[pigeon] Add local-only Java integration tests (#2854)

* Move generated code to a new shared bundle.

* Consolidate the example app code

* Replace stale TODOs with explanatory comments

* Move integration tests

* Add Java implementation

* Add test script commands

* Autoformat

packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java

@@ -5,16 +5,39 @@
 package com.example.alternate_language_test_plugin;
 
 import androidx.annotation.NonNull;
+import com.example.alternate_language_test_plugin.AllDatatypes.Everything;
+import com.example.alternate_language_test_plugin.AllDatatypes.HostEverything;
+import com.example.alternate_language_test_plugin.AllVoid.AllVoidHostApi;
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
 
-/**
- * This plugin is currently a no-op since only unit tests have been set up. In the future, this will
- * register Pigeon APIs used in integration tests.
- */
-public class AlternateLanguageTestPlugin implements FlutterPlugin {
+/** This plugin handles the native side of the integration tests in example/integration_test/. */
+public class AlternateLanguageTestPlugin implements FlutterPlugin, AllVoidHostApi, HostEverything {
   @Override
-  public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {}
+  public void onAttachedToEngine(@NonNull FlutterPluginBinding binding) {
+    AllVoidHostApi.setup(binding.getBinaryMessenger(), this);
+    HostEverything.setup(binding.getBinaryMessenger(), this);
+  }
 
   @Override
   public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {}
+
+  // AllVoidHostApi
+
+  @Override
+  public void doit() {
+    // No-op.
+  }
+
+  // HostEverything
+
+  @Override
+  public @NonNull Everything giveMeEverything() {
+    // Currently unused in integration tests, so just return an empty object.
+    return new Everything();
+  }
+
+  @Override
+  public @NonNull Everything echo(@NonNull Everything everything) {
+    return everything;
+  }
 }

packages/pigeon/platform_tests/alternate_language_test_plugin/example/integration_test/test.dart

@@ -0,0 +1,7 @@
+// Copyright 2013 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:shared_test_plugin_code/integration_tests.dart';
+
+void main() => runPigeonIntegrationTests();

packages/pigeon/platform_tests/alternate_language_test_plugin/example/lib/main.dart

@@ -2,51 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// ignore_for_file: public_member_api_docs
-
-import 'package:alternate_language_test_plugin/alternate_language_test_plugin.dart';
 import 'package:flutter/material.dart';
+import 'package:shared_test_plugin_code/example_app.dart';
 
 void main() {
-  runApp(const MyApp());
-}
-
-class MyApp extends StatefulWidget {
-  const MyApp({super.key});
-
-  @override
-  State<MyApp> createState() => _MyAppState();
-}
-
-class _MyAppState extends State<MyApp> {
-  // ignore: unused_field
-  final AlternateLanguageTestPlugin _alternateLanguageTestPlugin =
-      AlternateLanguageTestPlugin();
-
-  @override
-  void initState() {
-    super.initState();
-    initPlatformState();
-  }
-
-  Future<void> initPlatformState() async {
-    // TODO(tarrinneal): Call TestPlugin methods here for manual integration
-    // testing, once they exist. See
-    // https://github.com/flutter/flutter/issues/111505
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return MaterialApp(
-      home: Scaffold(
-        appBar: AppBar(
-          title: const Text('Pigeon integration tests'),
-        ),
-        body: const Center(
-          child: Text(
-              'TODO, see https://github.com/flutter/flutter/issues/111505'),
-        ),
-      ),
-    );
-  }
+  runApp(const ExampleApp());
 }

packages/pigeon/platform_tests/alternate_language_test_plugin/example/pubspec.yaml

