.reparent(parent: parent);
      expect(scope.children.first, equals(parent));
      expect(parent.parent, equals(scope));
      expect(child1.parent, equals(parent));
      expect(child2.parent, equals(parent));
      expect(parent.children.first, equals(child1));
      expect(parent.children.last, equals(child2));
      child1.requestFocus();
      await tester.pump();
      expect(scope.focusedChild, equals(child1));
      expect(parent.hasFocus, isTrue);
      expect(parent.hasPrimaryFocus, isFalse);
      expect(child1.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(child2.hasFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);
      child2.requestFocus();
      await tester.pump();
      expect(scope.focusedChild, equals(child2));
      expect(parent.hasFocus, isTrue);
      expect(parent.hasPrimaryFocus, isFalse);
      expect(child1.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasFocus, isTrue);
      expect(child2.hasPrimaryFocus, isTrue);
    });
    testWidgets('Requesting focus before adding to tree results in a request after adding', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode();
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode child = FocusNode();
      child.requestFocus();
      expect(child.hasPrimaryFocus, isFalse); // not attached yet.

      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      await tester.pump();
      expect(scope.focusedChild, isNull);
      expect(child.hasPrimaryFocus, isFalse); // not attached yet.

      final FocusAttachment childAttachment = child.attach(context);
      expect(child.hasPrimaryFocus, isFalse); // not parented yet.
      childAttachment.reparent(parent: scope);
      await tester.pump();
      expect(child.hasPrimaryFocus, isTrue); // now attached and parented, so focus finally happened.
    });
    testWidgets('Autofocus works.', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode(debugLabel: 'Scope');
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode parent = FocusNode(debugLabel: 'Parent');
      final FocusAttachment parentAttachment = parent.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'Child 2');
      final FocusAttachment child2Attachment = child2.attach(context);
      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      parentAttachment.reparent(parent: scope);
      child1Attachment.reparent(parent: parent);
      child2Attachment.reparent(parent: parent);

      scope.autofocus(child2);
      await tester.pump();

      expect(scope.focusedChild, equals(child2));
      expect(parent.hasFocus, isTrue);
      expect(child1.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasFocus, isTrue);
      expect(child2.hasPrimaryFocus, isTrue);
      child1.requestFocus();
      scope.autofocus(child2);

      await tester.pump();

      expect(scope.focusedChild, equals(child1));
      expect(parent.hasFocus, isTrue);
      expect(child1.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(child2.hasFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);
    });
    testWidgets('Adding a focusedChild to a scope sets scope as focusedChild in parent scope', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode();
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode();
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode child1 = FocusNode();
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode();
      final FocusAttachment child2Attachment = child2.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: scope1);
      child1Attachment.reparent(parent: scope1);
      child2Attachment.reparent(parent: scope2);
      child2.requestFocus();
      await tester.pump();
      expect(scope2.focusedChild, equals(child2));
      expect(scope1.focusedChild, equals(scope2));
      expect(child1.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasFocus, isTrue);
      expect(child2.hasPrimaryFocus, isTrue);
      child1.requestFocus();
      await tester.pump();
      expect(scope2.focusedChild, equals(child2));
      expect(scope1.focusedChild, equals(child1));
      expect(child1.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(child2.hasFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);
    });
    testWidgets('Can move node with focus without losing focus', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode(debugLabel: 'Scope');
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'Parent 1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'Parent 2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'Child 2');
      final FocusAttachment child2Attachment = child2.attach(context);
      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope);
      parent2Attachment.reparent(parent: scope);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      expect(scope.children.first, equals(parent1));
      expect(scope.children.last, equals(parent2));
      expect(parent1.parent, equals(scope));
      expect(parent2.parent, equals(scope));
      expect(child1.parent, equals(parent1));
      expect(child2.parent, equals(parent1));
      expect(parent1.children.first, equals(child1));
      expect(parent1.children.last, equals(child2));
      child1.requestFocus();
      await tester.pump();
      child1Attachment.reparent(parent: parent2);
      await tester.pump();

