Devfs cleanup and testing (#33374)

packages/flutter_tools/bin/fuchsia_asset_builder.dart

@@ -36,10 +36,9 @@ Future<void> main(List<String> args) {
   });
 }
 
-Future<void> writeFile(libfs.File outputFile, DevFSContent content) async {
+void writeFile(libfs.File outputFile, DevFSContent content) {
   outputFile.createSync(recursive: true);
-  final List<int> data = await content.contentsAsBytes();
-  outputFile.writeAsBytesSync(data);
+  content.copyToFile(outputFile);
 }
 
 Future<void> run(List<String> args) async {
@@ -71,12 +70,10 @@ Future<void> run(List<String> args) async {
     exit(1);
   }
 
-  final List<Future<void>> calls = <Future<void>>[];
   assets.entries.forEach((String fileName, DevFSContent content) {
     final libfs.File outputFile = libfs.fs.file(libfs.fs.path.join(assetDir, fileName));
-    calls.add(writeFile(outputFile, content));
+    writeFile(outputFile, content);
   });
-  await Future.wait<void>(calls);
 
   final String outputMan = argResults[_kOptionAssetManifestOut];
   await writeFuchsiaManifest(assets, argResults[_kOptionAsset], outputMan, argResults[_kOptionComponentName]);

packages/flutter_tools/lib/src/bundle.dart

@@ -147,7 +147,7 @@ Future<void> build({
   if (assets == null)
     throwToolExit('Error building assets', exitCode: 1);
 
-  await assemble(
+  assemble(
     buildMode: buildMode,
     assetBundle: assets,
     kernelContent: kernelContent,
@@ -182,14 +182,14 @@ Future<AssetBundle> buildAssets({
   return assetBundle;
 }
 
-Future<void> assemble({
+void assemble({
   BuildMode buildMode,
   AssetBundle assetBundle,
   DevFSContent kernelContent,
   String privateKeyPath = defaultPrivateKeyPath,
   String assetDirPath,
   String compilationTraceFilePath,
-}) async {
+}) {
   assetDirPath ??= getAssetBuildDirectory();
   printTrace('Building bundle');
 
@@ -214,22 +214,21 @@ Future<void> assemble({
   printTrace('Writing asset files to $assetDirPath');
   ensureDirectoryExists(assetDirPath);
 
-  await writeBundle(fs.directory(assetDirPath), assetEntries);
+  writeBundle(fs.directory(assetDirPath), assetEntries);
   printTrace('Wrote $assetDirPath');
 }
 
-Future<void> writeBundle(
+void writeBundle(
   Directory bundleDir,
   Map<String, DevFSContent> assetEntries,
-) async {
+) {
   if (bundleDir.existsSync())
     bundleDir.deleteSync(recursive: true);
   bundleDir.createSync(recursive: true);
 
-  await Future.wait<void>(
-    assetEntries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
+  for (MapEntry<String, DevFSContent> entry in assetEntries.entries) {
     final File file = fs.file(fs.path.join(bundleDir.path, entry.key));
     file.parent.createSync(recursive: true);
-      await file.writeAsBytes(await entry.value.contentsAsBytes());
-    }));
+    entry.value.copyToFile(file);
+  }
 }

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

@@ -242,7 +242,7 @@ class TestCommand extends FastFlutterCommand {
       throwToolExit('Error: Failed to build asset bundle');
     }
     if (_needRebuild(assetBundle.entries)) {
-      await writeBundle(fs.directory(fs.path.join('build', 'unit_test_assets')),
+      writeBundle(fs.directory(fs.path.join('build', 'unit_test_assets')),
           assetBundle.entries);
     }
   }

packages/flutter_tools/lib/src/devfs.dart

@@ -38,21 +38,25 @@ abstract class DevFSContent {
   /// or if the given time is null.
   bool isModifiedAfter(DateTime time);
 
+  /// The number of bytes in this file.
   int get size;
 
-  Future<List<int>> contentsAsBytes();
+  /// Returns the raw bytes of this file.
+  List<int> contentsAsBytes();
 