@@ -10,10 +10,14 @@ dependencies:
     path: ../
   flutter:
     sdk: flutter
+  shared_test_plugin_code:
+    path: ../../shared_test_plugin_code
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  integration_test:
+    sdk: flutter
 
 flutter:
   uses-material-design: true

packages/pigeon/platform_tests/alternate_language_test_plugin/lib/.gitignore

@@ -1,9 +0,0 @@
-# TODO(stuartmorgan): Remove this, so that review will show the effects of
-# changes on generated files. This will need a way to avoid unnecessary churn,
-# such as a flag to suppress version stamp generation.
-*.gen.dart
-# TODO(stuartmorgan): Add exceptions for specific files that are used in
-# integration tests, as they will need to be checked in to avoid analysis
-# failures. The exclusion of other files is to prevent having multiple
-# copies of all of the Dart output until more tests are restructured to
-# minimize duplication.

packages/pigeon/platform_tests/alternate_language_test_plugin/lib/alternate_language_test_plugin.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(tarrinneal): Add integration tests.
-
-/// A host plugin for Pigeon tests.
-class AlternateLanguageTestPlugin {}
+// There is intentionally no code here; tests use generated Pigeon APIs
+// directly, as wrapping them in a plugin would just add maintenance burden
+// when changing tests.

packages/pigeon/platform_tests/shared_test_plugin_code/.gitignore

@@ -0,0 +1,30 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+# Libraries should not include pubspec.lock, per https://dart.dev/guides/libraries/private-files#pubspeclock.
+/pubspec.lock
+**/doc/api/
+.dart_tool/
+.packages
+build/

packages/pigeon/platform_tests/shared_test_plugin_code/.metadata

@@ -0,0 +1,10 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: c940f318226901f7ba9ccb68f216756ced2fe3c7
+  channel: main
+
+project_type: package

packages/pigeon/platform_tests/shared_test_plugin_code/README.md

@@ -0,0 +1,7 @@
+This package contains the shared code (generated Pigeon output, example app,
+integration tests) for `test_plugin` and `alternate_language_shared_plugin`.
+
+Since those two plugin projects are intended to be identical, and only exist
+as separate projects because of the Java/Kotlin and Obj-C/Swift overlap that
+prevents combining them, almost all Dart code should be in this package rather
+than in the plugins themselves.

packages/pigeon/platform_tests/shared_test_plugin_code/lib/example_app.dart

@@ -0,0 +1,66 @@
+// Copyright 2013 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/material.dart';
+
+import 'generated.dart';
+
+void main() {
+  runApp(const ExampleApp());
+}
+
+/// A trivial example that validates that Pigeon is able to successfully call
+/// into native code.
+///
+/// Actual testing is all done in the integration tests, which run in the
+/// context of the example app but don't actually rely on this class.
+class ExampleApp extends StatefulWidget {
+  /// Creates a new example app.
+  const ExampleApp({super.key});
+
+  @override
+  State<ExampleApp> createState() => _ExampleAppState();
+}
+
+class _ExampleAppState extends State<ExampleApp> {
+  // This just uses a single API since it's intended only a minimal check
+  // that the basics are wired up correctly.
+  late final AllVoidHostApi api;
+  String status = 'Calling...';
+
+  @override
+  void initState() {
+    super.initState();
+    initPlatformState();
+  }
+
+  Future<void> initPlatformState() async {
+    api = AllVoidHostApi();
+    try {
+      await api.doit();
+    } catch (e) {
+      setState(() {
+        status = 'Failed: $e';
+      });
+      return;
+    }
+    setState(() {
+      status = 'Success!';
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Pigeon integration tests'),
+        ),
+        body: Center(
+          child: Text(status),
+        ),
+      ),
+    );
+  }
+}

packages/pigeon/platform_tests/shared_test_plugin_code/lib/generated.dart

@@ -0,0 +1,6 @@
+// Copyright 2013 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.
+
+export 'src/generated/all_datatypes.gen.dart';
+export 'src/generated/all_void.gen.dart';

packages/pigeon/platform_tests/shared_test_plugin_code/lib/integration_tests.dart