      expect(scope.focusedChild, equals(child1));
      expect(child1.parent, equals(parent2));
      expect(child2.parent, equals(parent1));
      expect(parent1.children.first, equals(child2));
      expect(parent2.children.first, equals(child1));
    });
    testWidgets('canRequestFocus affects children.', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode(debugLabel: 'Scope', canRequestFocus: true);
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'Parent 1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'Parent 2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'Child 2');
      final FocusAttachment child2Attachment = child2.attach(context);
      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope);
      parent2Attachment.reparent(parent: scope);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child1.requestFocus();
      await tester.pump();

      expect(tester.binding.focusManager.primaryFocus, equals(child1));
      expect(scope.focusedChild, equals(child1));
      expect(scope.traversalDescendants.contains(child1), isTrue);
      expect(scope.traversalDescendants.contains(child2), isTrue);

      scope.canRequestFocus = false;
      await tester.pump();
      child2.requestFocus();
      await tester.pump();
      expect(tester.binding.focusManager.primaryFocus, isNot(equals(child2)));
      expect(tester.binding.focusManager.primaryFocus, isNot(equals(child1)));
      expect(scope.focusedChild, equals(child1));
      expect(scope.traversalDescendants.contains(child1), isFalse);
      expect(scope.traversalDescendants.contains(child2), isFalse);
    });
    testWidgets("skipTraversal doesn't affect children.", (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope = FocusScopeNode(debugLabel: 'Scope', skipTraversal: false);
      final FocusAttachment scopeAttachment = scope.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'Parent 1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'Parent 2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'Child 2');
      final FocusAttachment child2Attachment = child2.attach(context);
      scopeAttachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope);
      parent2Attachment.reparent(parent: scope);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child1.requestFocus();
      await tester.pump();

      expect(tester.binding.focusManager.primaryFocus, equals(child1));
      expect(scope.focusedChild, equals(child1));
      expect(tester.binding.focusManager.rootScope.traversalDescendants.contains(scope), isTrue);
      expect(scope.traversalDescendants.contains(child1), isTrue);
      expect(scope.traversalDescendants.contains(child2), isTrue);

      scope.skipTraversal = true;
      await tester.pump();
      expect(tester.binding.focusManager.primaryFocus, equals(child1));
      expect(scope.focusedChild, equals(child1));
      expect(tester.binding.focusManager.rootScope.traversalDescendants.contains(scope), isFalse);
      expect(scope.traversalDescendants.contains(child1), isTrue);
      expect(scope.traversalDescendants.contains(child2), isTrue);
    });
    testWidgets('Can move node between scopes and lose scope focus', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'scope1')..attach(context);
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'scope2');
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'parent1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'parent2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'child1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'child2');
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'child3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'child4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);

      child1.requestFocus();
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(parent2.children.contains(child1), isFalse);