-  Stream<List<int>> contentsAsStream();
-
-  Stream<List<int>> contentsAsCompressedStream() {
-    return contentsAsStream().cast<List<int>>().transform<List<int>>(gzip.encoder);
+  /// Returns a gzipped representation of the contents of this file.
+  List<int> contentsAsCompressedBytes() {
+    return gzip.encode(contentsAsBytes());
   }
 
-  /// Return the list of files this content depends on.
-  List<String> get fileDependencies => <String>[];
+  /// Copies the content into the provided file.
+  ///
+  /// Requires that the `destination` directory already exists, but the target
+  /// file need not.
+  void copyToFile(File destination);
 }
 
-// File content to be copied to the device.
+/// File content to be copied to the device.
 class DevFSFileContent extends DevFSContent {
   DevFSFileContent(this.file);
 
@@ -102,9 +106,6 @@ class DevFSFileContent extends DevFSContent {
     }
   }
 
-  @override
-  List<String> get fileDependencies => <String>[_getFile().path];
-
   @override
   bool get isModified {
     final FileStat _oldFileStat = _fileStat;
@@ -135,10 +136,12 @@ class DevFSFileContent extends DevFSContent {
   }
 
   @override
-  Future<List<int>> contentsAsBytes() => _getFile().readAsBytes();
+  List<int> contentsAsBytes() => _getFile().readAsBytesSync().cast<int>();
 
   @override
-  Stream<List<int>> contentsAsStream() => _getFile().openRead();
+  void copyToFile(File destination) {
+    _getFile().copySync(destination.path);
+  }
 }
 
 /// Byte content to be copied to the device.
@@ -175,14 +178,15 @@ class DevFSByteContent extends DevFSContent {
   int get size => _bytes.length;
 
   @override
-  Future<List<int>> contentsAsBytes() async => _bytes;
+  List<int> contentsAsBytes() => _bytes;
 
   @override
-  Stream<List<int>> contentsAsStream() =>
-      Stream<List<int>>.fromIterable(<List<int>>[_bytes]);
+  void copyToFile(File destination) {
+    destination.writeAsBytesSync(contentsAsBytes());
+  }
 }
 
-/// String content to be copied to the device.
+/// String content to be copied to the device encoded as utf8.
 class DevFSStringContent extends DevFSByteContent {
   DevFSStringContent(String string)
     : _string = string,
@@ -203,75 +207,29 @@ class DevFSStringContent extends DevFSByteContent {
   }
 }
 
-/// Abstract DevFS operations interface.
-abstract class DevFSOperations {
-  Future<Uri> create(String fsName);
-  Future<dynamic> destroy(String fsName);
-  Future<dynamic> writeFile(String fsName, Uri deviceUri, DevFSContent content);
-}
-
-/// An implementation of [DevFSOperations] that speaks to the
-/// vm service.
-class ServiceProtocolDevFSOperations implements DevFSOperations {
-  ServiceProtocolDevFSOperations(this.vmService);
+class DevFSOperations {
+  DevFSOperations(this.vmService, this.fsName)
+      : httpAddress = vmService.httpAddress;
 
   final VMService vmService;
-
-  @override
-  Future<Uri> create(String fsName) async {
-    final Map<String, dynamic> response = await vmService.vm.createDevFS(fsName);
-    return Uri.parse(response['uri']);
-  }
-
-  @override
-  Future<dynamic> destroy(String fsName) async {
-    await vmService.vm.deleteDevFS(fsName);
-  }
-
-  @override
-  Future<dynamic> writeFile(String fsName, Uri deviceUri, DevFSContent content) async {
-    List<int> bytes;
-    try {
-      bytes = await content.contentsAsBytes();
-    } catch (e) {
-      return e;
-    }
-    final String fileContents = base64.encode(bytes);
-    try {
-      return await vmService.vm.invokeRpcRaw(
-        '_writeDevFSFile',
-        params: <String, dynamic>{
-          'fsName': fsName,
-          'uri': deviceUri.toString(),
-          'fileContents': fileContents,
-        },
-      );
-    } catch (error) {
-      printTrace('DevFS: Failed to write $deviceUri: $error');
-    }
-  }
-}
-
-class DevFSException implements Exception {
-  DevFSException(this.message, [this.error, this.stackTrace]);
-  final String message;
-  final dynamic error;
-  final StackTrace stackTrace;
-}
-
-class _DevFSHttpWriter {
-  _DevFSHttpWriter(this.fsName, VMService serviceProtocol)
-    : httpAddress = serviceProtocol.httpAddress;
-
   final String fsName;
   final Uri httpAddress;
+  final HttpClient _client = HttpClient();
 
