Add finders for enableFlutterDriverExtension (#64308)

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

@@ -33,11 +33,11 @@ class GetDiagnosticsTree extends CommandWithTarget {
        super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  GetDiagnosticsTree.deserialize(Map<String, String> json)
+  GetDiagnosticsTree.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
       : subtreeDepth = int.parse(json['subtreeDepth']),
         includeProperties = json['includeProperties'] == 'true',
         diagnosticsType = _diagnosticsTypeIndex.lookupBySimpleName(json['diagnosticsType']),
-        super.deserialize(json);
+        super.deserialize(json, finderFactory);
 
   /// How many levels of children to include in the JSON result.
   ///

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

@@ -9,6 +9,25 @@ import 'package:meta/meta.dart';
 import 'error.dart';
 import 'message.dart';
 
+/// A factory for deserializing [Finder]s.
+mixin DeserializeFinderFactory {
+  /// Deserializes the finder from JSON generated by [SerializableFinder.serialize].
+  SerializableFinder deserializeFinder(Map<String, String> json) {
+    final String finderType = json['finderType'];
+    switch (finderType) {
+      case 'ByType': return ByType.deserialize(json);
+      case 'ByValueKey': return ByValueKey.deserialize(json);
+      case 'ByTooltipMessage': return ByTooltipMessage.deserialize(json);
+      case 'BySemanticsLabel': return BySemanticsLabel.deserialize(json);
+      case 'ByText': return ByText.deserialize(json);
+      case 'PageBack': return const PageBack();
+      case 'Descendant': return Descendant.deserialize(json, this);
+      case 'Ancestor': return Ancestor.deserialize(json, this);
+    }
+    throw DriverError('Unsupported search specification type $finderType');
+  }
+}
+
 const List<Type> _supportedKeyValueTypes = <Type>[String, int];
 
 DriverError _createInvalidKeyValueTypeError(String invalidType) {
@@ -28,8 +47,8 @@ abstract class CommandWithTarget extends Command {
   }
 
   /// Deserializes this command from the value generated by [serialize].
-  CommandWithTarget.deserialize(Map<String, String> json)
+  CommandWithTarget.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
-    : finder = SerializableFinder.deserialize(json),
+    : finder = finderFactory.deserializeFinder(json),
       super.deserialize(json);
 
   /// Locates the object or objects targeted by this command.
@@ -58,7 +77,7 @@ class WaitFor extends CommandWithTarget {
     : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  WaitFor.deserialize(Map<String, String> json) : super.deserialize(json);
+  WaitFor.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory) : super.deserialize(json, finderFactory);
 
   @override
   String get kind => 'waitFor';
@@ -88,7 +107,7 @@ class WaitForAbsent extends CommandWithTarget {
     : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  WaitForAbsent.deserialize(Map<String, String> json) : super.deserialize(json);
+  WaitForAbsent.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory) : super.deserialize(json, finderFactory);
 
   @override
   String get kind => 'waitForAbsent';
@@ -126,22 +145,6 @@ abstract class SerializableFinder {
   Map<String, String> serialize() => <String, String>{
     'finderType': finderType,
   };
-
-  /// Deserializes a finder from JSON generated by [serialize].
-  static SerializableFinder deserialize(Map<String, String> json) {
-    final String finderType = json['finderType'];
-    switch (finderType) {
-      case 'ByType': return ByType.deserialize(json);
-      case 'ByValueKey': return ByValueKey.deserialize(json);
-      case 'ByTooltipMessage': return ByTooltipMessage.deserialize(json);
-      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');
-  }
 }
 
 /// A Flutter Driver finder that finds widgets by tooltip text.
@@ -349,14 +352,14 @@ class Descendant extends SerializableFinder {
   }
 