      child1Attachment.reparent(parent: parent2);
      await tester.pump();
      expect(scope1.focusedChild, isNull);
      expect(parent2.children.contains(child1), isTrue);
    });
    testWidgets('ancestors and descendants are computed and recomputed properly', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'scope1');
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'scope2');
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'parent1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'parent2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'child1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'child2');
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'child3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'child4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);
      child4.requestFocus();
      await tester.pump();
      expect(child4.ancestors, equals(<FocusNode>[parent2, scope2, tester.binding.focusManager.rootScope]));
      expect(tester.binding.focusManager.rootScope.descendants, equals(<FocusNode>[child1, child2, parent1, scope1, child3, child4, parent2, scope2]));
      scope2Attachment.reparent(parent: child2);
      await tester.pump();
      expect(child4.ancestors, equals(<FocusNode>[parent2, scope2, child2, parent1, scope1, tester.binding.focusManager.rootScope]));
      expect(tester.binding.focusManager.rootScope.descendants, equals(<FocusNode>[child1, child3, child4, parent2, scope2, child2, parent1, scope1]));
    });
    testWidgets('Can move focus between scopes and keep focus', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode();
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode();
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode();
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode();
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode();
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode();
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode();
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode();
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);
      child4.requestFocus();
      await tester.pump();
      child1.requestFocus();
      await tester.pump();
      expect(child4.hasFocus, isFalse);
      expect(child4.hasPrimaryFocus, isFalse);
      expect(child1.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(scope1.hasFocus, isTrue);
      expect(scope1.hasPrimaryFocus, isFalse);
      expect(scope2.hasFocus, isFalse);
      expect(scope2.hasPrimaryFocus, isFalse);
      expect(parent1.hasFocus, isTrue);
      expect(parent2.hasFocus, isFalse);
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child4));
      scope2.requestFocus();
      await tester.pump();
      expect(child4.hasFocus, isTrue);
      expect(child4.hasPrimaryFocus, isTrue);
      expect(child1.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(scope1.hasFocus, isFalse);
      expect(scope1.hasPrimaryFocus, isFalse);
      expect(scope2.hasFocus, isTrue);
      expect(scope2.hasPrimaryFocus, isFalse);
      expect(parent1.hasFocus, isFalse);
      expect(parent2.hasFocus, isTrue);
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child4));
    });
    testWidgets('Unfocus with disposition previouslyFocusedChild works properly', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'scope1')..attach(context);
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'scope2');
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'parent1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'parent2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'child1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'child2');
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'child3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'child4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);

      // Build up a history.
      child4.requestFocus();
      await tester.pump();
      child2.requestFocus();
      await tester.pump();
      child3.requestFocus();
      await tester.pump();
      child1.requestFocus();
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));

      child1.unfocus(disposition: UnfocusDisposition.previouslyFocusedChild);
      await tester.pump();
      expect(scope1.focusedChild, equals(child2));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasFocus, isTrue);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasPrimaryFocus, isTrue);

      // Can re-focus child.
      child1.requestFocus();
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasFocus, isTrue);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(child3.hasPrimaryFocus, isFalse);

      // The same thing happens when unfocusing a second time.
      child1.unfocus(disposition: UnfocusDisposition.previouslyFocusedChild);
      await tester.pump();
      expect(scope1.focusedChild, equals(child2));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasFocus, isTrue);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasPrimaryFocus, isTrue);

      // When the scope gets unfocused, then the sibling scope gets focus.
      child1.requestFocus();
      await tester.pump();
      scope1.unfocus(disposition: UnfocusDisposition.previouslyFocusedChild);
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasFocus, isFalse);
      expect(scope2.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child3.hasPrimaryFocus, isTrue);
    });
    testWidgets('Unfocus with disposition scope works properly', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'scope1')..attach(context);
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'scope2');
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'parent1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'parent2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'child1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'child2');
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'child3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'child4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);

      // Build up a history.
      child4.requestFocus();
      await tester.pump();
      child2.requestFocus();
      await tester.pump();
      child3.requestFocus();
      await tester.pump();
      child1.requestFocus();
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));

      child1.unfocus(disposition: UnfocusDisposition.scope);
      await tester.pump();
      // Focused child doesn't change.
      expect(scope1.focusedChild, isNull);
      expect(scope2.focusedChild, equals(child3));
      // Focus does change.
      expect(scope1.hasPrimaryFocus, isTrue);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);

      // Can re-focus child.
      child1.requestFocus();
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasFocus, isTrue);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isTrue);
      expect(child3.hasPrimaryFocus, isFalse);

      // The same thing happens when unfocusing a second time.
      child1.unfocus(disposition: UnfocusDisposition.scope);
      await tester.pump();
      expect(scope1.focusedChild, isNull);
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasPrimaryFocus, isTrue);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);

      // When the scope gets unfocused, then its parent scope (the root scope)
      // gets focus, but it doesn't mess with the focused children.
      child1.requestFocus();
      await tester.pump();
      scope1.unfocus(disposition: UnfocusDisposition.scope);
      await tester.pump();
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasFocus, isFalse);
      expect(scope2.hasFocus, isFalse);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child3.hasPrimaryFocus, isFalse);
      expect(FocusManager.instance.rootScope.hasPrimaryFocus, isTrue);
    });
    testWidgets('Unfocus works properly when some nodes are unfocusable', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'scope1')..attach(context);
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'scope2');
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'parent1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'parent2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'child1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'child2');
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'child3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'child4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);