   static const int kMaxInFlight = 6;
 
   int _inFlight = 0;
   Map<Uri, DevFSContent> _outstanding;
   Completer<void> _completer;
-  final HttpClient _client = HttpClient();
+
+  Future<Uri> create(String fsName) async {
+    final Map<String, dynamic> response = await vmService.vm.createDevFS(fsName);
+    return Uri.parse(response['uri']);
+  }
+
+  Future<void> destroy(String fsName) async {
+    await vmService.vm.deleteDevFS(fsName);
+  }
 
   Future<void> write(Map<Uri, DevFSContent> entries) async {
     _client.maxConnectionsPerHost = kMaxInFlight;
@@ -301,9 +259,9 @@ class _DevFSHttpWriter {
       final HttpClientRequest request = await _client.putUrl(httpAddress);
       request.headers.removeAll(HttpHeaders.acceptEncodingHeader);
       request.headers.add('dev_fs_name', fsName);
-      request.headers.add('dev_fs_uri_b64', base64.encode(utf8.encode('$deviceUri')));
-      final Stream<List<int>> contents = content.contentsAsCompressedStream();
-      await request.addStream(contents);
+      request.headers.add('dev_fs_uri_b64',
+          base64.encode(utf8.encode(deviceUri.toString())));
+      request.add(content.contentsAsCompressedBytes());
       final HttpClientResponse response = await request.close();
       await response.drain<void>();
     } catch (error, trace) {
@@ -317,6 +275,14 @@ class _DevFSHttpWriter {
   }
 }
 
+class DevFSException implements Exception {
+  DevFSException(this.message, [this.error, this.stackTrace]);
+
+  final String message;
+  final dynamic error;
+  final StackTrace stackTrace;
+}
+
 // Basic statistics for DevFS update operation.
 class UpdateFSReport {
   UpdateFSReport({
@@ -353,8 +319,7 @@ class DevFS {
     this.fsName,
     this.rootDirectory, {
     String packagesFilePath,
-  }) : _operations = ServiceProtocolDevFSOperations(serviceProtocol),
-       _httpWriter = _DevFSHttpWriter(fsName, serviceProtocol),
+  }) : _operations = DevFSOperations(serviceProtocol, fsName),
        _packagesFilePath = packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
 
   DevFS.operations(
@@ -362,11 +327,9 @@ class DevFS {
     this.fsName,
     this.rootDirectory, {
     String packagesFilePath,
-  }) : _httpWriter = null,
-       _packagesFilePath = packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
+  }) : _packagesFilePath = packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
 
   final DevFSOperations _operations;
-  final _DevFSHttpWriter _httpWriter;
   final String fsName;
   final Directory rootDirectory;
   String _packagesFilePath;
@@ -489,7 +452,7 @@ class DevFS {
     printTrace('Updating files');
     if (dirtyEntries.isNotEmpty) {
       try {
-        await _httpWriter.write(dirtyEntries);
+        await _operations.write(dirtyEntries);
       } on SocketException catch (socketException, stackTrace) {
         printTrace('DevFS sync failed. Lost connection to device: $socketException');
         throw DevFSException('Lost connection to device.', socketException, stackTrace);

packages/flutter_tools/lib/src/fuchsia/fuchsia_build.dart

@@ -52,7 +52,7 @@ Future<void> _buildAssets(
 
   final Map<String, DevFSContent> assetEntries =
       Map<String, DevFSContent>.from(assets.entries);
-  await writeBundle(fs.directory(assetDir), assetEntries);
+  writeBundle(fs.directory(assetDir), assetEntries);
 
   final String appName = fuchsiaProject.project.manifest.appName;
   final String outDir = getFuchsiaBuildDirectory();

packages/flutter_tools/lib/src/resident_web_runner.dart

@@ -120,8 +120,7 @@ class ResidentWebRunner extends ResidentRunner {
     if (build != 0) {
       throwToolExit('Error: Failed to build asset bundle');
     }
-    await writeBundle(
-        fs.directory(getAssetBuildDirectory()), assetBundle.entries);
+    writeBundle(fs.directory(getAssetBuildDirectory()), assetBundle.entries);
 