@@ -0,0 +1,80 @@
+// Copyright 2013 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.
+
+// TODO(a14n): remove this import once Flutter 3.1 or later reaches stable (including flutter/flutter#104231)
+// ignore: unnecessary_import
+import 'dart:typed_data';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+
+import 'generated.dart';
+
+/// Sets up and runs the integration tests.
+void runPigeonIntegrationTests() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  group('Host API tests', () {
+    testWidgets('voidCallVoidReturn', (WidgetTester _) async {
+      final AllVoidHostApi api = AllVoidHostApi();
+
+      expect(api.doit(), completes);
+    });
+
+    testWidgets('allDataTypesEcho', (WidgetTester _) async {
+      final HostEverything api = HostEverything();
+
+      final Everything sentObject = Everything(
+        aBool: true,
+        anInt: 42,
+        aDouble: 3.14159,
+        aString: 'Hello host!',
+        aByteArray: Uint8List.fromList(<int>[1, 2, 3]),
+        a4ByteArray: Int32List.fromList(<int>[4, 5, 6]),
+        a8ByteArray: Int64List.fromList(<int>[7, 8, 9]),
+        aFloatArray: Float64List.fromList(<double>[2.71828, 3.14159]),
+        aList: <Object?>['Thing 1', 2],
+        aMap: <Object?, Object?>{'a': 1, 'b': 2.0},
+        nestedList: <List<bool>>[
+          <bool>[true, false],
+          <bool>[false, true]
+        ],
+      );
+
+      final Everything echoObject = await api.echo(sentObject);
+      expect(echoObject.aBool, sentObject.aBool);
+      expect(echoObject.anInt, sentObject.anInt);
+      expect(echoObject.aDouble, sentObject.aDouble);
+      expect(echoObject.aString, sentObject.aString);
+      // TODO(stuartmorgan): Enable these once they work for all generators;
+      // currently at least Swift is broken.
+      // See https://github.com/flutter/flutter/issues/115906
+      //expect(echoObject.aByteArray, sentObject.aByteArray);
+      //expect(echoObject.a4ByteArray, sentObject.a4ByteArray);
+      //expect(echoObject.a8ByteArray, sentObject.a8ByteArray);
+      //expect(echoObject.aFloatArray, sentObject.aFloatArray);
+      expect(listEquals(echoObject.aList, sentObject.aList), true);
+      expect(mapEquals(echoObject.aMap, sentObject.aMap), true);
+      expect(echoObject.nestedList?.length, sentObject.nestedList?.length);
+      // TODO(stuartmorgan): Enable this once the Dart types are fixed; see
+      // https://github.com/flutter/flutter/issues/116117
+      //for (int i = 0; i < echoObject.nestedList!.length; i++) {
+      //  expect(listEquals(echoObject.nestedList![i], sentObject.nestedList![i]),
+      //      true);
+      //}
+      expect(
+          mapEquals(
+              echoObject.mapWithAnnotations, sentObject.mapWithAnnotations),
+          true);
+      expect(
+          mapEquals(echoObject.mapWithObject, sentObject.mapWithObject), true);
+    });
+  });
+
+  group('Flutter API tests', () {
+    // TODO(stuartmorgan): Add Flutter API tests, driven by wrapper host APIs
+    // that forward the arguments and return values in the opposite direction.
+  });
+}

packages/pigeon/platform_tests/shared_test_plugin_code/pubspec.yaml

@@ -0,0 +1,19 @@
+name: shared_test_plugin_code
+description: Common code for test_plugin and altenate_language_test_plugin
+version: 0.0.1
+publish_to: none
+
+environment:
+  sdk: '>=2.18.0 <3.0.0'
+  flutter: ">=3.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  # These are normal dependencies rather than dev_dependencies because the
+  # package exports the integration test code to be shared by the integration
+  # tests for the two plugins.
+  flutter_test:
+    sdk: flutter
+  integration_test:
+    sdk: flutter

packages/pigeon/platform_tests/test_plugin/example/integration_test/test.dart

@@ -2,78 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(a14n): remove this import once Flutter 3.1 or later reaches stable (including flutter/flutter#104231)
-// ignore: unnecessary_import
-import 'dart:typed_data';
+import 'package:shared_test_plugin_code/integration_tests.dart';
 