      // Build up a history.
      child4.requestFocus();
      await tester.pump();
      child2.requestFocus();
      await tester.pump();
      child3.requestFocus();
      await tester.pump();
      child1.requestFocus();
      await tester.pump();
      expect(child1.hasPrimaryFocus, isTrue);

      scope1.canRequestFocus = false;
      await tester.pump();

      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(child3.hasPrimaryFocus, isTrue);

      child1.unfocus(disposition: UnfocusDisposition.scope);
      await tester.pump();
      expect(child3.hasPrimaryFocus, isTrue);
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasPrimaryFocus, isFalse);
      expect(scope2.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);

      child1.unfocus(disposition: UnfocusDisposition.previouslyFocusedChild);
      await tester.pump();
      expect(child3.hasPrimaryFocus, isTrue);
      expect(scope1.focusedChild, equals(child1));
      expect(scope2.focusedChild, equals(child3));
      expect(scope1.hasPrimaryFocus, isFalse);
      expect(scope2.hasFocus, isTrue);
      expect(child1.hasPrimaryFocus, isFalse);
      expect(child2.hasPrimaryFocus, isFalse);
    });
    testWidgets('Requesting focus on a scope works properly when some focusedChild nodes are unfocusable', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'scope1')..attach(context);
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'scope2');
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'parent1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'parent2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'child1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(debugLabel: 'child2');
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'child3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'child4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);

      // Build up a history.
      child4.requestFocus();
      await tester.pump();
      child2.requestFocus();
      await tester.pump();
      child3.requestFocus();
      await tester.pump();
      child1.requestFocus();
      await tester.pump();
      expect(child1.hasPrimaryFocus, isTrue);

      child1.canRequestFocus = false;
      child3.canRequestFocus = false;
      await tester.pump();
      scope1.requestFocus();
      await tester.pump();

      expect(scope1.focusedChild, equals(child2));
      expect(child2.hasPrimaryFocus, isTrue);

      scope2.requestFocus();
      await tester.pump();

      expect(scope2.focusedChild, equals(child4));
      expect(child4.hasPrimaryFocus, isTrue);
    });
    testWidgets('Key handling bubbles up and terminates when handled.', (WidgetTester tester) async {
      final Set<FocusNode> receivedAnEvent = <FocusNode>{};
      final Set<FocusNode> shouldHandle = <FocusNode>{};
      bool handleEvent(FocusNode node, RawKeyEvent event) {
        if (shouldHandle.contains(node)) {
          receivedAnEvent.add(node);
          return true;
        }
        return false;
      }

      Future<void> sendEvent() async {
        receivedAnEvent.clear();
        await tester.sendKeyEvent(LogicalKeyboardKey.metaLeft, platform: 'fuchsia');
      }

