[flutter_tools] allow device classes to provide platform-specific interface for devFS Sync (#66266)

packages/flutter_tools/lib/src/build_runner/devfs_web.dart

@@ -776,20 +776,21 @@ class WebDevFS implements DevFS {
 
   @override
   Future<UpdateFSReport> update({
-    Uri mainUri,
+    @required Uri mainUri,
+    @required ResidentCompiler generator,
+    @required bool trackWidgetCreation,
+    @required String pathToReload,
+    @required List<Uri> invalidatedFiles,
+    @required PackageConfig packageConfig,
+    DevFSWriter devFSWriter,
     String target,
     AssetBundle bundle,
     DateTime firstBuildTime,
     bool bundleFirstUpload = false,
-    @required ResidentCompiler generator,
     String dillOutputPath,
-    @required bool trackWidgetCreation,
     bool fullRestart = false,
     String projectRootPath,
-    String pathToReload,
-    List<Uri> invalidatedFiles,
     bool skipAssets = false,
-    @required PackageConfig packageConfig,
   }) async {
     assert(trackWidgetCreation != null);
     assert(generator != null);

packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart

@@ -696,6 +696,7 @@ class _ResidentWebRunner extends ResidentWebRunner {
       invalidatedFiles: invalidationResult.uris,
       packageConfig: invalidationResult.packageConfig,
       trackWidgetCreation: debuggingOptions.buildInfo.trackWidgetCreation,
+      devFSWriter: null,
     );
     devFSStatus.stop();
     globals.printTrace('Synced ${getSizeAsMB(report.syncedBytes)}.');

packages/flutter_tools/lib/src/desktop_device.dart

@@ -9,10 +9,12 @@ import 'package:process/process.dart';
 
 import 'application_package.dart';
 import 'base/common.dart';
+import 'base/file_system.dart';
 import 'base/io.dart';
 import 'base/logger.dart';
 import 'build_info.dart';
 import 'convert.dart';
+import 'devfs.dart';
 import 'device.dart';
 import 'globals.dart' as globals;
 import 'protocol_discovery.dart';
@@ -25,8 +27,10 @@ abstract class DesktopDevice extends Device {
       @required bool ephemeral,
       Logger logger,
       ProcessManager processManager,
+      FileSystem fileSystem,
     }) : _logger = logger ?? globals.logger, // TODO(jonahwilliams): remove after updating google3
          _processManager = processManager ?? globals.processManager,
+         _fileSystem = fileSystem ?? globals.fs,
          super(
           identifier,
           category: Category.desktop,
@@ -36,9 +40,13 @@ abstract class DesktopDevice extends Device {
 
   final Logger _logger;
   final ProcessManager _processManager;
+  final FileSystem _fileSystem;
   final Set<Process> _runningProcesses = <Process>{};
   final DesktopLogReader _deviceLogReader = DesktopLogReader();
 
+  DevFSWriter get devFSWriter => _desktopDevFSWriter ??= LocalDevFSWriter(fileSystem: _fileSystem);
+  LocalDevFSWriter _desktopDevFSWriter;
+
   // Since the host and target devices are the same, no work needs to be done
   // to install the application.
   @override

packages/flutter_tools/lib/src/devfs.dart

@@ -209,7 +209,17 @@ class DevFSException implements Exception {
   final StackTrace stackTrace;
 }
 
-class _DevFSHttpWriter {
+/// Interface responsible for syncing asset files to a development device.
+abstract class DevFSWriter {
+  /// Write the assets in [entries] to the target device.
+  ///
+  /// The keys of the map are relative from the [baseUri].
+  ///
+  /// Throws a [DevFSException] if the process fails to complete.
+  Future<void> write(Map<Uri, DevFSContent> entries, Uri baseUri, DevFSWriter parent);
+}
+
+class _DevFSHttpWriter implements DevFSWriter {
   _DevFSHttpWriter(
     this.fsName,
     vm_service.VmService serviceProtocol, {
@@ -235,12 +245,21 @@ class _DevFSHttpWriter {
   Map<Uri, DevFSContent> _outstanding;
   Completer<void> _completer;
 