-import 'package:flutter/foundation.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:integration_test/integration_test.dart';
-import 'package:test_plugin/all_datatypes.gen.dart';
-import 'package:test_plugin/all_void.gen.dart';
-
-void main() {
-  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
-
-  group('Host API tests', () {
-    testWidgets('voidCallVoidReturn', (WidgetTester _) async {
-      final AllVoidHostApi api = AllVoidHostApi();
-
-      expect(api.doit(), completes);
-    });
-
-    testWidgets('allDataTypesEcho', (WidgetTester _) async {
-      final HostEverything api = HostEverything();
-
-      final Everything sentObject = Everything(
-        aBool: true,
-        anInt: 42,
-        aDouble: 3.14159,
-        aString: 'Hello host!',
-        aByteArray: Uint8List.fromList(<int>[1, 2, 3]),
-        a4ByteArray: Int32List.fromList(<int>[4, 5, 6]),
-        a8ByteArray: Int64List.fromList(<int>[7, 8, 9]),
-        aFloatArray: Float64List.fromList(<double>[2.71828, 3.14159]),
-        aList: <Object?>['Thing 1', 2],
-        aMap: <Object?, Object?>{'a': 1, 'b': 2.0},
-        nestedList: <List<bool>>[
-          <bool>[true, false],
-          <bool>[false, true]
-        ],
-      );
-
-      final Everything echoObject = await api.echo(sentObject);
-      expect(echoObject.aBool, sentObject.aBool);
-      expect(echoObject.anInt, sentObject.anInt);
-      expect(echoObject.aDouble, sentObject.aDouble);
-      expect(echoObject.aString, sentObject.aString);
-      // TODO(stuartmorgan): Enable these once they work for all generators;
-      // currently at least Swift is broken.
-      // See https://github.com/flutter/flutter/issues/115906
-      //expect(echoObject.aByteArray, sentObject.aByteArray);
-      //expect(echoObject.a4ByteArray, sentObject.a4ByteArray);
-      //expect(echoObject.a8ByteArray, sentObject.a8ByteArray);
-      //expect(echoObject.aFloatArray, sentObject.aFloatArray);
-      expect(listEquals(echoObject.aList, sentObject.aList), true);
-      expect(mapEquals(echoObject.aMap, sentObject.aMap), true);
-      expect(echoObject.nestedList?.length, sentObject.nestedList?.length);
-      // TODO(stuartmorgan): Enable this once the Dart types are fixed; see
-      // https://github.com/flutter/flutter/issues/116117
-      //for (int i = 0; i < echoObject.nestedList!.length; i++) {
-      //  expect(listEquals(echoObject.nestedList![i], sentObject.nestedList![i]),
-      //      true);
-      //}
-      expect(
-          mapEquals(
-              echoObject.mapWithAnnotations, sentObject.mapWithAnnotations),
-          true);
-      expect(
-          mapEquals(echoObject.mapWithObject, sentObject.mapWithObject), true);
-    });
-  });
-
-  group('Flutter API tests', () {
-    // TODO(stuartmorgan): Add Flutter API tests, driven by wrapper host APIs
-    // that forward the arguments and return values in the opposite direction.
-  });
-}
+void main() => runPigeonIntegrationTests();

packages/pigeon/platform_tests/test_plugin/example/lib/main.dart

@@ -2,61 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// ignore_for_file: public_member_api_docs
-
 import 'package:flutter/material.dart';
-import 'package:test_plugin/all_void.gen.dart';
-import 'package:test_plugin/test_plugin.dart';
+import 'package:shared_test_plugin_code/example_app.dart';
 