      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'Scope 1');
      final FocusAttachment scope1Attachment = scope1.attach(context, onKey: handleEvent);
      final FocusScopeNode scope2 = FocusScopeNode(debugLabel: 'Scope 2');
      final FocusAttachment scope2Attachment = scope2.attach(context, onKey: handleEvent);
      final FocusNode parent1 = FocusNode(debugLabel: 'Parent 1', onKey: handleEvent);
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'Parent 2', onKey: handleEvent);
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context, onKey: handleEvent);
      final FocusNode child2 = FocusNode(debugLabel: 'Child 2');
      final FocusAttachment child2Attachment = child2.attach(context, onKey: handleEvent);
      final FocusNode child3 = FocusNode(debugLabel: 'Child 3');
      final FocusAttachment child3Attachment = child3.attach(context, onKey: handleEvent);
      final FocusNode child4 = FocusNode(debugLabel: 'Child 4');
      final FocusAttachment child4Attachment = child4.attach(context, onKey: handleEvent);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);
      child4.requestFocus();
      await tester.pump();
      shouldHandle.addAll(<FocusNode>{scope2, parent2, child2, child4});
      await sendEvent();
      expect(receivedAnEvent, equals(<FocusNode>{child4}));
      shouldHandle.remove(child4);
      await sendEvent();
      expect(receivedAnEvent, equals(<FocusNode>{parent2}));
      shouldHandle.remove(parent2);
      await sendEvent();
      expect(receivedAnEvent, equals(<FocusNode>{scope2}));
      shouldHandle.clear();
      await sendEvent();
      expect(receivedAnEvent, isEmpty);
      child1.requestFocus();
      await tester.pump();
      shouldHandle.addAll(<FocusNode>{scope2, parent2, child2, child4});
      await sendEvent();
      // Since none of the focused nodes handle this event, nothing should
      // receive it.
      expect(receivedAnEvent, isEmpty);
    });
    testWidgets('Events change focus highlight mode.', (WidgetTester tester) async {
      await setupWidget(tester);
      int callCount = 0;
      FocusHighlightMode lastMode;
      void handleModeChange(FocusHighlightMode mode) {
        lastMode = mode;
        callCount++;
      }