-  Future<void> write(Map<Uri, DevFSContent> entries) async {
-    _client.maxConnectionsPerHost = kMaxInFlight;
-    _completer = Completer<void>();
-    _outstanding = Map<Uri, DevFSContent>.of(entries);
-    _scheduleWrites();
-    await _completer.future;
+  @override
+  Future<void> write(Map<Uri, DevFSContent> entries, Uri devFSBase, [DevFSWriter parent]) async {
+    try {
+      _client.maxConnectionsPerHost = kMaxInFlight;
+      _completer = Completer<void>();
+      _outstanding = Map<Uri, DevFSContent>.of(entries);
+      _scheduleWrites();
+      await _completer.future;
+    } on SocketException catch (socketException, stackTrace) {
+      _logger.printTrace('DevFS sync failed. Lost connection to device: $socketException');
+      throw DevFSException('Lost connection to device.', socketException, stackTrace);
+    } on Exception catch (exception, stackTrace) {
+      _logger.printError('Could not update files on device: $exception');
+      throw DevFSException('Sync failed', exception, stackTrace);
+    }
   }
 
   void _scheduleWrites() {
@@ -425,6 +444,7 @@ class DevFS {
     @required String pathToReload,
     @required List<Uri> invalidatedFiles,
     @required PackageConfig packageConfig,
+    DevFSWriter devFSWriter,
     String target,
     AssetBundle bundle,
     DateTime firstBuildTime,
@@ -445,7 +465,6 @@ class DevFS {
 
     int syncedBytes = 0;
     if (bundle != null && !skipAssets) {
-      _logger.printTrace('Scanning asset files');
       final String assetBuildDirPrefix = _asUriPath(getAssetBuildDirectory());
       // We write the assets into the AssetBundle working dir so that they
       // are in the same location in DevFS and the iOS simulator.
@@ -503,15 +522,7 @@ class DevFS {
     }
     _logger.printTrace('Updating files');
     if (dirtyEntries.isNotEmpty) {
-      try {
-        await _httpWriter.write(dirtyEntries);
-      } on SocketException catch (socketException, stackTrace) {
-        _logger.printTrace('DevFS sync failed. Lost connection to device: $socketException');
-        throw DevFSException('Lost connection to device.', socketException, stackTrace);
-      } on Exception catch (exception, stackTrace) {
-        _logger.printError('Could not update files on device: $exception');
-        throw DevFSException('Sync failed', exception, stackTrace);
-      }
+      await (devFSWriter ?? _httpWriter).write(dirtyEntries, _baseUri, _httpWriter);
     }
     _logger.printTrace('DevFS: Sync finished');
     return UpdateFSReport(
@@ -525,3 +536,40 @@ class DevFS {
   /// Converts a platform-specific file path to a platform-independent URL path.
   String _asUriPath(String filePath) => _fileSystem.path.toUri(filePath).path + '/';
 }
+
+/// An implementation of a devFS writer which copies physical files for devices
+/// running on the same host.
+///
+/// DevFS entries which correspond to physical files are copied using [File.copySync],
+/// while entries that correspond to arbitrary string/byte values are written from
+/// memory.
+///
+/// Requires that the file system is the same for both the tool and application.
+class LocalDevFSWriter implements DevFSWriter {
+  LocalDevFSWriter({
+    @required FileSystem fileSystem,
+  }) : _fileSystem = fileSystem;
+
+  final FileSystem _fileSystem;
+
+  @override
+  Future<void> write(Map<Uri, DevFSContent> entries, Uri baseUri, [DevFSWriter parent]) async {
+    try {
+      for (final Uri uri in entries.keys) {
+        final DevFSContent devFSContent = entries[uri];
+        final File destination = _fileSystem.file(baseUri.resolveUri(uri));
+        if (!destination.parent.existsSync()) {
+          destination.parent.createSync(recursive: true);
+        }
+        if (devFSContent is DevFSFileContent) {
+          final File content = devFSContent.file as File;
+          content.copySync(destination.path);
+          continue;
+        }
+        destination.writeAsBytesSync(await devFSContent.contentsAsBytes());
+      }
+    } on FileSystemException catch (err) {
+      throw DevFSException(err.toString());
+    }
+  }
+}

