Add ancestor and descendant finders to Driver (#32410)

packages/flutter_driver/lib/src/common/find.dart

@@ -148,6 +148,8 @@ abstract class SerializableFinder {
       case 'BySemanticsLabel': return BySemanticsLabel.deserialize(json);
       case 'ByText': return ByText.deserialize(json);
       case 'PageBack': return const PageBack();
+      case 'Descendant': return Descendant.deserialize(json);
+      case 'Ancestor': return Ancestor.deserialize(json);
     }
     throw DriverError('Unsupported search specification type $finderType');
   }
@@ -317,6 +319,120 @@ class PageBack extends SerializableFinder {
   String get finderType => 'PageBack';
 }
 
+/// A Flutter Driver finder that finds a descendant of [of] that matches
+/// [matching].
+///
+/// If the `matchRoot` argument is true, then the widget specified by [of] will
+/// be considered for a match. The argument defaults to false.
+class Descendant extends SerializableFinder {
+  /// Creates a descendant finder.
+  const Descendant({
+    @required this.of,
+    @required this.matching,
+    this.matchRoot = false,
+  });
+
+  /// The finder specifying the widget of which the descendant is to be found.
+  final SerializableFinder of;
+
+  /// Only a descendant of [of] matching this finder will be found.
+  final SerializableFinder matching;
+
+  /// Whether the widget matching [of] will be considered for a match.
+  final bool matchRoot;
+
+  @override
+  String get finderType => 'Descendant';
+
+  @override
+  Map<String, String> serialize() {
+    return super.serialize()
+        ..addAll(of.serialize().map((String key, String value) => MapEntry<String, String>('of_$key', value)))
+        ..addAll(matching.serialize().map((String key, String value) => MapEntry<String, String>('matching_$key', value)))
+        ..addAll(<String, String>{
+          'matchRoot': matchRoot ? 'true' : 'false',
+        });
+  }
+
+  /// Deserializes the finder from JSON generated by [serialize].
+  static Descendant deserialize(Map<String, String> json) {
+    final Map<String, String> of = <String, String>{};
+    final Map<String, String> matching = <String, String>{};
+    final Map<String, String> other = <String, String>{};
+    for (String key in json.keys) {
+      if (key.startsWith('of_')) {
+        of[key.substring('of_'.length)] = json[key];
+      } else if (key.startsWith('matching_')) {
+        matching[key.substring('matching_'.length)] = json[key];
+      } else {
+        other[key] = json[key];
+      }
+    }
+    return Descendant(
+      of: SerializableFinder.deserialize(of),
+      matching: SerializableFinder.deserialize(matching),
+      matchRoot: other['matchRoot'] == 'true',
+    );
+  }
+}
+
+/// A Flutter Driver finder that finds an ancestor of [of] that matches
+/// [matching].
+///
+/// If the `matchRoot` argument is true, then the widget specified by [of] will
+/// be considered for a match. The argument defaults to false.
+class Ancestor extends SerializableFinder {
+  /// Creates an ancestor finder.
+  const Ancestor({
+    @required this.of,
+    @required this.matching,
+    this.matchRoot = false,
+  });
+
+  /// The finder specifying the widget of which the ancestor is to be found.
+  final SerializableFinder of;
+
+  /// Only an ancestor of [of] matching this finder will be found.
+  final SerializableFinder matching;
+
+  /// Whether the widget matching [of] will be considered for a match.
+  final bool matchRoot;
+
+  @override
+  String get finderType => 'Ancestor';
+
+  @override
+  Map<String, String> serialize() {
+    return super.serialize()
+      ..addAll(of.serialize().map((String key, String value) => MapEntry<String, String>('of_$key', value)))
+      ..addAll(matching.serialize().map((String key, String value) => MapEntry<String, String>('matching_$key', value)))
+      ..addAll(<String, String>{
+        'matchRoot': matchRoot ? 'true' : 'false',
+      });
+  }
+
+  /// Deserializes the finder from JSON generated by [serialize].
+  static Ancestor deserialize(Map<String, String> json) {
+    final Map<String, String> of = <String, String>{};
+    final Map<String, String> matching = <String, String>{};
+    final Map<String, String> other = <String, String>{};
+    for (String key in json.keys) {
+      if (key.startsWith('of_')) {
+        of[key.substring('of_'.length)] = json[key];
+      } else if (key.startsWith('matching_')) {
+        matching[key.substring('matching_'.length)] = json[key];
+      } else {
+        other[key] = json[key];
+      }
+    }
+    return Ancestor(
+      of: SerializableFinder.deserialize(of),
+      matching: SerializableFinder.deserialize(matching),
+      matchRoot: other['matchRoot'] == 'true',
+    );
+  }
+}
+
 /// A Flutter driver command that retrieves a semantics id using a specified finder.
 ///
 /// This command requires assertions to be enabled on the device.