      FocusManager.instance.addHighlightModeListener(handleModeChange);
      addTearDown(() => FocusManager.instance.removeHighlightModeListener(handleModeChange));
      expect(callCount, equals(0));
      expect(lastMode, isNull);
      FocusManager.instance.highlightStrategy = FocusHighlightStrategy.automatic;
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.touch));
      await tester.sendKeyEvent(LogicalKeyboardKey.metaLeft, platform: 'fuchsia');
      expect(callCount, equals(1));
      expect(lastMode, FocusHighlightMode.traditional);
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.traditional));
      await tester.tap(find.byType(Container));
      expect(callCount, equals(2));
      expect(lastMode, FocusHighlightMode.touch);
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.touch));
      final TestGesture gesture = await tester.startGesture(Offset.zero, kind: PointerDeviceKind.mouse);
      addTearDown(gesture.removePointer);
      await gesture.up();
      expect(callCount, equals(3));
      expect(lastMode, FocusHighlightMode.traditional);
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.traditional));
      await tester.tap(find.byType(Container));
      expect(callCount, equals(4));
      expect(lastMode, FocusHighlightMode.touch);
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.touch));
      FocusManager.instance.highlightStrategy = FocusHighlightStrategy.alwaysTraditional;
      expect(callCount, equals(5));
      expect(lastMode, FocusHighlightMode.traditional);
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.traditional));
      FocusManager.instance.highlightStrategy = FocusHighlightStrategy.alwaysTouch;
      expect(callCount, equals(6));
      expect(lastMode, FocusHighlightMode.touch);
      expect(FocusManager.instance.highlightMode, equals(FocusHighlightMode.touch));
    });
    testWidgets('implements debugFillProperties', (WidgetTester tester) async {
      final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
      FocusScopeNode(
        debugLabel: 'Scope Label',
      ).debugFillProperties(builder);
      final List<String> description = builder.properties.map((DiagnosticsNode n) => n.toString()).toList();
      expect(description, <String>[
        'context: null',
        'canRequestFocus: true',
        'hasFocus: false',
        'hasPrimaryFocus: false'
      ]);
    });
    testWidgets('debugDescribeFocusTree produces correct output', (WidgetTester tester) async {
      final BuildContext context = await setupWidget(tester);
      final FocusScopeNode scope1 = FocusScopeNode(debugLabel: 'Scope 1');
      final FocusAttachment scope1Attachment = scope1.attach(context);
      final FocusScopeNode scope2 = FocusScopeNode(); // No label, Just to test that it works.
      final FocusAttachment scope2Attachment = scope2.attach(context);
      final FocusNode parent1 = FocusNode(debugLabel: 'Parent 1');
      final FocusAttachment parent1Attachment = parent1.attach(context);
      final FocusNode parent2 = FocusNode(debugLabel: 'Parent 2');
      final FocusAttachment parent2Attachment = parent2.attach(context);
      final FocusNode child1 = FocusNode(debugLabel: 'Child 1');
      final FocusAttachment child1Attachment = child1.attach(context);
      final FocusNode child2 = FocusNode(); // No label, Just to test that it works.
      final FocusAttachment child2Attachment = child2.attach(context);
      final FocusNode child3 = FocusNode(debugLabel: 'Child 3');
      final FocusAttachment child3Attachment = child3.attach(context);
      final FocusNode child4 = FocusNode(debugLabel: 'Child 4');
      final FocusAttachment child4Attachment = child4.attach(context);
      scope1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      scope2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
      parent1Attachment.reparent(parent: scope1);
      parent2Attachment.reparent(parent: scope2);
      child1Attachment.reparent(parent: parent1);
      child2Attachment.reparent(parent: parent1);
      child3Attachment.reparent(parent: parent2);
      child4Attachment.reparent(parent: parent2);
      child4.requestFocus();
      await tester.pump();
      final String description = debugDescribeFocusTree();
      expect(
        description,
        equalsIgnoringHashCodes(
          'FocusManager#00000\n'
          ' │ primaryFocus: FocusNode#00000(Child 4 [PRIMARY FOCUS])\n'
          ' │ primaryFocusCreator: Container-[GlobalKey#00000] ← [root]\n'
          ' │\n'
          ' └─rootScope: FocusScopeNode#00000(Root Focus Scope [IN FOCUS PATH])\n'
          '   │ IN FOCUS PATH\n'
          '   │ focusedChildren: FocusScopeNode#00000([IN FOCUS PATH])\n'
          '   │\n'
          '   ├─Child 1: FocusScopeNode#00000(Scope 1)\n'
          '   │ │ context: Container-[GlobalKey#00000]\n'
          '   │ │\n'
          '   │ └─Child 1: FocusNode#00000(Parent 1)\n'
          '   │   │ context: Container-[GlobalKey#00000]\n'