packages/flutter_tools/lib/src/device.dart

@@ -368,12 +368,14 @@ class FlutterDeviceManager extends DeviceManager {
       macOSWorkflow: macOSWorkflow,
       logger: logger,
       platform: platform,
+      fileSystem: fileSystem,
     ),
     LinuxDevices(
       platform: platform,
       featureFlags: featureFlags,
       processManager: processManager,
       logger: logger,
+      fileSystem: fileSystem,
     ),
     WindowsDevices(),
     WebDevices(

packages/flutter_tools/lib/src/ios/simulators.dart

@@ -17,6 +17,7 @@ import '../base/process.dart';
 import '../base/utils.dart';
 import '../build_info.dart';
 import '../convert.dart';
+import '../devfs.dart';
 import '../device.dart';
 import '../globals.dart' as globals;
 import '../macos/xcode.dart';
@@ -295,6 +296,9 @@ class IOSSimulator extends Device {
   final SimControl _simControl;
   final Xcode _xcode;
 
+  DevFSWriter get devFSWriter => _desktopDevFSWriter ??= LocalDevFSWriter(fileSystem: globals.fs);
+  LocalDevFSWriter _desktopDevFSWriter;
+
   @override
   Future<bool> get isLocalEmulator async => true;
 

packages/flutter_tools/lib/src/linux/linux_device.dart

@@ -5,6 +5,7 @@
 import 'package:meta/meta.dart';
 import 'package:process/process.dart';
 
+import '../base/file_system.dart';
 import '../base/logger.dart';
 import '../base/platform.dart';
 import '../build_info.dart';
@@ -22,12 +23,14 @@ class LinuxDevice extends DesktopDevice {
   LinuxDevice({
     @required ProcessManager processManager,
     @required Logger logger,
+    @required FileSystem fileSystem,
   }) : super(
       'linux',
       platformType: PlatformType.linux,
       ephemeral: false,
       logger: logger,
       processManager: processManager,
+      fileSystem: fileSystem,
   );
 
   @override
@@ -67,6 +70,7 @@ class LinuxDevices extends PollingDeviceDiscovery {
   LinuxDevices({
     @required Platform platform,
     @required FeatureFlags featureFlags,
+    FileSystem fileSystem,
     ProcessManager processManager,
     Logger logger,
   }) : _platform = platform ?? globals.platform, // TODO(jonahwilliams): remove after google3 roll
@@ -74,6 +78,7 @@ class LinuxDevices extends PollingDeviceDiscovery {
           platform: platform,
           featureFlags: featureFlags,
        ),
+       _fileSystem = fileSystem ?? globals.fs,
        _logger = logger,
        _processManager = processManager ?? globals.processManager,
        super('linux devices');
@@ -82,6 +87,7 @@ class LinuxDevices extends PollingDeviceDiscovery {
   final LinuxWorkflow _linuxWorkflow;
   final ProcessManager _processManager;
   final Logger _logger;
+  final FileSystem _fileSystem;
 
   @override
   bool get supportsPlatform => _platform.isLinux;
@@ -98,6 +104,7 @@ class LinuxDevices extends PollingDeviceDiscovery {
       LinuxDevice(
         logger: _logger,
         processManager: _processManager,
+        fileSystem: _fileSystem,
       ),
     ];
   }

packages/flutter_tools/lib/src/macos/macos_device.dart

@@ -5,12 +5,14 @@
 import 'package:meta/meta.dart';
 import 'package:process/process.dart';
 