   /// Deserializes the finder from JSON generated by [serialize].
-  static Descendant deserialize(Map<String, String> json) {
+  static Descendant deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory) {
     final Map<String, String> jsonOfMatcher =
         Map<String, String>.from(jsonDecode(json['of']) as Map<String, dynamic>);
     final Map<String, String> jsonMatchingMatcher =
         Map<String, String>.from(jsonDecode(json['matching']) as Map<String, dynamic>);
     return Descendant(
-      of: SerializableFinder.deserialize(jsonOfMatcher),
+      of: finderFactory.deserializeFinder(jsonOfMatcher),
-      matching: SerializableFinder.deserialize(jsonMatchingMatcher),
+      matching: finderFactory.deserializeFinder(jsonMatchingMatcher),
       matchRoot: json['matchRoot'] == 'true',
       firstMatchOnly: json['firstMatchOnly'] == 'true',
     );
@@ -404,14 +407,14 @@ class Ancestor extends SerializableFinder {
   }
 
   /// Deserializes the finder from JSON generated by [serialize].
-  static Ancestor deserialize(Map<String, String> json) {
+  static Ancestor deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory) {
     final Map<String, String> jsonOfMatcher =
         Map<String, String>.from(jsonDecode(json['of']) as Map<String, dynamic>);
     final Map<String, String> jsonMatchingMatcher =
         Map<String, String>.from(jsonDecode(json['matching']) as Map<String, dynamic>);
     return Ancestor(
-      of: SerializableFinder.deserialize(jsonOfMatcher),
+      of: finderFactory.deserializeFinder(jsonOfMatcher),
-      matching: SerializableFinder.deserialize(jsonMatchingMatcher),
+      matching: finderFactory.deserializeFinder(jsonMatchingMatcher),
       matchRoot: json['matchRoot'] == 'true',
       firstMatchOnly: json['firstMatchOnly'] == 'true',
     );
@@ -436,8 +439,8 @@ class GetSemanticsId extends CommandWithTarget {
   GetSemanticsId(SerializableFinder finder, {Duration timeout}) : super(finder, timeout: timeout);
 
   /// Creates a command from a JSON map.
-  GetSemanticsId.deserialize(Map<String, String> json)
+  GetSemanticsId.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
-    : super.deserialize(json);
+    : super.deserialize(json, finderFactory);
 
   @override
   String get kind => 'get_semantics_id';

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

@@ -36,9 +36,9 @@ class GetOffset extends CommandWithTarget {
   GetOffset(SerializableFinder finder,  this.offsetType, { Duration timeout }) : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  GetOffset.deserialize(Map<String, String> json)
+  GetOffset.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
       : offsetType = _offsetTypeIndex.lookupBySimpleName(json['offsetType']),
-        super.deserialize(json);
+        super.deserialize(json, finderFactory);
 
   @override
   Map<String, String> serialize() => super.serialize()..addAll(<String, String>{

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

@@ -11,7 +11,7 @@ class Tap extends CommandWithTarget {
   Tap(SerializableFinder finder, { Duration timeout }) : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  Tap.deserialize(Map<String, String> json) : super.deserialize(json);
+  Tap.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory) : super.deserialize(json, finderFactory);
 
   @override
   String get kind => 'tap';
@@ -46,12 +46,12 @@ class Scroll extends CommandWithTarget {
   }) : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  Scroll.deserialize(Map<String, String> json)
+  Scroll.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
     : dx = double.parse(json['dx']),
       dy = double.parse(json['dy']),
       duration = Duration(microseconds: int.parse(json['duration'])),
       frequency = int.parse(json['frequency']),
-      super.deserialize(json);
+      super.deserialize(json, finderFactory);
 
   /// Delta X offset per move event.
   final double dx;
@@ -99,9 +99,9 @@ class ScrollIntoView extends CommandWithTarget {
   ScrollIntoView(SerializableFinder finder, { this.alignment = 0.0, Duration timeout }) : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  ScrollIntoView.deserialize(Map<String, String> json)
+  ScrollIntoView.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
     : alignment = double.parse(json['alignment']),
-      super.deserialize(json);
+      super.deserialize(json, finderFactory);
 
   /// How the widget should be aligned.
   ///

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

@@ -11,7 +11,7 @@ class GetText extends CommandWithTarget {
   GetText(SerializableFinder finder, { Duration timeout }) : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
-  GetText.deserialize(Map<String, String> json) : super.deserialize(json);
+  GetText.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory) : super.deserialize(json, finderFactory);
 