     // Step 2: Start an HTTP server
     _server = WebAssetServer(flutterProject, target, ipv6);

packages/flutter_tools/lib/src/web/web_device.dart

@@ -119,7 +119,7 @@ class WebDevice extends Device {
     if (build != 0) {
       throwToolExit('Error: Failed to build asset bundle');
     }
-    await writeBundle(fs.directory(getAssetBuildDirectory()), assetBundle.entries);
+    writeBundle(fs.directory(getAssetBuildDirectory()), assetBundle.entries);
 
     _package = package;
     _server = await HttpServer.bind(InternetAddress.loopbackIPv4, 0);

packages/flutter_tools/test/asset_bundle_package_fonts_test.dart

@@ -74,7 +74,7 @@ $fontsSection
         final String entryKey = 'packages/$packageName/$packageFont';
         expect(bundle.entries.containsKey(entryKey), true);
         expect(
-          utf8.decode(await bundle.entries[entryKey].contentsAsBytes()),
+          utf8.decode(bundle.entries[entryKey].contentsAsBytes()),
           packageFont,
         );
       }
@@ -82,14 +82,14 @@ $fontsSection
       for (String localFont in localFonts) {
         expect(bundle.entries.containsKey(localFont), true);
         expect(
-          utf8.decode(await bundle.entries[localFont].contentsAsBytes()),
+          utf8.decode(bundle.entries[localFont].contentsAsBytes()),
           localFont,
         );
       }
     }
 
     expect(
-      json.decode(utf8.decode(await bundle.entries['FontManifest.json'].contentsAsBytes())),
+      json.decode(utf8.decode(bundle.entries['FontManifest.json'].contentsAsBytes())),
       json.decode(expectedAssetManifest),
     );
   }

packages/flutter_tools/test/asset_bundle_package_test.dart

@@ -79,14 +79,14 @@ $assetsSection
         final String entryKey = Uri.encodeFull('packages/$packageName/$asset');
         expect(bundle.entries.containsKey(entryKey), true, reason: 'Cannot find key on bundle: $entryKey');
         expect(
-          utf8.decode(await bundle.entries[entryKey].contentsAsBytes()),
+          utf8.decode(bundle.entries[entryKey].contentsAsBytes()),
           asset,
         );
       }
     }
 
     expect(
-      utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+      utf8.decode(bundle.entries['AssetManifest.json'].contentsAsBytes()),
       expectedAssetManifest,
     );
   }
@@ -126,11 +126,11 @@ $assetsSection
       expect(bundle.entries.length, 3); // LICENSE, AssetManifest, FontManifest
       const String expectedAssetManifest = '{}';
       expect(
-        utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+        utf8.decode(bundle.entries['AssetManifest.json'].contentsAsBytes()),
         expectedAssetManifest,
       );
       expect(
-        utf8.decode(await bundle.entries['FontManifest.json'].contentsAsBytes()),
+        utf8.decode(bundle.entries['FontManifest.json'].contentsAsBytes()),
         '[]',
       );
     }, overrides: <Type, Generator>{
@@ -153,11 +153,11 @@ $assetsSection
       expect(bundle.entries.length, 3); // LICENSE, AssetManifest, FontManifest
       const String expectedAssetManifest = '{}';
       expect(
-        utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+        utf8.decode(bundle.entries['AssetManifest.json'].contentsAsBytes()),
         expectedAssetManifest,
       );
       expect(
-        utf8.decode(await bundle.entries['FontManifest.json'].contentsAsBytes()),
+        utf8.decode(bundle.entries['FontManifest.json'].contentsAsBytes()),
         '[]',
       );
     }, overrides: <Type, Generator>{

packages/flutter_tools/test/asset_bundle_test.dart

@@ -50,7 +50,7 @@ void main() {
       expect(bundle.entries.length, 1);
       const String expectedAssetManifest = '{}';
       expect(
-        utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+        utf8.decode(bundle.entries['AssetManifest.json'].contentsAsBytes()),
         expectedAssetManifest,
       );
     }, overrides: <Type, Generator>{