+import '../base/file_system.dart';
 import '../base/io.dart';
 import '../base/logger.dart';
 import '../base/platform.dart';
 import '../build_info.dart';
 import '../desktop_device.dart';
 import '../device.dart';
+import '../globals.dart' as globals;
 import '../macos/application_package.dart';
 import '../project.dart';
 import 'build_macos.dart';
@@ -21,6 +23,7 @@ class MacOSDevice extends DesktopDevice {
   MacOSDevice({
     @required ProcessManager processManager,
     @required Logger logger,
+    FileSystem fileSystem,
   }) : _processManager = processManager,
        _logger = logger,
        super(
@@ -29,6 +32,7 @@ class MacOSDevice extends DesktopDevice {
         ephemeral: false,
         processManager: processManager,
         logger: logger,
+        fileSystem: fileSystem ?? globals.fs,
       );
 
   final ProcessManager _processManager;
@@ -89,16 +93,19 @@ class MacOSDevices extends PollingDeviceDiscovery {
     @required MacOSWorkflow macOSWorkflow,
     @required ProcessManager processManager,
     @required Logger logger,
+    FileSystem fileSystem,
   }) : _logger = logger,
        _platform = platform,
        _macOSWorkflow = macOSWorkflow,
        _processManager = processManager,
+       _fileSystem = fileSystem ?? globals.fs,
        super('macOS devices');
 
   final MacOSWorkflow _macOSWorkflow;
   final Platform _platform;
   final ProcessManager _processManager;
   final Logger _logger;
+  final FileSystem _fileSystem;
 
   @override
   bool get supportsPlatform => _platform.isMacOS;
@@ -112,7 +119,11 @@ class MacOSDevices extends PollingDeviceDiscovery {
       return const <Device>[];
     }
     return <Device>[
-      MacOSDevice(processManager: _processManager, logger: _logger),
+      MacOSDevice(
+        processManager: _processManager,
+        logger: _logger,
+        fileSystem: _fileSystem,
+      ),
     ];
   }
 

packages/flutter_tools/lib/src/resident_runner.dart

@@ -697,6 +697,7 @@ class FlutterDevice {
         pathToReload: pathToReload,
         invalidatedFiles: invalidatedFiles,
         packageConfig: packageConfig,
+        devFSWriter: null,
       );
     } on DevFSException {
       devFSStatus.cancel();

packages/flutter_tools/test/general.shard/devfs_test.dart

@@ -6,6 +6,7 @@ import 'dart:convert';
 
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
+import 'package:file_testing/file_testing.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
@@ -256,6 +257,81 @@ void main() {
     expect(report.success, true);
     expect(devFS.lastCompiled, isNot(previousCompile));
   });
+
+   testWithoutContext('DevFS uses provided DevFSWriter instead of default HTTP writer', () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final FakeDevFSWriter writer = FakeDevFSWriter();
+    final FakeVmServiceHost fakeVmServiceHost = FakeVmServiceHost(
+      requests: <VmServiceExpectation>[createDevFSRequest],
+    );
+
+    final DevFS devFS = DevFS(
+      fakeVmServiceHost.vmService,
+      'test',
+      fileSystem.currentDirectory,
+      fileSystem: fileSystem,
+      logger: BufferLogger.test(),
+      osUtils: FakeOperatingSystemUtils(),
+      httpClient: MockHttpClient(),
+    );
+
+    await devFS.create();
+
+    final MockResidentCompiler residentCompiler = MockResidentCompiler();
+    when(residentCompiler.recompile(
+      any,
+      any,
+      outputPath: anyNamed('outputPath'),
+      packageConfig: anyNamed('packageConfig'),
+    )).thenAnswer((Invocation invocation) async {
+      fileSystem.file('example').createSync();
+      return const CompilerOutput('lib/foo.txt.dill', 0, <Uri>[]);
+    });
+
+    expect(writer.written, false);
+
+    final UpdateFSReport report = await devFS.update(
+      mainUri: Uri.parse('lib/main.dart'),
+      generator: residentCompiler,
+      dillOutputPath: 'lib/foo.dill',
+      pathToReload: 'lib/foo.txt.dill',
+      trackWidgetCreation: false,
+      invalidatedFiles: <Uri>[],
+      packageConfig: PackageConfig.empty,
+      devFSWriter: writer,
+    );
+
+    expect(report.success, true);
+    expect(writer.written, true);
+  });
+
+  testWithoutContext('Local DevFSwriter can copy and write files', () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final File file = fileSystem.file('foo_bar')
+      ..writeAsStringSync('goodbye');
+    final LocalDevFSWriter writer = LocalDevFSWriter(fileSystem: fileSystem);
+
+    await writer.write(<Uri, DevFSContent>{
+      Uri.parse('hello'): DevFSStringContent('hello'),
+      Uri.parse('goodbye'): DevFSFileContent(file),
+    }, Uri.parse('/foo/bar/devfs/'));
+
+    expect(fileSystem.file('/foo/bar/devfs/hello'), exists);
+    expect(fileSystem.file('/foo/bar/devfs/hello').readAsStringSync(), 'hello');
+    expect(fileSystem.file('/foo/bar/devfs/goodbye'), exists);
+    expect(fileSystem.file('/foo/bar/devfs/goodbye').readAsStringSync(), 'goodbye');
+  });
+
+  testWithoutContext('Local DevFSwriter turns FileSystemException into DevFSException', () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final LocalDevFSWriter writer = LocalDevFSWriter(fileSystem: fileSystem);
+    final File file = MockFile();
+    when(file.copySync(any)).thenThrow(const FileSystemException('foo'));
+
+    await expectLater(() async => await writer.write(<Uri, DevFSContent>{
+      Uri.parse('goodbye'): DevFSFileContent(file),
+    }, Uri.parse('/foo/bar/devfs/')), throwsA(isA<DevFSException>()));
+  });
 }
 