          '   │   │\n'
          '   │   ├─Child 1: FocusNode#00000(Child 1)\n'
          '   │   │   context: Container-[GlobalKey#00000]\n'
          '   │   │\n'
          '   │   └─Child 2: FocusNode#00000\n'
          '   │       context: Container-[GlobalKey#00000]\n'
          '   │\n'
          '   └─Child 2: FocusScopeNode#00000([IN FOCUS PATH])\n'
          '     │ context: Container-[GlobalKey#00000]\n'
          '     │ IN FOCUS PATH\n'
          '     │ focusedChildren: FocusNode#00000(Child 4 [PRIMARY FOCUS])\n'
          '     │\n'
          '     └─Child 1: FocusNode#00000(Parent 2 [IN FOCUS PATH])\n'
          '       │ context: Container-[GlobalKey#00000]\n'
          '       │ IN FOCUS PATH\n'
          '       │\n'
          '       ├─Child 1: FocusNode#00000(Child 3)\n'
          '       │   context: Container-[GlobalKey#00000]\n'
          '       │\n'
          '       └─Child 2: FocusNode#00000(Child 4 [PRIMARY FOCUS])\n'
          '           context: Container-[GlobalKey#00000]\n'
          '           PRIMARY FOCUS\n'
        ));
    });
  });
  testWidgets("Doesn't lose focused child when reparenting if the nearestScope doesn't change.", (WidgetTester tester) async {
    final BuildContext context = await setupWidget(tester);
    final FocusScopeNode parent1 = FocusScopeNode(debugLabel: 'parent1');
    final FocusScopeNode parent2 = FocusScopeNode(debugLabel: 'parent2');
    final FocusAttachment parent1Attachment = parent1.attach(context);
    final FocusAttachment parent2Attachment = parent2.attach(context);
    final FocusNode child1 = FocusNode(debugLabel: 'child1');
    final FocusAttachment child1Attachment = child1.attach(context);
    final FocusNode child2 = FocusNode(debugLabel: 'child2');
    final FocusAttachment child2Attachment = child2.attach(context);
    parent1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
    child1Attachment.reparent(parent: parent1);
    child2Attachment.reparent(parent: child1);
    parent1.autofocus(child2);
    await tester.pump();
    parent2Attachment.reparent(parent: tester.binding.focusManager.rootScope);
    parent2.requestFocus();
    await tester.pump();
    expect(parent1.focusedChild, equals(child2));
    child2Attachment.reparent(parent: parent1);
    expect(parent1.focusedChild, equals(child2));
    parent1.requestFocus();
    await tester.pump();
    expect(parent1.focusedChild, equals(child2));
  });
  testWidgets('Ancestors get notified exactly as often as needed if focused child changes focus.', (WidgetTester tester) async {
    bool topFocus = false;
    bool parent1Focus = false;
    bool parent2Focus = false;
    bool child1Focus = false;
    bool child2Focus = false;
    int topNotify = 0;
    int parent1Notify = 0;
    int parent2Notify = 0;
    int child1Notify = 0;
    int child2Notify = 0;
    void clear() {
      topFocus = false;
      parent1Focus = false;
      parent2Focus = false;
      child1Focus = false;
      child2Focus = false;
      topNotify = 0;
      parent1Notify = 0;
      parent2Notify = 0;
      child1Notify = 0;
      child2Notify = 0;
    }
    final BuildContext context = await setupWidget(tester);
    final FocusScopeNode top = FocusScopeNode(debugLabel: 'top');
    final FocusAttachment topAttachment = top.attach(context);
    final FocusScopeNode parent1 = FocusScopeNode(debugLabel: 'parent1');
    final FocusAttachment parent1Attachment = parent1.attach(context);
    final FocusScopeNode parent2 = FocusScopeNode(debugLabel: 'parent2');
    final FocusAttachment parent2Attachment = parent2.attach(context);
    final FocusNode child1 = FocusNode(debugLabel: 'child1');
    final FocusAttachment child1Attachment = child1.attach(context);
    final FocusNode child2 = FocusNode(debugLabel: 'child2');
    final FocusAttachment child2Attachment = child2.attach(context);
    topAttachment.reparent(parent: tester.binding.focusManager.rootScope);
    parent1Attachment.reparent(parent: top);
    parent2Attachment.reparent(parent: top);
    child1Attachment.reparent(parent: parent1);
    child2Attachment.reparent(parent: parent2);
    top.addListener(() {
      topNotify++;
      topFocus = top.hasFocus;
    });
    parent1.addListener(() {
      parent1Notify++;
      parent1Focus = parent1.hasFocus;
    });
    parent2.addListener(() {
      parent2Notify++;
      parent2Focus = parent2.hasFocus;
    });
    child1.addListener(() {
      child1Notify++;
      child1Focus = child1.hasFocus;
    });
    child2.addListener(() {
      child2Notify++;
      child2Focus = child2.hasFocus;
    });
    child1.requestFocus();
    await tester.pump();
    expect(topFocus, isTrue);
    expect(parent1Focus, isTrue);
    expect(child1Focus, isTrue);
    expect(parent2Focus, isFalse);
    expect(child2Focus, isFalse);
    expect(topNotify, equals(1));
    expect(parent1Notify, equals(1));
    expect(child1Notify, equals(1));
    expect(parent2Notify, equals(0));
    expect(child2Notify, equals(0));

