[flutter_tools] generate empty plugin registrants for winuwp and fix local...

[flutter_tools] generate empty plugin registrants for winuwp and fix local engine for winuwp_ (#79827)

packages/flutter_tools/bin/tool_backend.dart

@@ -61,8 +61,9 @@ or
     else
       'flutter'
   ]);
-  final String bundlePlatform = targetPlatform == 'windows-x64' ? 'windows' : targetPlatform;
-  final String target = '${buildMode}_bundle_${bundlePlatform}_assets';
+  final bool uwp = targetPlatform.contains('uwp');
+  final String bundlePlatform = targetPlatform.startsWith('windows-x64') ? 'windows' : targetPlatform;
+  final String target = '${buildMode}_bundle_${bundlePlatform}_assets${uwp ? '_uwp' : ''}';
   final Process assembleProcess = await Process.start(
     flutterExecutable,
     <String>[

packages/flutter_tools/lib/src/build_system/targets/windows.dart

@@ -28,7 +28,20 @@ const List<String> _kWindowsArtifacts = <String>[
   'flutter_windows.h',
 ];
 
+const List<String> _kWindowsUwpArtifacts = <String>[
+  'flutter_windows_winuwp.dll',
+  'flutter_windows_winuwp.dll.exp',
+  'flutter_windows_winuwp.dll.lib',
+  'flutter_windows_winuwp.dll.pdb',
+  'flutter_export.h',
+  'flutter_messenger.h',
+  'flutter_plugin_registrar.h',
+  'flutter_texture_registrar.h',
+  'flutter_windows.h',
+];
+
 const String _kWindowsDepfile = 'windows_engine_sources.d';
+const String _kWindowsUwpDepfile = 'windows_uwp_engine_sources.d';
 
 /// Copies the Windows desktop embedding files to the copy directory.
 class UnpackWindows extends Target {
@@ -96,6 +109,82 @@ class UnpackWindows extends Target {
   }
 }
 
+
+/// Copies the Windows desktop embedding files to the copy directory.
+class UnpackWindowsUwp extends Target {
+  const UnpackWindowsUwp();
+
+  @override
+  String get name => 'unpack_windows_uwp';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/windows.dart'),
+  ];
+
+  @override
+  List<Source> get outputs => const <Source>[];
+
+  @override
+  List<String> get depfiles => const <String>[_kWindowsUwpDepfile];
+
+  @override
+  List<Target> get dependencies => const <Target>[];
+
+  @override
+  Future<void> build(Environment environment) async {
+    // These artifact look ups need to modified to windows-x64-uwp once
+    // the cache updates have landed.
+    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
+    final String engineSourcePath = environment.artifacts
+      .getArtifactPath(
+        Artifact.windowsDesktopPath,
+        platform: TargetPlatform.windows_x64,
+        mode: buildMode,
+      );
+    final String clientSourcePath = environment.artifacts
+      .getArtifactPath(
+        Artifact.windowsCppClientWrapper,
+        platform: TargetPlatform.windows_x64,
+        mode: buildMode,
+      );
+    final Directory outputDirectory = environment.fileSystem.directory(
+      environment.fileSystem.path.join(
+        environment.projectDir.path,
+        'winuwp',
+        'flutter',
+        'ephemeral',
+      ),
+    );
+    final Depfile depfile = unpackDesktopArtifacts(
+      fileSystem: environment.fileSystem,
+      artifacts: _kWindowsUwpArtifacts,
+      engineSourcePath: engineSourcePath,
+      outputDirectory: outputDirectory,
+      clientSourcePaths: <String>[clientSourcePath],
+      icuDataPath: environment.artifacts.getArtifactPath(
+        Artifact.icuData,
+        platform: TargetPlatform.windows_x64
+      )
+    );
+    // Copy flutter_windows.h into flutter directory as well.
+    final File flutterWindows = outputDirectory.childFile('flutter_windows.h');
+    final File flutterWindowsDest = flutterWindows.parent.parent.childFile('flutter_windows.h');
+    flutterWindows.copySync(flutterWindowsDest.path);
+    depfile.outputs.add(flutterWindowsDest);
+    //
+
+    final DepfileService depfileService = DepfileService(
+      fileSystem: environment.fileSystem,
+      logger: environment.logger,
+    );
+    depfileService.writeToFile(
+      depfile,
+      environment.buildDir.childFile(_kWindowsUwpDepfile),
+    );
+  }
+}
+
 /// Creates a bundle for the Windows desktop target.
 abstract class BundleWindowsAssets extends Target {
   const BundleWindowsAssets();
@@ -151,6 +240,18 @@ abstract class BundleWindowsAssets extends Target {
   }
 }
 