 class MockHttpClientRequest extends Mock implements HttpClientRequest {}
@@ -263,3 +339,12 @@ class MockHttpHeaders extends Mock implements HttpHeaders {}
 class MockHttpClientResponse extends Mock implements HttpClientResponse {}
 class MockOperatingSystemUtils extends Mock implements OperatingSystemUtils {}
 class MockResidentCompiler extends Mock implements ResidentCompiler {}
+class MockFile extends Mock implements File {}
+class FakeDevFSWriter implements DevFSWriter {
+  bool written = false;
+
+  @override
+  Future<void> write(Map<Uri, DevFSContent> entries, Uri baseUri, DevFSWriter parent) async {
+    written = true;
+  }
+}

packages/flutter_tools/test/general.shard/linux/linux_device_test.dart

@@ -31,6 +31,7 @@ void main() {
     final LinuxDevice device = LinuxDevice(
       processManager: FakeProcessManager.any(),
       logger: BufferLogger.test(),
+      fileSystem: MemoryFileSystem.test(),
     );
 
     final PrebuiltLinuxApp linuxApp = PrebuiltLinuxApp(executable: 'foo');
@@ -51,6 +52,7 @@ void main() {
 
   testWithoutContext('LinuxDevice: no devices listed if platform unsupported', () async {
     expect(await LinuxDevices(
+      fileSystem: MemoryFileSystem.test(),
       platform: windows,
       featureFlags: TestFeatureFlags(isLinuxEnabled: true),
       logger: BufferLogger.test(),
@@ -60,6 +62,7 @@ void main() {
 
   testWithoutContext('LinuxDevice: no devices listed if Linux feature flag disabled', () async {
     expect(await LinuxDevices(
+      fileSystem: MemoryFileSystem.test(),
       platform: linux,
       featureFlags: TestFeatureFlags(isLinuxEnabled: false),
       logger: BufferLogger.test(),
@@ -69,6 +72,7 @@ void main() {
 
   testWithoutContext('LinuxDevice: devices', () async {
     expect(await LinuxDevices(
+      fileSystem: MemoryFileSystem.test(),
       platform: linux,
       featureFlags: TestFeatureFlags(isLinuxEnabled: true),
       logger: BufferLogger.test(),
@@ -79,6 +83,7 @@ void main() {
   testWithoutContext('LinuxDevice: discoverDevices', () async {
     // Timeout ignored.
     final List<Device> devices = await LinuxDevices(
+      fileSystem: MemoryFileSystem.test(),
       platform: linux,
       featureFlags: TestFeatureFlags(isLinuxEnabled: true),
       logger: BufferLogger.test(),
@@ -96,6 +101,7 @@ void main() {
     expect(LinuxDevice(
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
+      fileSystem: MemoryFileSystem.test(),
     ).isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
@@ -110,6 +116,7 @@ void main() {
     expect(LinuxDevice(
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
+      fileSystem: MemoryFileSystem.test(),
     ).isSupportedForProject(flutterProject), false);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
@@ -121,6 +128,7 @@ void main() {
     final LinuxDevice device = LinuxDevice(
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
+      fileSystem: MemoryFileSystem.test(),
     );
     const String debugPath = 'debug/executable';
     const String profilePath = 'profile/executable';