packages/flutter_driver/lib/src/driver/driver.dart

@@ -1017,6 +1017,28 @@ class CommonFinders {
 
   /// Finds the back button on a Material or Cupertino page's scaffold.
   SerializableFinder pageBack() => const PageBack();
+
+  /// Finds the widget that is an ancestor of the `of` parameter and that
+  /// matches the `matching` parameter.
+  ///
+  /// If the `matchRoot` argument is true then the widget specified by `of` will
+  /// be considered for a match. The argument defaults to false.
+  SerializableFinder ancestor({
+    @required SerializableFinder of,
+    @required SerializableFinder matching,
+    bool matchRoot = false,
+  }) => Ancestor(of: of, matching: matching, matchRoot: matchRoot);
+
+  /// Finds the widget that is an descendant of the `of` parameter and that
+  /// matches the `matching` parameter.
+  ///
+  /// If the `matchRoot` argument is true then the widget specified by `of` will
+  /// be considered for a match. The argument defaults to false.
+  SerializableFinder descendant({
+    @required SerializableFinder of,
+    @required SerializableFinder matching,
+    bool matchRoot = false,
+  }) => Descendant(of: of, matching: matching, matchRoot: matchRoot);
 }
 
 /// An immutable 2D floating-point offset used by Flutter Driver.

packages/flutter_driver/lib/src/extension/extension.dart

@@ -142,6 +142,8 @@ class FlutterDriverExtension {
       'ByValueKey': (SerializableFinder finder) => _createByValueKeyFinder(finder),
       'ByType': (SerializableFinder finder) => _createByTypeFinder(finder),
       'PageBack': (SerializableFinder finder) => _createPageBackFinder(),
+      'Ancestor': (SerializableFinder finder) => _createAncestorFinder(finder),
+      'Descendant': (SerializableFinder finder) => _createDescendantFinder(finder),
     });
   }
 
@@ -310,6 +312,22 @@ class FlutterDriverExtension {
     }, description: 'Material or Cupertino back button');
   }
 
+  Finder _createAncestorFinder(Ancestor arguments) {
+    return find.ancestor(
+      of: _createFinder(arguments.of),
+      matching: _createFinder(arguments.matching),
+      matchRoot: arguments.matchRoot,
+    );
+  }
+
+  Finder _createDescendantFinder(Descendant arguments) {
+    return find.descendant(
+      of: _createFinder(arguments.of),
+      matching: _createFinder(arguments.matching),
+      matchRoot: arguments.matchRoot,
+    );
+  }
+
   Finder _createFinder(SerializableFinder finder) {
     final FinderConstructor constructor = _finders[finder.finderType];
 

packages/flutter_driver/test/src/extension_test.dart

@@ -2,12 +2,15 @@
 // 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/rendering.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';
+import 'package:flutter_driver/flutter_driver.dart';
 import 'package:flutter_driver/src/common/find.dart';
 import 'package:flutter_driver/src/common/geometry.dart';
 import 'package:flutter_driver/src/common/request_data.dart';
+import 'package:flutter_driver/src/common/text.dart';
 import 'package:flutter_driver/src/extension/extension.dart';
 import 'package:flutter_test/flutter_test.dart';
 