+
+/// Creates a bundle for the Windows desktop target.
+abstract class BundleWindowsAssetsUwp extends BundleWindowsAssets {
+  const BundleWindowsAssetsUwp();
+
+  @override
+  List<Target> get dependencies => const <Target>[
+    KernelSnapshot(),
+    UnpackWindowsUwp(),
+  ];
+}
+
 /// A wrapper for AOT compilation that copies app.so into the output directory.
 class WindowsAotBundle extends Target {
   /// Create a [WindowsAotBundle] wrapper for [aotTarget].
@@ -236,3 +337,53 @@ class DebugBundleWindowsAssets extends BundleWindowsAssets {
     const Source.pattern('{OUTPUT_DIR}/flutter_assets/kernel_blob.bin'),
   ];
 }
+
+
+class ReleaseBundleWindowsAssetsUwp extends BundleWindowsAssetsUwp {
+  const ReleaseBundleWindowsAssetsUwp();
+
+  @override
+  String get name => 'release_bundle_windows_assets_uwp';
+
+  @override
+  List<Source> get outputs => const <Source>[];
+
+  @override
+  List<Target> get dependencies => <Target>[
+    ...super.dependencies,
+    const WindowsAotBundle(AotElfRelease(TargetPlatform.windows_x64)),
+  ];
+}
+
+class ProfileBundleWindowsAssetsUwp extends BundleWindowsAssetsUwp {
+  const ProfileBundleWindowsAssetsUwp();
+
+  @override
+  String get name => 'profile_bundle_windows_assets_uwp';
+
+  @override
+  List<Source> get outputs => const <Source>[];
+
+  @override
+  List<Target> get dependencies => <Target>[
+    ...super.dependencies,
+    const WindowsAotBundle(AotElfProfile(TargetPlatform.windows_x64)),
+  ];
+}
+
+class DebugBundleWindowsAssetsUwp extends BundleWindowsAssetsUwp {
+  const DebugBundleWindowsAssetsUwp();
+
+  @override
+  String get name => 'debug_bundle_windows_assets_uwp';
+
+  @override
+  List<Source> get inputs => <Source>[
+    const Source.pattern('{BUILD_DIR}/app.dill'),
+  ];
+
+  @override
+  List<Source> get outputs => <Source>[
+    const Source.pattern('{OUTPUT_DIR}/flutter_assets/kernel_blob.bin'),
+  ];
+}

packages/flutter_tools/lib/src/commands/assemble.dart

@@ -79,6 +79,10 @@ List<Target> _kDefaultTargets = <Target>[
   const DebugBundleWindowsAssets(),
   const ProfileBundleWindowsAssets(),
   const ReleaseBundleWindowsAssets(),
+  // Windows UWP targets
+  const DebugBundleWindowsAssetsUwp(),
+  const ProfileBundleWindowsAssetsUwp(),
+  const ReleaseBundleWindowsAssetsUwp(),
 ];
 