   @override
   String get kind => 'get_text';

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

@@ -43,15 +43,16 @@ const String _extensionMethod = 'ext.flutter.$_extensionMethodName';
 typedef DataHandler = Future<String> Function(String message);
 
 class _DriverBinding extends BindingBase with SchedulerBinding, ServicesBinding, GestureBinding, PaintingBinding, SemanticsBinding, RendererBinding, WidgetsBinding {
-  _DriverBinding(this._handler, this._silenceErrors);
+  _DriverBinding(this._handler, this._silenceErrors, this.finders);
 
   final DataHandler _handler;
   final bool _silenceErrors;
+  final List<FinderExtension> finders;
 
   @override
   void initServiceExtensions() {
     super.initServiceExtensions();
-    final FlutterDriverExtension extension = FlutterDriverExtension(_handler, _silenceErrors);
+    final FlutterDriverExtension extension = FlutterDriverExtension(_handler, _silenceErrors, finders);
     registerServiceExtension(
       name: _extensionMethodName,
       callback: extension.call,
@@ -86,9 +87,59 @@ class _DriverBinding extends BindingBase with SchedulerBinding, ServicesBinding,
 /// for tests where exceptions are expected. Defaults to false. Any errors
 /// will still be returned in the `response` field of the result JSON along
 /// with an `isError` boolean.
-void enableFlutterDriverExtension({ DataHandler handler, bool silenceErrors = false }) {
+///
+/// The `finders` parameter are used to add custom finders, as in the following example.
+///
+/// ```dart main
+/// void main() {
+///   enableFlutterDriverExtension(finders: <FinderExtension>[ SomeFinderExtension() ]);
+///
+///   app.main();
+/// }
+/// ```
+///
+/// ```dart
+/// class Some extends SerializableFinder {
+///   const Some(this.title);
+///
+///   final String title;
+///
+///   @override
+///   String get finderType => 'Some';
+///
+///   @override
+///   Map<String, String> serialize() => super.serialize()..addAll(<String, String>{
+///     'title': title,
+///   });
+/// }
+/// ```
+///
+/// ```dart
+/// class SomeFinderExtension extends FinderExtension {
+///
+///  String get finderType => 'Some';
+///
+///  SerializableFinder deserialize(Map<String, String> params, DeserializeFinderFactory finderFactory) {
+///    return Some(json['title']);
+///  }
+///
+///  Finder createFinder(SerializableFinder finder) {
+///    Some someFinder = finder as Some;
+///
+///    return find.byElementPredicate((Element element) {
+///      final Widget widget = element.widget;
+///      if (element.widget is SomeWidget) {
+///        return element.widget.title == someFinder.title;
+///      }
+///      return false;
+///    });
+///  }
+/// }
+/// ```
+///
+void enableFlutterDriverExtension({ DataHandler handler, bool silenceErrors = false, List<FinderExtension> finders}) {
   assert(WidgetsBinding.instance == null);
-  _DriverBinding(handler, silenceErrors);
+  _DriverBinding(handler, silenceErrors, finders ?? <FinderExtension>[]);
   assert(WidgetsBinding.instance is _DriverBinding);
 }
 
@@ -98,9 +149,19 @@ typedef CommandHandlerCallback = Future<Result> Function(Command c);
 /// Signature for functions that deserialize a JSON map to a command object.
 typedef CommandDeserializerCallback = Command Function(Map<String, String> params);
 
-/// Signature for functions that run the given finder and return the [Element]
+/// Used to expand the new Finder
-/// found, if any, or null otherwise.
+abstract class FinderExtension {
-typedef FinderConstructor = Finder Function(SerializableFinder finder);
+
+  /// Identifies the type of finder to be used by the driver extension.
+  String get finderType;
+
+  /// Deserializes the finder from JSON generated by [SerializableFinder.serialize].
+  SerializableFinder deserialize(Map<String, String> params, DeserializeFinderFactory finderFactory);
+
+  /// Signature for functions that run the given finder and return the [Element]
+  /// found, if any, or null otherwise.
+  Finder createFinder(SerializableFinder finder);
+}
 