 void main() {
-  runApp(const MyApp());
-}
-
-class MyApp extends StatefulWidget {
-  const MyApp({super.key});
-
-  @override
-  State<MyApp> createState() => _MyAppState();
-}
-
-class _MyAppState extends State<MyApp> {
-  // ignore: unused_field
-  final TestPlugin _testPlugin = TestPlugin();
-  late final AllVoidHostApi api;
-  String status = 'Calling...';
-
-  @override
-  void initState() {
-    super.initState();
-    initPlatformState();
-  }
-
-  Future<void> initPlatformState() async {
-    api = AllVoidHostApi();
-    try {
-      await api.doit();
-    } catch (e) {
-      setState(() {
-        status = 'Failed: $e';
-      });
-      return;
-    }
-    setState(() {
-      status = 'Success!';
-    });
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return MaterialApp(
-      home: Scaffold(
-        appBar: AppBar(
-          title: const Text('Pigeon integration tests'),
-        ),
-        body: Center(
-          child: Text(status),
-        ),
-      ),
-    );
-  }
+  runApp(const ExampleApp());
 }

packages/pigeon/platform_tests/test_plugin/example/pubspec.yaml

@@ -8,6 +8,8 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+  shared_test_plugin_code:
+    path: ../../shared_test_plugin_code
   test_plugin:
     path: ../
 

packages/pigeon/platform_tests/test_plugin/lib/test_plugin.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(tarrinneal): Add integration tests.
-
-/// A host plugin for Pigeon tests.
-class TestPlugin {}
+// There is intentionally no code here; tests use generated Pigeon APIs
+// directly, as wrapping them in a plugin would just add maintenance burden
+// when changing tests.

packages/pigeon/run_tests.sh

@@ -251,6 +251,10 @@ run_android_unittests() {
   popd
 }
 
+run_android_java_e2e_tests() {
+  dart run tool/run_tests.dart -t android_java_integration_tests --skip-generation
+}
+
 ###############################################################################
 # main
 ###############################################################################
@@ -267,6 +271,7 @@ should_run_macos_swift_e2e_tests=true
 should_run_android_kotlin_unittests=true
 # Default to false until there is CI support. See
 # https://github.com/flutter/flutter/issues/111505
+should_run_android_java_e2e_tests=false
 should_run_android_kotlin_e2e_tests=false
 while getopts "t:l?h" opt; do
   case $opt in
@@ -282,10 +287,12 @@ while getopts "t:l?h" opt; do
     should_run_macos_swift_unittests=false
     should_run_macos_swift_e2e_tests=false
     should_run_android_kotlin_unittests=false
+    should_run_android_java_e2e_tests=false
     should_run_android_kotlin_e2e_tests=false
     case $OPTARG in
     # TODO(stuartmorgan): Rename to include "java".
     android_unittests) should_run_android_unittests=true ;;
+    android_java_e2e_tests) should_run_android_java_e2e_tests=true ;;
     dart_compilation_tests) should_run_dart_compilation_tests=true ;;
     dart_unittests) should_run_dart_unittests=true ;;
     flutter_unittests) should_run_flutter_unittests=true ;;
@@ -307,6 +314,7 @@ while getopts "t:l?h" opt; do
   l)
     echo "available tests for -t:
   android_unittests        - Unit tests on generated Java code.
+  android_java_e2e_tests   - Integration tests on generated Java code on Android.
   android_kotlin_unittests - Unit tests on generated Kotlin code on Android.
   android_kotlin_e2e_tests - Integration tests on generated Kotlin code on Android.
   dart_compilation_tests   - Compilation tests on generated Dart code.
@@ -371,6 +379,9 @@ fi
 if [ "$should_run_android_unittests" = true ]; then
   run_android_unittests
 fi
+if [ "$should_run_android_java_e2e_tests" = true ]; then
+  run_android_java_e2e_tests
+fi
 if [ "$should_run_macos_swift_unittests" = true ]; then
   run_macos_swift_unittests
 fi

packages/pigeon/tool/run_tests.dart

@@ -28,6 +28,8 @@ const String _skipGenerationFlag = 'skip-generation';
 const int _noDeviceAvailableExitCode = 100;
 
 const String _testPluginRelativePath = 'platform_tests/test_plugin';
+const String _alternateLanguageTestPluginRelativePath =
+    'platform_tests/test_plugin';
 const String _integrationTestFileRelativePath = 'integration_test/test.dart';
 