 // TODO(ianh): https://github.com/dart-lang/args/issues/181 will allow us to remove useLegacyNames

packages/flutter_tools/lib/src/commands/create_base.dart

@@ -431,7 +431,7 @@ abstract class CreateBase extends FlutterCommand {
         macOSPlatform: templateContext['macos'] as bool ?? false,
         windowsPlatform: templateContext['windows'] as bool ?? false,
         webPlatform: templateContext['web'] as bool ?? false,
-        windowsUwpPlatform: templateContext['winuwp'] as bool ?? false,
+        winUwpPlatform: templateContext['winuwp'] as bool ?? false,
       );
     }
     if (templateContext['android'] == true) {

packages/flutter_tools/lib/src/plugins.dart

@@ -1003,7 +1003,7 @@ List<Plugin> _filterNativePlugins(List<Plugin> plugins, String platformKey) {
 }
 
 Future<void> _writeWindowsPluginFiles(FlutterProject project, List<Plugin> plugins) async {
-  final List<Plugin>nativePlugins = _filterNativePlugins(plugins, WindowsPlugin.kConfigKey);
+  final List<Plugin> nativePlugins = _filterNativePlugins(plugins, WindowsPlugin.kConfigKey);
   final List<Map<String, dynamic>> windowsPlugins = _extractPlatformMaps(nativePlugins, WindowsPlugin.kConfigKey);
   final Map<String, dynamic> context = <String, dynamic>{
     'os': 'windows',
@@ -1014,6 +1014,21 @@ Future<void> _writeWindowsPluginFiles(FlutterProject project, List<Plugin> plugi
   await _writePluginCmakefile(project.windows.generatedPluginCmakeFile, context);
 }
 
+/// The tooling does not currently support any UWP plugins.
+///
+/// Always generates an empty file to satisfy the cmake template.
+Future<void> _writeWindowsUwpPluginFiles(FlutterProject project, List<Plugin> plugins) async {
+  final List<Plugin> nativePlugins = <Plugin>[];
+  final List<Map<String, dynamic>> windowsPlugins = _extractPlatformMaps(nativePlugins, WindowsPlugin.kConfigKey);
+  final Map<String, dynamic> context = <String, dynamic>{
+    'os': 'windows',
+    'plugins': windowsPlugins,
+    'pluginsDir': _cmakeRelativePluginSymlinkDirectoryPath(project.windowsUwp),
+  };
+  await _writeCppPluginRegistrant(project.windowsUwp.managedDirectory, context);
+  await _writePluginCmakefile(project.windowsUwp.generatedPluginCmakeFile, context);
+}
+
 Future<void> _writeCppPluginRegistrant(Directory destination, Map<String, dynamic> templateContext) async {
   final String registryDirectory = destination.path;
   _renderTemplateToFile(
@@ -1078,6 +1093,13 @@ void createPluginSymlinks(FlutterProject project, {bool force = false}) {
       force: force,
     );
   }
+  if (featureFlags.isWindowsUwpEnabled && project.windowsUwp.existsSync()) {
+    _createPlatformPluginSymlinks(
+      project.windowsUwp.pluginSymlinkDirectory,
+      <dynamic>[],
+      force: force,
+    );
+  }
 }
 
 /// Handler for symlink failures which provides specific instructions for known
@@ -1170,6 +1192,7 @@ Future<void> injectPlugins(
   bool linuxPlatform = false,
   bool macOSPlatform = false,
   bool windowsPlatform = false,
+  bool winUwpPlatform = false,
   bool webPlatform = false,
 }) async {
   final List<Plugin> plugins = await findPlugins(project);
@@ -1190,6 +1213,9 @@ Future<void> injectPlugins(
   if (windowsPlatform) {
     await _writeWindowsPluginFiles(project, plugins);
   }
+  if (winUwpPlatform) {
+    await _writeWindowsUwpPluginFiles(project, plugins);
+  }
   if (!project.isModule) {
     final List<XcodeBasedProject> darwinProjects = <XcodeBasedProject>[
       if (iosPlatform) project.ios,

packages/flutter_tools/lib/src/project.dart

@@ -279,6 +279,7 @@ class FlutterProject {
       macOSPlatform: featureFlags.isMacOSEnabled && macos.existsSync(),
       windowsPlatform: featureFlags.isWindowsEnabled && windows.existsSync(),
       webPlatform: featureFlags.isWebEnabled && web.existsSync(),
+      winUwpPlatform: featureFlags.isWindowsUwpEnabled && windowsUwp.existsSync(),
     );
   }
 