 /// The class that manages communication between a Flutter Driver test and the
 /// application being remote-controlled, on the application side.
@@ -108,9 +169,9 @@ typedef FinderConstructor = Finder Function(SerializableFinder finder);
 /// This is not normally used directly. It is instantiated automatically when
 /// calling [enableFlutterDriverExtension].
 @visibleForTesting
-class FlutterDriverExtension {
+class FlutterDriverExtension with DeserializeFinderFactory {
   /// Creates an object to manage a Flutter Driver connection.
-  FlutterDriverExtension(this._requestDataHandler, this._silenceErrors) {
+  FlutterDriverExtension(this._requestDataHandler, this._silenceErrors, List<FinderExtension> finders) {
     _testTextInput.register();
 
     _commandHandlers.addAll(<String, CommandHandlerCallback>{
@@ -142,35 +203,28 @@ class FlutterDriverExtension {
       'get_layer_tree': (Map<String, String> params) => GetLayerTree.deserialize(params),
       'get_render_tree': (Map<String, String> params) => GetRenderTree.deserialize(params),
       'enter_text': (Map<String, String> params) => EnterText.deserialize(params),
-      'get_text': (Map<String, String> params) => GetText.deserialize(params),
+      'get_text': (Map<String, String> params) => GetText.deserialize(params, this),
       'request_data': (Map<String, String> params) => RequestData.deserialize(params),
-      'scroll': (Map<String, String> params) => Scroll.deserialize(params),
+      'scroll': (Map<String, String> params) => Scroll.deserialize(params, this),
-      'scrollIntoView': (Map<String, String> params) => ScrollIntoView.deserialize(params),
+      'scrollIntoView': (Map<String, String> params) => ScrollIntoView.deserialize(params, this),
       'set_frame_sync': (Map<String, String> params) => SetFrameSync.deserialize(params),
       'set_semantics': (Map<String, String> params) => SetSemantics.deserialize(params),
       'set_text_entry_emulation': (Map<String, String> params) => SetTextEntryEmulation.deserialize(params),
-      'tap': (Map<String, String> params) => Tap.deserialize(params),
+      'tap': (Map<String, String> params) => Tap.deserialize(params, this),
-      'waitFor': (Map<String, String> params) => WaitFor.deserialize(params),
+      'waitFor': (Map<String, String> params) => WaitFor.deserialize(params, this),
-      'waitForAbsent': (Map<String, String> params) => WaitForAbsent.deserialize(params),
+      'waitForAbsent': (Map<String, String> params) => WaitForAbsent.deserialize(params, this),
       'waitForCondition': (Map<String, String> params) => WaitForCondition.deserialize(params),
       'waitUntilNoTransientCallbacks': (Map<String, String> params) => WaitUntilNoTransientCallbacks.deserialize(params),
       'waitUntilNoPendingFrame': (Map<String, String> params) => WaitUntilNoPendingFrame.deserialize(params),
       'waitUntilFirstFrameRasterized': (Map<String, String> params) => WaitUntilFirstFrameRasterized.deserialize(params),
-      'get_semantics_id': (Map<String, String> params) => GetSemanticsId.deserialize(params),
+      'get_semantics_id': (Map<String, String> params) => GetSemanticsId.deserialize(params, this),
-      'get_offset': (Map<String, String> params) => GetOffset.deserialize(params),
+      'get_offset': (Map<String, String> params) => GetOffset.deserialize(params, this),
-      'get_diagnostics_tree': (Map<String, String> params) => GetDiagnosticsTree.deserialize(params),
+      'get_diagnostics_tree': (Map<String, String> params) => GetDiagnosticsTree.deserialize(params, this),
     });
 