    clear();
    child1.unfocus();
    await tester.pump();
    expect(topFocus, isFalse);
    expect(parent1Focus, isTrue);
    expect(child1Focus, isFalse);
    expect(parent2Focus, isFalse);
    expect(child2Focus, isFalse);
    expect(topNotify, equals(0));
    expect(parent1Notify, equals(1));
    expect(child1Notify, equals(1));
    expect(parent2Notify, equals(0));
    expect(child2Notify, equals(0));

    clear();
    child1.requestFocus();
    await tester.pump();
    expect(topFocus, isFalse);
    expect(parent1Focus, isTrue);
    expect(child1Focus, isTrue);
    expect(parent2Focus, isFalse);
    expect(child2Focus, isFalse);
    expect(topNotify, equals(0));
    expect(parent1Notify, equals(1));
    expect(child1Notify, equals(1));
    expect(parent2Notify, equals(0));
    expect(child2Notify, equals(0));

    clear();
    child2.requestFocus();
    await tester.pump();
    expect(topFocus, isFalse);
    expect(parent1Focus, isFalse);
    expect(child1Focus, isFalse);
    expect(parent2Focus, isTrue);
    expect(child2Focus, isTrue);
    expect(topNotify, equals(0));
    expect(parent1Notify, equals(1));
    expect(child1Notify, equals(1));
    expect(parent2Notify, equals(1));
    expect(child2Notify, equals(1));

    // Changing the focus back before the pump shouldn't cause notifications.
    clear();
    child1.requestFocus();
    child2.requestFocus();
    await tester.pump();
    expect(topFocus, isFalse);
    expect(parent1Focus, isFalse);
    expect(child1Focus, isFalse);
    expect(parent2Focus, isFalse);
    expect(child2Focus, isFalse);
    expect(topNotify, equals(0));
    expect(parent1Notify, equals(0));
    expect(child1Notify, equals(0));
    expect(parent2Notify, equals(0));
    expect(child2Notify, equals(0));
  });
  testWidgets('Focus changes notify listeners.', (WidgetTester tester) async {
    final BuildContext context = await setupWidget(tester);
    final FocusScopeNode parent1 = FocusScopeNode(debugLabel: 'parent1');
    final FocusAttachment parent1Attachment = parent1.attach(context);
    final FocusNode child1 = FocusNode(debugLabel: 'child1');
    final FocusAttachment child1Attachment = child1.attach(context);
    final FocusNode child2 = FocusNode(debugLabel: 'child2');
    final FocusAttachment child2Attachment = child2.attach(context);
    parent1Attachment.reparent(parent: tester.binding.focusManager.rootScope);
    child1Attachment.reparent(parent: parent1);
    child2Attachment.reparent(parent: child1);

    int notifyCount = 0;
    void handleFocusChange() {
      notifyCount++;
    }
    tester.binding.focusManager.addListener(handleFocusChange);

    parent1.autofocus(child2);
    expect(notifyCount, equals(0));
    await tester.pump();
    expect(notifyCount, equals(1));
    notifyCount = 0;

    child1.requestFocus();
    child2.requestFocus();
    child1.requestFocus();
    await tester.pump();
    expect(notifyCount, equals(1));
    notifyCount = 0;

    child2.requestFocus();
    await tester.pump();
    expect(notifyCount, equals(1));
    notifyCount = 0;

    child2.unfocus();
    await tester.pump();
    expect(notifyCount, equals(1));
    notifyCount = 0;

    tester.binding.focusManager.removeListener(handleFocusChange);
  });
  testWidgets('FocusManager notifies listeners when a widget loses focus because it was removed.', (WidgetTester tester) async {
    final FocusNode nodeA = FocusNode(debugLabel: 'a');
    final FocusNode nodeB = FocusNode(debugLabel: 'b');
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.rtl,
        child: Column(
          children: <Widget>[
            Focus(focusNode: nodeA , child: const Text('a')),
            Focus(focusNode: nodeB, child: const Text('b')),
          ],
        ),
      ),
    );
    int notifyCount = 0;
    void handleFocusChange() {
      notifyCount++;
    }
    tester.binding.focusManager.addListener(handleFocusChange);

    nodeA.requestFocus();
    await tester.pump();
    expect(nodeA.hasPrimaryFocus, isTrue);
    expect(notifyCount, equals(1));
    notifyCount = 0;

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.rtl,
        child: Column(
          children: <Widget>[
            Focus(focusNode: nodeB, child: const Text('b')),
          ],
        ),
      ),
    );

    await tester.pump();
    expect(nodeA.hasPrimaryFocus, isFalse);
    expect(nodeB.hasPrimaryFocus, isFalse);
    expect(notifyCount, equals(1));
    notifyCount = 0;

    tester.binding.focusManager.removeListener(handleFocusChange);
  });
}