@@ -291,7 +292,7 @@ class FlutterProject {
     bool macOSPlatform = false,
     bool windowsPlatform = false,
     bool webPlatform = false,
-    bool windowsUwpPlatform = false,
+    bool winUwpPlatform = false,
   }) async {
     if (!directory.existsSync() || hasExampleApp || isPlugin) {
       return;
@@ -315,7 +316,7 @@ class FlutterProject {
     if (webPlatform) {
       await web.ensureReadyForPlatformSpecificTooling();
     }
-    if (windowsUwpPlatform) {
+    if (winUwpPlatform) {
       await windowsUwp.ensureReadyForPlatformSpecificTooling();
     }
     await injectPlugins(
@@ -326,6 +327,7 @@ class FlutterProject {
       macOSPlatform: macOSPlatform,
       windowsPlatform: windowsPlatform,
       webPlatform: webPlatform,
+      winUwpPlatform: winUwpPlatform,
     );
   }
 

packages/flutter_tools/lib/src/runner/local_engine.dart

@@ -152,6 +152,10 @@ class LocalEngineLocator {
   // Determine the host engine directory associated with the local engine:
   // Strip '_sim_' since there are no host simulator builds.
   String _getHostEngineBasename(String localEngineBasename) {
+    // Allow winuwp builds to be treated as host builds.
+    if (localEngineBasename.startsWith('winuwp')) {
+      return localEngineBasename;
+    }
     String tmpBasename = localEngineBasename.replaceFirst('_sim_', '_');
     tmpBasename = tmpBasename.substring(tmpBasename.indexOf('_') + 1);
     // Strip suffix for various archs.

packages/flutter_tools/lib/src/windows/build_windows.dart

@@ -150,11 +150,13 @@ Future<void> buildWindowsUwp(WindowsUwpProject windowsProject, BuildInfo buildIn
   }
 
   final Directory buildDirectory = globals.fs.directory(getWindowsBuildUwpDirectory());
+  final String buildModeName = getNameForBuildMode(buildInfo.mode ?? BuildMode.release);
   final Status status = globals.logger.startProgress(
     'Building Windows application...',
   );
   try {
     await _runCmakeGeneration(cmakePath, buildDirectory, windowsProject.cmakeFile.parent);
+    await _runBuild(cmakePath, buildDirectory, buildModeName, install: false);
   } finally {
     status.cancel();
   }
@@ -188,7 +190,12 @@ Future<void> _runCmakeGeneration(String cmakePath, Directory buildDir, Directory
   globals.flutterUsage.sendTiming('build', 'windows-cmake-generation', Duration(milliseconds: sw.elapsedMilliseconds));
 }
 
-Future<void> _runBuild(String cmakePath, Directory buildDir, String buildModeName) async {
+Future<void> _runBuild(
+  String cmakePath,
+  Directory buildDir,
+  String buildModeName,
+  { bool install = true }
+) async {
   final Stopwatch sw = Stopwatch()..start();
 
   // MSBuild sends all output to stdout, including build errors. This surfaces
@@ -204,8 +211,8 @@ Future<void> _runBuild(String cmakePath, Directory buildDir, String buildModeNam
         buildDir.path,
         '--config',
         toTitleCase(buildModeName),
-        '--target',
-        'INSTALL',
+        if (install)
+          ...<String>['--target', 'INSTALL'],
         if (globals.logger.isVerbose)
           '--verbose'
       ],

packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart

@@ -107,16 +107,20 @@ void main() {
     bool verbose = false,
     void Function() onRun,
     String stdout = '',
+    bool winuwp = false,
   }) {
     return FakeCommand(
       command: <String>[
         cmakePath,
         '--build',
+        if (winuwp)
+          r'build\winuwp'
+        else
           r'build\windows',
         '--config',
         buildMode,
-        '--target',
-        'INSTALL',
+        if (!winuwp)
+          ...<String>['--target', 'INSTALL'],
         if (verbose)
           '--verbose'
       ],
@@ -498,7 +502,10 @@ C:\foo\windows\runner\main.cpp(17,1): error C2065: 'Baz': undeclared identifier
   }, overrides: <Type, Generator>{
     Platform: () => windowsPlatform,
     FileSystem: () => fileSystem,
-    ProcessManager: () => FakeProcessManager.list(<FakeCommand>[cmakeGenerationCommand(winuwp: true)]),
+    ProcessManager: () => FakeProcessManager.list(<FakeCommand>[
+      cmakeGenerationCommand(winuwp: true),
+      buildCommand('Release',  stdout: 'STDOUT STUFF', winuwp: true),
+    ]),
     FeatureFlags: () => TestFeatureFlags(isWindowsUwpEnabled: true),
   });
 }

packages/flutter_tools/test/general.shard/build_system/targets/windows_test.dart

@@ -27,7 +27,7 @@ final Platform kWindowsPlatform = FakePlatform(
 );
 
 void main() {
-  testWithoutContext('UnpackWindows copies files to the correct cache directory', () async {
+  testWithoutContext('UnpackWindows copies files to the correct windows/ cache directory', () async {
     final Artifacts artifacts = Artifacts.test();
     final FileSystem fileSystem = MemoryFileSystem.test(style: FileSystemStyle.windows);
     final Environment environment = Environment.test(
@@ -126,6 +126,107 @@ void main() {
     ]));
   });
 