-    _finders.addAll(<String, FinderConstructor>{
+    for(final FinderExtension finder in finders) {
-      'ByText': (SerializableFinder finder) => _createByTextFinder(finder as ByText),
+      _finderExtensions[finder.finderType] = finder;
-      'ByTooltipMessage': (SerializableFinder finder) => _createByTooltipMessageFinder(finder as ByTooltipMessage),
+    }
-      'BySemanticsLabel': (SerializableFinder finder) => _createBySemanticsLabelFinder(finder as BySemanticsLabel),
-      'ByValueKey': (SerializableFinder finder) => _createByValueKeyFinder(finder as ByValueKey),
-      'ByType': (SerializableFinder finder) => _createByTypeFinder(finder as ByType),
-      'PageBack': (SerializableFinder finder) => _createPageBackFinder(),
-      'Ancestor': (SerializableFinder finder) => _createAncestorFinder(finder as Ancestor),
-      'Descendant': (SerializableFinder finder) => _createDescendantFinder(finder as Descendant),
-    });
   }
 
   final TestTextInput _testTextInput = TestTextInput();
@@ -185,7 +239,7 @@ class FlutterDriverExtension {
   final WidgetController _prober = LiveWidgetController(WidgetsBinding.instance);
   final Map<String, CommandHandlerCallback> _commandHandlers = <String, CommandHandlerCallback>{};
   final Map<String, CommandDeserializerCallback> _commandDeserializers = <String, CommandDeserializerCallback>{};
-  final Map<String, FinderConstructor> _finders = <String, FinderConstructor>{};
+  final Map<String, FinderExtension> _finderExtensions = <String, FinderExtension>{};
 
   /// With [_frameSync] enabled, Flutter Driver will wait to perform an action
   /// until there are no pending frames in the app under test.
@@ -372,12 +426,30 @@ class FlutterDriverExtension {
   }
 
   Finder _createFinder(SerializableFinder finder) {
-    final FinderConstructor constructor = _finders[finder.finderType];
+    switch (finder.finderType) {
-
+      case 'ByText':
-    if (constructor == null)
+        return _createByTextFinder(finder as ByText);
+      case 'ByTooltipMessage':
+        return _createByTooltipMessageFinder(finder as ByTooltipMessage);
+      case 'BySemanticsLabel':
+        return _createBySemanticsLabelFinder(finder as BySemanticsLabel);
+      case 'ByValueKey':
+        return _createByValueKeyFinder(finder as ByValueKey);
+      case 'ByType':
+        return _createByTypeFinder(finder as ByType);
+      case 'PageBack':
+        return _createPageBackFinder();
+      case 'Ancestor':
+        return _createAncestorFinder(finder as Ancestor);
+      case 'Descendant':
+        return _createDescendantFinder(finder as Descendant);
+      default:
+        if (_finderExtensions.containsKey(finder.finderType)) {
+          return _finderExtensions[finder.finderType].createFinder(finder);
+        } else {
           throw 'Unsupported finder type: ${finder.finderType}';
-
+        }
-    return constructor(finder);
+    }
   }
 
   Future<TapResult> _tap(Command command) async {

packages/flutter_driver/test/src/real_tests/extension_test.dart

@@ -37,7 +37,7 @@ void main() {
 
     setUp(() {
       result = null;
-      extension = FlutterDriverExtension((String message) async { log.add(message); return (messageId += 1).toString(); }, false);
+      extension = FlutterDriverExtension((String message) async { log.add(message); return (messageId += 1).toString(); }, false, <FinderExtension>[]);
     });
 
     testWidgets('returns immediately when transient callback queue is empty', (WidgetTester tester) async {
@@ -98,7 +98,7 @@ void main() {
 
     setUp(() {
       result = null;
-      extension = FlutterDriverExtension((String message) async { log.add(message); return (messageId += 1).toString(); }, false);
+      extension = FlutterDriverExtension((String message) async { log.add(message); return (messageId += 1).toString(); }, false, <FinderExtension>[]);
     });
 
     testWidgets('waiting for NoTransientCallbacks returns immediately when transient callback queue is empty', (WidgetTester tester) async {
@@ -464,7 +464,7 @@ void main() {
   group('getSemanticsId', () {
     FlutterDriverExtension extension;
     setUp(() {
-      extension = FlutterDriverExtension((String arg) async => '', true);
+      extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
     });
 