@@ -151,4 +154,117 @@ void main() {
     expect(await getOffset(OffsetType.bottomRight), const Offset(40 + 100.0, 30 + 120.0));
     expect(await getOffset(OffsetType.center), const Offset(40 + (100 / 2), 30 + (120 / 2)));
   });
+
+  testWidgets('descendant finder', (WidgetTester tester) async {
+    flutterDriverLog.listen((LogRecord _) {}); // Silence logging.
+    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+
+    Future<String> getDescendantText({ String of, bool matchRoot = false}) async {
+      final Map<String, Object> arguments = GetText(Descendant(
+        of: ByValueKey(of),
+        matching: ByValueKey('text2'),
+        matchRoot: matchRoot,
+      ), timeout: const Duration(seconds: 1)).serialize();
+      final Map<String, dynamic> result = await extension.call(arguments);
+      if (result['isError']) {
+        return null;
+      }
+      return GetTextResult.fromJson(result['response']).text;
+    }
+
+    await tester.pumpWidget(
+        MaterialApp(
+            home: Column(
+              key: const ValueKey<String>('column'),
+              children: const <Widget>[
+                Text('Hello1', key: ValueKey<String>('text1')),
+                Text('Hello2', key: ValueKey<String>('text2')),
+                Text('Hello3', key: ValueKey<String>('text3')),
+              ],
+            )
+        )
+    );
+
+    expect(await getDescendantText(of: 'column'), 'Hello2');
+    expect(await getDescendantText(of: 'column', matchRoot: true), 'Hello2');
+    expect(await getDescendantText(of: 'text2', matchRoot: true), 'Hello2');
+
+    // Find nothing
+    Future<String> result = getDescendantText(of: 'text1', matchRoot: true);
+    await tester.pump(const Duration(seconds: 2));
+    expect(await result, null);
+
+    result = getDescendantText(of: 'text2');
+    await tester.pump(const Duration(seconds: 2));
+    expect(await result, null);
+  });
+
+  testWidgets('ancestor finder', (WidgetTester tester) async {
+    flutterDriverLog.listen((LogRecord _) {}); // Silence logging.
+    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+
+    Future<Offset> getAncestorTopLeft({ String of, String matching, bool matchRoot = false}) async {
+      final Map<String, Object> arguments = GetOffset(Ancestor(
+        of: ByValueKey(of),
+        matching: ByValueKey(matching),
+        matchRoot: matchRoot,
+      ), OffsetType.topLeft, timeout: const Duration(seconds: 1)).serialize();
+      final Map<String, dynamic> response = await extension.call(arguments);
+      if (response['isError']) {
+        return null;
+      }
+      final GetOffsetResult result = GetOffsetResult.fromJson(response['response']);
+      return Offset(result.dx, result.dy);
+    }
+
+    await tester.pumpWidget(
+        MaterialApp(
+          home: Center(
+              child: Container(
+                key: const ValueKey<String>('parent'),
+                height: 100,
+                width: 100,
+                child: Center(
+                  child: Row(
+                    children: <Widget>[
+                      Container(
+                        key: const ValueKey<String>('leftchild'),
+                        width: 25,
+                        height: 25,
+                      ),
+                      Container(
+                        key: const ValueKey<String>('righttchild'),
+                        width: 25,
+                        height: 25,
+                      ),
+                    ],
+                  ),
+                ),
+              )
+          ),
+        )
+    );
+
+    expect(
+      await getAncestorTopLeft(of: 'leftchild', matching: 'parent'),
+      const Offset((800 - 100) / 2, (600 - 100) / 2),
+    );
+    expect(
+      await getAncestorTopLeft(of: 'leftchild', matching: 'parent', matchRoot: true),
+      const Offset((800 - 100) / 2, (600 - 100) / 2),
+    );
+    expect(
+      await getAncestorTopLeft(of: 'parent', matching: 'parent', matchRoot: true),
+      const Offset((800 - 100) / 2, (600 - 100) / 2),
+    );
+
+    // Find nothing
+    Future<Offset> result = getAncestorTopLeft(of: 'leftchild', matching: 'leftchild');
+    await tester.pump(const Duration(seconds: 2));
+    expect(await result, null);
+
+    result = getAncestorTopLeft(of: 'leftchild', matching: 'righttchild');
+    await tester.pump(const Duration(seconds: 2));
+    expect(await result, null);
+  });
 }

packages/flutter_driver/test/src/find_test.dart

@@ -0,0 +1,83 @@
+// Copyright 2019 The Chromium 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_driver/src/common/find.dart';
+
+import '../common.dart';
+
+void main() {
+  test('Ancestor finder serialize', () {
+    const SerializableFinder of = ByType('Text');
+    final SerializableFinder matching = ByValueKey('hello');
+
+    final Ancestor a = Ancestor(
+      of: of,
+      matching: matching,
+      matchRoot: true,
+    );
+    expect(a.serialize(), <String, String>{
+      'finderType': 'Ancestor',
+      'of_finderType': 'ByType',
+      'of_type': 'Text',
+      'matching_finderType': 'ByValueKey',
+      'matching_keyValueString': 'hello',
+      'matching_keyValueType': 'String',
+      'matchRoot': 'true'
+    });
+  });
+
+  test('Ancestor finder deserialize', () {
+    final Map<String, String> serialized = <String, String>{
+      'finderType': 'Ancestor',
+      'of_finderType': 'ByType',
+      'of_type': 'Text',
+      'matching_finderType': 'ByValueKey',
+      'matching_keyValueString': 'hello',
+      'matching_keyValueType': 'String',
+      'matchRoot': 'true'
+    };
+
+    final Ancestor a = Ancestor.deserialize(serialized);
+    expect(a.of, isA<ByType>());
+    expect(a.matching, isA<ByValueKey>());
+    expect(a.matchRoot, isTrue);
+  });
+
+  test('Descendant finder serialize', () {
+    const SerializableFinder of = ByType('Text');
+    final SerializableFinder matching = ByValueKey('hello');
+
+    final Descendant a = Descendant(
+      of: of,
+      matching: matching,
+      matchRoot: true,
+    );
+    expect(a.serialize(), <String, String>{
+      'finderType': 'Descendant',
+      'of_finderType': 'ByType',
+      'of_type': 'Text',
+      'matching_finderType': 'ByValueKey',
+      'matching_keyValueString': 'hello',
+      'matching_keyValueType': 'String',
+      'matchRoot': 'true'
+    });
+  });
+
+  test('Descendant finder deserialize', () {
+    final Map<String, String> serialized = <String, String>{
+      'finderType': 'Descendant',
+      'of_finderType': 'ByType',
+      'of_type': 'Text',
+      'matching_finderType': 'ByValueKey',
+      'matching_keyValueString': 'hello',
+      'matching_keyValueType': 'String',
+      'matchRoot': 'true'
+    };
+
+    final Descendant a = Descendant.deserialize(serialized);
+    expect(a.of, isA<ByType>());
+    expect(a.matching, isA<ByValueKey>());
+    expect(a.matchRoot, isTrue);
+  });
+}