packages/flutter_tools/test/general.shard/macos/macos_device_test.dart

@@ -36,6 +36,7 @@ void main() {
     final MacOSDevice device = MacOSDevice(
       processManager: FakeProcessManager.any(),
       logger: BufferLogger.test(),
+      fileSystem: MemoryFileSystem.test(),
     );
     final MockMacOSApp mockMacOSApp = MockMacOSApp();
 
@@ -56,6 +57,7 @@ void main() {
   testUsingContext('Attaches to log reader when running in release mode', () async {
     final Completer<void> completer = Completer<void>();
     final MacOSDevice device = MacOSDevice(
+      fileSystem: MemoryFileSystem.test(),
       processManager: FakeProcessManager.list(<FakeCommand>[
         FakeCommand(
           command: const <String>['Example.app'],
@@ -88,6 +90,7 @@ void main() {
 
   testWithoutContext('No devices listed if platform is unsupported', () async {
     expect(await MacOSDevices(
+      fileSystem: MemoryFileSystem.test(),
       processManager: FakeProcessManager.any(),
       logger: BufferLogger.test(),
       platform: linux,
@@ -100,6 +103,7 @@ void main() {
 
   testWithoutContext('No devices listed if platform is supported and feature is disabled', () async {
     final MacOSDevices macOSDevices = MacOSDevices(
+      fileSystem: MemoryFileSystem.test(),
       processManager: FakeProcessManager.any(),
       logger: BufferLogger.test(),
       platform: macOS,
@@ -114,6 +118,7 @@ void main() {
 
   testWithoutContext('devices listed if platform is supported and feature is enabled', () async {
     final MacOSDevices macOSDevices = MacOSDevices(
+      fileSystem: MemoryFileSystem.test(),
       processManager: FakeProcessManager.any(),
       logger: BufferLogger.test(),
       platform: macOS,
@@ -128,6 +133,7 @@ void main() {
 
   testWithoutContext('can discover devices with a provided timeout', () async {
     final MacOSDevices macOSDevices = MacOSDevices(
+      fileSystem: MemoryFileSystem.test(),
       processManager: FakeProcessManager.any(),
       logger: BufferLogger.test(),
       platform: macOS,
@@ -145,6 +151,7 @@ void main() {
 
   testUsingContext('isSupportedForProject is true with editable host app', () async {
     final MacOSDevice device = MacOSDevice(
+      fileSystem: MemoryFileSystem.test(),
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
     );
@@ -162,6 +169,7 @@ void main() {
 
   testUsingContext('isSupportedForProject is false with no host app', () async {
     final MacOSDevice device = MacOSDevice(
+      fileSystem: MemoryFileSystem.test(),
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
     );
@@ -178,6 +186,7 @@ void main() {
   testUsingContext('executablePathForDevice uses the correct package executable', () async {
     final MockMacOSApp mockApp = MockMacOSApp();
     final MacOSDevice device = MacOSDevice(
+      fileSystem: MemoryFileSystem.test(),
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
     );

packages/flutter_tools/test/general.shard/web/devfs_web_test.dart

@@ -513,6 +513,7 @@ void main() {
       bundleFirstUpload: true,
       invalidatedFiles: <Uri>[],
       packageConfig: PackageConfig.empty,
+      pathToReload: '',
     );
 
     expect(webDevFS.webAssetServer.getFile('require.js'), isNotNull);
@@ -627,6 +628,7 @@ void main() {
       bundleFirstUpload: true,
       invalidatedFiles: <Uri>[],
       packageConfig: PackageConfig.empty,
+      pathToReload: '',
     );
 
     expect(webDevFS.webAssetServer.getFile('require.js'), isNotNull);