Flutter Driver - Create widget finders from serialized finders extensions (#67456)

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

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/cupertino.dart';
+
+import 'find.dart';
+
+/// A factory which creates [Finder]s from [SerializableFinder]s.
+mixin CreateFinderFactory {
+  /// Creates the flutter widget finder from [SerializableFinder].
+  Finder createFinder(SerializableFinder finder) {
+    switch (finder.finderType) {
+      case 'ByText':
+        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:
+        return null;
+    }
+  }
+
+  Finder _createByTextFinder(ByText arguments) {
+    return find.text(arguments.text);
+  }
+
+  Finder _createByTooltipMessageFinder(ByTooltipMessage arguments) {
+    return find.byElementPredicate((Element element) {
+      final Widget widget = element.widget;
+      if (widget is Tooltip) {
+        return widget.message == arguments.text;
+      }
+      return false;
+    }, description: 'widget with text tooltip "${arguments.text}"');
+  }
+
+  Finder _createBySemanticsLabelFinder(BySemanticsLabel arguments) {
+    return find.byElementPredicate((Element element) {
+      if (element is! RenderObjectElement) {
+        return false;
+      }
+      final String semanticsLabel = element.renderObject?.debugSemantics?.label;
+      if (semanticsLabel == null) {
+        return false;
+      }
+      final Pattern label = arguments.label;
+      return label is RegExp
+          ? label.hasMatch(semanticsLabel)
+          : label == semanticsLabel;
+    }, description: 'widget with semantic label "${arguments.label}"');
+  }
+
+  Finder _createByValueKeyFinder(ByValueKey arguments) {
+    switch (arguments.keyValueType) {
+      case 'int':
+        return find.byKey(ValueKey<int>(arguments.keyValue as int));
+      case 'String':
+        return find.byKey(ValueKey<String>(arguments.keyValue as String));
+      default:
+        throw 'Unsupported ByValueKey type: ${arguments.keyValueType}';
+    }
+  }
+
+  Finder _createByTypeFinder(ByType arguments) {
+    return find.byElementPredicate((Element element) {
+      return element.widget.runtimeType.toString() == arguments.type;
+    }, description: 'widget with runtimeType "${arguments.type}"');
+  }
+
+  Finder _createPageBackFinder() {
+    return find.byElementPredicate((Element element) {
+      final Widget widget = element.widget;
+      if (widget is Tooltip) {
+        return widget.message == 'Back';
+      }
+      if (widget is CupertinoNavigationBarBackButton) {
+        return true;
+      }
+      return false;
+    }, description: 'Material or Cupertino back button');
+  }
+
+  Finder _createAncestorFinder(Ancestor arguments) {
+    final Finder finder = find.ancestor(
+      of: createFinder(arguments.of),
+      matching: createFinder(arguments.matching),
+      matchRoot: arguments.matchRoot,
+    );
+    return arguments.firstMatchOnly ? finder.first : finder;
+  }
+
+  Finder _createDescendantFinder(Descendant arguments) {
+    final Finder finder = find.descendant(
+      of: createFinder(arguments.of),
+      matching: createFinder(arguments.matching),
+      matchRoot: arguments.matchRoot,
+    );
+    return arguments.firstMatchOnly ? finder.first : finder;
+  }
+}

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

@@ -24,7 +24,7 @@ mixin DeserializeFinderFactory {
       case 'Descendant': return Descendant.deserialize(json, this);
       case 'Ancestor': return Ancestor.deserialize(json, this);
     }
-    throw DriverError('Unsupported search specification type $finderType');
+    return null;
   }
 }
 

packages/flutter_driver/test/src/real_tests/stubs/stub_finder.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_driver/flutter_driver.dart';
+
+class StubFinder extends SerializableFinder {
+  StubFinder(this.keyString);
+
+  final String keyString;
+
+  @override
+  String get finderType => 'Stub';
+
+  @override
+  Map<String, String> serialize() {
+    return super.serialize()..addAll(<String, String>{'keyString': keyString});
+  }
+}

packages/flutter_driver/test/src/real_tests/stubs/stub_finder_extension.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/src/widgets/framework.dart';
+import 'package:flutter_driver/driver_extension.dart';
+import 'package:flutter_driver/src/common/create_finder_factory.dart';
+import 'package:flutter_test/src/finders.dart';
+import 'package:flutter_driver/src/common/find.dart';
+
+import 'stub_finder.dart';
+
+class StubFinderExtension extends FinderExtension {
+  @override
+  Finder createFinder(
+    SerializableFinder finder,
+    CreateFinderFactory finderFactory,
+  ) {
+    return find.byWidgetPredicate((Widget widget) {
+      final Key key = widget.key;
+      if (key is! ValueKey<String>) {
+        return false;
+      }
+      return (key as ValueKey<String>).value == (finder as StubFinder).keyString;
+    });
+  }
+
+  @override
+  SerializableFinder deserialize(
+    Map<String, String> params,
+    DeserializeFinderFactory finderFactory,
+  ) {
+    return StubFinder(params['keyString']);
+  }
+
+  @override
+  String get finderType => 'Stub';
+}