+  testWithoutContext('UnpackWindowsUwp copies files to the correct winuwp/ cache directory', () async {
+    final Artifacts artifacts = Artifacts.test();
+    final FileSystem fileSystem = MemoryFileSystem.test(style: FileSystemStyle.windows);
+    final Environment environment = Environment.test(
+      fileSystem.currentDirectory,
+      artifacts: artifacts,
+      processManager: FakeProcessManager.any(),
+      fileSystem: fileSystem,
+      logger: BufferLogger.test(),
+      defines: <String, String>{
+        kBuildMode: 'debug',
+      },
+    );
+    final DepfileService depfileService = DepfileService(
+      logger: BufferLogger.test(),
+      fileSystem: fileSystem,
+    );
+    environment.buildDir.createSync(recursive: true);
+
+    final String windowsDesktopPath = artifacts.getArtifactPath(Artifact.windowsDesktopPath, platform: TargetPlatform.windows_x64, mode: BuildMode.debug);
+    final String windowsCppClientWrapper = artifacts.getArtifactPath(Artifact.windowsCppClientWrapper, platform: TargetPlatform.windows_x64, mode: BuildMode.debug);
+    final String icuData = artifacts.getArtifactPath(Artifact.icuData, platform: TargetPlatform.windows_x64);
+    final List<String> requiredFiles = <String>[
+      '$windowsDesktopPath\\flutter_export.h',
+      '$windowsDesktopPath\\flutter_messenger.h',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll.exp',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll.lib',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll.pdb',
+      '$windowsDesktopPath\\flutter_plugin_registrar.h',
+      '$windowsDesktopPath\\flutter_texture_registrar.h',
+      '$windowsDesktopPath\\flutter_windows.h',
+      icuData,
+      '$windowsCppClientWrapper\\foo',
+      r'C:\packages\flutter_tools\lib\src\build_system\targets\windows.dart',
+    ];
+
+    for (final String path in requiredFiles) {
+      fileSystem.file(path).createSync(recursive: true);
+    }
+    fileSystem.directory('windows').createSync();
+
+    await const UnpackWindowsUwp().build(environment);
+
+    // Output files are copied correctly.
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_export.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_messenger.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll.exp'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll.lib'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll.pdb'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_export.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_messenger.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_plugin_registrar.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_texture_registrar.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\ephemeral\flutter_windows.h'), exists);
+    expect(fileSystem.file(r'C:\winuwp\flutter\flutter_windows.h'), exists);
+    expect(fileSystem.file('C:\\winuwp\\flutter\\ephemeral\\$icuData'), exists);
+    expect(fileSystem.file('C:\\winuwp\\flutter\\ephemeral\\$windowsCppClientWrapper\\foo'), exists);
+
+    final File outputDepfile = environment.buildDir
+      .childFile('windows_uwp_engine_sources.d');
+
+    // Depfile is created correctly.
+    expect(outputDepfile, exists);
+
+    final List<String> inputPaths = depfileService.parse(outputDepfile)
+      .inputs.map((File file) => file.path).toList();
+    final List<String> outputPaths = depfileService.parse(outputDepfile)
+      .outputs.map((File file) => file.path).toList();
+
+    // Depfile has expected sources.
+    expect(inputPaths, unorderedEquals(<String>[
+      '$windowsDesktopPath\\flutter_export.h',
+      '$windowsDesktopPath\\flutter_messenger.h',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll.exp',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll.lib',
+      '$windowsDesktopPath\\flutter_windows_winuwp.dll.pdb',
+      '$windowsDesktopPath\\flutter_plugin_registrar.h',
+      '$windowsDesktopPath\\flutter_texture_registrar.h',
+      '$windowsDesktopPath\\flutter_windows.h',
+      icuData,
+      '$windowsCppClientWrapper\\foo',
+    ]));
+    expect(outputPaths, unorderedEquals(<String>[
+      r'C:\winuwp\flutter\ephemeral\flutter_export.h',
+      r'C:\winuwp\flutter\ephemeral\flutter_messenger.h',
+      r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll',
+      r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll.exp',
+      r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll.lib',
+      r'C:\winuwp\flutter\ephemeral\flutter_windows_winuwp.dll.pdb',
+      r'C:\winuwp\flutter\ephemeral\flutter_plugin_registrar.h',
+      r'C:\winuwp\flutter\ephemeral\flutter_texture_registrar.h',
+      r'C:\winuwp\flutter\ephemeral\flutter_windows.h',
+      r'C:\winuwp\flutter\flutter_windows.h',
+      'C:\\winuwp\\flutter\\ephemeral\\$icuData',
+      'C:\\winuwp\\flutter\\ephemeral\\$windowsCppClientWrapper\\foo',
+    ]));
+  });
+
   // AssetBundleFactory still uses context injection
   FileSystem fileSystem;
 

packages/flutter_tools/test/general.shard/runner/local_engine_test.dart

@@ -95,6 +95,31 @@ void main() {
     expect(logger.traceText, contains('Local engine source at /arbitrary/engine/src'));
   });
 
+  testWithoutContext('treats winuwp_debug_unopt as a host engine', () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final Directory localEngine = fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/winuwp_debug_unopt/')
+        ..createSync(recursive: true);
+    fileSystem.directory('$kArbitraryEngineRoot/src/out/winuwp_debug_unopt/').createSync(recursive: true);
+
+    final BufferLogger logger = BufferLogger.test();
+    final LocalEngineLocator localEngineLocator = LocalEngineLocator(
+      fileSystem: fileSystem,
+      flutterRoot: 'flutter/flutter',
+      logger: logger,
+      userMessages: UserMessages(),
+      platform: FakePlatform(environment: <String, String>{}),
+    );
+
+    expect(
+      await localEngineLocator.findEnginePath(null, localEngine.path, null),
+      matchesEngineBuildPaths(
+        hostEngine: '/arbitrary/engine/src/out/winuwp_debug_unopt',
+        targetEngine: '/arbitrary/engine/src/out/winuwp_debug_unopt',
+      ),
+    );
+  });
+
   testWithoutContext('works if --local-engine is specified and --local-engine-src-path '
       'is determined by --local-engine', () async {
     final FileSystem fileSystem = MemoryFileSystem.test();