 @immutable
@@ -44,9 +46,12 @@ const Map<String, _TestInfo> _tests = <String, _TestInfo>{
   'windows_integration_tests': _TestInfo(
       function: _runWindowsIntegrationTests,
       description: 'Integration tests on generated Windows C++ code.'),
-  'android_unittests': _TestInfo(
-      function: _runAndroidUnitTests,
+  'android_java_unittests': _TestInfo(
+      function: _runAndroidJavaUnitTests,
       description: 'Unit tests on generated Java code.'),
+  'android_java_integration_tests': _TestInfo(
+      function: _runAndroidJavaIntegrationTests,
+      description: 'Integration tests on generated Java code.'),
   'android_kotlin_unittests': _TestInfo(
       function: _runAndroidKotlinUnitTests,
       description: 'Unit tests on generated Kotlin code.'),
@@ -79,10 +84,14 @@ const Map<String, _TestInfo> _tests = <String, _TestInfo>{
       description: 'Unit tests on generated Dart mock handler code.'),
 };
 
-Future<int> _runAndroidUnitTests() async {
+Future<int> _runAndroidJavaUnitTests() async {
   throw UnimplementedError('See run_tests.sh.');
 }
 
+Future<int> _runAndroidJavaIntegrationTests() async {
+  return _runAndroidIntegrationTests(_alternateLanguageTestPluginRelativePath);
+}
+
 Future<int> _runAndroidKotlinUnitTests() async {
   const String examplePath = './$_testPluginRelativePath/example';
   const String androidProjectPath = '$examplePath/android';
@@ -98,6 +107,10 @@ Future<int> _runAndroidKotlinUnitTests() async {
 }
 
 Future<int> _runAndroidKotlinIntegrationTests() async {
+  return _runAndroidIntegrationTests(_testPluginRelativePath);
+}
+
+Future<int> _runAndroidIntegrationTests(String testPluginPath) async {
   final String? device = await getDeviceForPlatform('android');
   if (device == null) {
     print('No Android device available. Attach an Android device or start '
@@ -105,7 +118,7 @@ Future<int> _runAndroidKotlinIntegrationTests() async {
     return _noDeviceAvailableExitCode;
   }
 
-  const String examplePath = './$_testPluginRelativePath/example';
+  final String examplePath = './$testPluginPath/example';
   return runFlutterCommand(
     examplePath,
     'test',

packages/pigeon/tool/shared/generation.dart

@@ -77,6 +77,8 @@ Future<int> generatePigeons({required String baseDir}) async {
   final String outputBase = p.join(baseDir, 'platform_tests', 'test_plugin');
   final String alternateOutputBase =
       p.join(baseDir, 'platform_tests', 'alternate_language_test_plugin');
+  final String sharedDartOutputBase =
+      p.join(baseDir, 'platform_tests', 'shared_test_plugin_code');
   // TODO(stuartmorgan): Eliminate this and use alternateOutputBase.
   // See https://github.com/flutter/packages/pull/2816.
   final String iosObjCBase =
@@ -90,7 +92,7 @@ Future<int> generatePigeons({required String baseDir}) async {
     // Generate the default language test plugin output.
     int generateCode = await runPigeon(
       input: './pigeons/$input.dart',
-      dartOut: '$outputBase/lib/$input.gen.dart',
+      dartOut: '$sharedDartOutputBase/lib/src/generated/$input.gen.dart',
       // Android
       kotlinOut: skipLanguages.contains(GeneratorLanguages.kotlin)
           ? null
@@ -129,7 +131,6 @@ Future<int> generatePigeons({required String baseDir}) async {
     // Generate the alternate language test plugin output.
     generateCode = await runPigeon(
       input: './pigeons/$input.dart',
-      dartOut: '$alternateOutputBase/lib/$input.gen.dart',
       // Android
       // This doesn't use the '.gen' suffix since Java has strict file naming
       // rules.