     testWidgets('works when semantics are enabled', (WidgetTester tester) async {
@@ -513,7 +513,7 @@ void main() {
   });
 
   testWidgets('getOffset', (WidgetTester tester) async {
-    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
     Future<Offset> getOffset(OffsetType offset) async {
       final Map<String, String> arguments = GetOffset(ByValueKey(1), offset).serialize();
@@ -545,7 +545,7 @@ void main() {
 
   testWidgets('getText', (WidgetTester tester) async {
     await silenceDriverLogger(() async {
-      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
       Future<String> getTextInternal(SerializableFinder search) async {
         final Map<String, String> arguments = GetText(search, timeout: const Duration(seconds: 1)).serialize();
@@ -615,7 +615,7 @@ void main() {
 
   testWidgets('descendant finder', (WidgetTester tester) async {
     await silenceDriverLogger(() async {
-      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
       Future<String> getDescendantText({ String of, bool matchRoot = false}) async {
         final Map<String, String> arguments = GetText(Descendant(
@@ -660,7 +660,7 @@ void main() {
 
   testWidgets('descendant finder firstMatchOnly', (WidgetTester tester) async {
     await silenceDriverLogger(() async {
-      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
       Future<String> getDescendantText() async {
         final Map<String, String> arguments = GetText(Descendant(
@@ -694,7 +694,7 @@ void main() {
 
   testWidgets('ancestor finder', (WidgetTester tester) async {
     await silenceDriverLogger(() async {
-      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
       Future<Offset> getAncestorTopLeft({ String of, String matching, bool matchRoot = false}) async {
         final Map<String, String> arguments = GetOffset(Ancestor(
@@ -764,7 +764,7 @@ void main() {
 
   testWidgets('ancestor finder firstMatchOnly', (WidgetTester tester) async {
     await silenceDriverLogger(() async {
-      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+      final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
       Future<Offset> getAncestorTopLeft() async {
         final Map<String, String> arguments = GetOffset(Ancestor(
@@ -812,7 +812,7 @@ void main() {
   });
 
   testWidgets('GetDiagnosticsTree', (WidgetTester tester) async {
-    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
 
     Future<Map<String, Object>> getDiagnosticsTree(DiagnosticsType type, SerializableFinder finder, { int depth = 0, bool properties = true }) async {
       final Map<String, String> arguments = GetDiagnosticsTree(finder, type, subtreeDepth: depth, includeProperties: properties).serialize();
@@ -882,7 +882,7 @@ void main() {
     Map<String, dynamic> result;
 
     setUp(() {
-      extension = FlutterDriverExtension((String arg) async => '', true);
+      extension = FlutterDriverExtension((String arg) async => '', true, <FinderExtension>[]);
       result = null;
     });
 

packages/flutter_driver/test/src/real_tests/find_test.dart

@@ -2,11 +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_driver/flutter_driver.dart';
 import 'package:flutter_driver/src/common/find.dart';
+import 'package:mockito/mockito.dart';
 
 import '../../common.dart';
 
 void main() {
+  MockDeserialize mockDeserialize;
+
   test('Ancestor finder serialize', () {
     const SerializableFinder of = ByType('Text');
     final SerializableFinder matching = ByValueKey('hello');
@@ -35,7 +39,7 @@ void main() {
       'firstMatchOnly': 'true',
     };
 
-    final Ancestor a = Ancestor.deserialize(serialized);
+    final Ancestor a = Ancestor.deserialize(serialized, mockDeserialize);
     expect(a.of, isA<ByType>());
     expect(a.matching, isA<ByValueKey>());
     expect(a.matchRoot, isTrue);
@@ -70,10 +74,12 @@ void main() {
       'firstMatchOnly': 'true',
     };
 
-    final Descendant a = Descendant.deserialize(serialized);
+    final Descendant a = Descendant.deserialize(serialized, mockDeserialize);
     expect(a.of, isA<ByType>());
     expect(a.matching, isA<ByValueKey>());
     expect(a.matchRoot, isTrue);
     expect(a.firstMatchOnly, isTrue);
   });
 }
+
+class MockDeserialize with Mock, DeserializeFinderFactory { }