packages/flutter_tools/test/asset_bundle_variant_test.dart

@@ -76,7 +76,7 @@ flutter:
       // The main asset file, /a/b/c/foo, and its variants exist.
       for (String asset in assets) {
         expect(bundle.entries.containsKey(asset), true);
-        expect(utf8.decode(await bundle.entries[asset].contentsAsBytes()), asset);
+        expect(utf8.decode(bundle.entries[asset].contentsAsBytes()), asset);
       }
 
       fs.file(fixPath('a/b/c/foo')).deleteSync();
@@ -88,7 +88,7 @@ flutter:
       expect(bundle.entries.containsKey('a/b/c/foo'), false);
       for (String asset in assets.skip(1)) {
         expect(bundle.entries.containsKey(asset), true);
-        expect(utf8.decode(await bundle.entries[asset].contentsAsBytes()), asset);
+        expect(utf8.decode(bundle.entries[asset].contentsAsBytes()), asset);
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,

packages/flutter_tools/test/asset_test.dart

@@ -7,6 +7,7 @@ import 'dart:async';
 import 'package:flutter_tools/src/asset.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/convert.dart';
 
 import 'src/common.dart';
 import 'src/context.dart';
@@ -65,5 +66,5 @@ void main() {
 }
 
 Future<String> getValueAsString(String key, AssetBundle asset) async {
-  return String.fromCharCodes(await asset.entries[key].contentsAsBytes());
+  return utf8.decode(asset.entries[key].contentsAsBytes());
 }

packages/flutter_tools/test/devfs_test.dart

@@ -4,15 +4,17 @@
 
 import 'dart:async';
 import 'dart:convert';
-import 'dart:io'; // ignore: dart_io_import
 
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
+import 'package:flutter_tools/src/base/context.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
+import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/devfs.dart';
 import 'package:flutter_tools/src/vmservice.dart';
 import 'package:json_rpc_2/json_rpc_2.dart' as rpc;
+import 'package:mockito/mockito.dart';
 
 import 'src/common.dart';
 import 'src/context.dart';
@@ -20,17 +22,39 @@ import 'src/mocks.dart';
 
 void main() {
   FileSystem fs;
-  String filePath;
-  Directory tempDir;
-  String basePath;
-  DevFS devFS;
+  MockPlatform mockPlatform;
 
-  setUpAll(() {
-    fs = MemoryFileSystem();
-    filePath = fs.path.join('lib', 'foo.txt');
+  setUp(() {
+    fs = MemoryFileSystem(style: FileSystemStyle.posix);
+    mockPlatform = MockPlatform();
+    when(mockPlatform.pathSeparator).thenReturn('/');
+    when(mockPlatform.isWindows).thenReturn(false);
   });
 
   group('DevFSContent', () {
+    test('copyToFile', () {
+      final String filePath = fs.path.join('lib', 'foo.txt');
+      final File file = fs.file(filePath)
+        ..createSync(recursive: true)
+        ..writeAsStringSync('hello, world');
+      final DevFSByteContent byteContent = DevFSByteContent(<int>[4, 5, 6]);
+      final DevFSStringContent stringContent = DevFSStringContent('some string');
+      final DevFSFileContent fileContent = DevFSFileContent(file);
+
+      final File byteDestination = fs.file('byte_dest');
+      final File stringDestination = fs.file('string_dest');
+      final File fileDestination = fs.file('file_dest');
+
+      byteContent.copyToFile(byteDestination);
+      expect(byteDestination.readAsBytesSync(), <int>[4, 5, 6]);
+
+      stringContent.copyToFile(stringDestination);
+      expect(stringDestination.readAsStringSync(), 'some string');
+
+      fileContent.copyToFile(fileDestination);
+      expect(fileDestination.readAsStringSync(), 'hello, world');
+    });
+
     test('bytes', () {
       final DevFSByteContent content = DevFSByteContent(<int>[4, 5, 6]);
       expect(content.bytes, orderedEquals(<int>[4, 5, 6]));
@@ -41,6 +65,7 @@ void main() {
       expect(content.isModified, isTrue);
       expect(content.isModified, isFalse);
     });
+
     test('string', () {
       final DevFSStringContent content = DevFSStringContent('some string');
       expect(content.string, 'some string');
@@ -58,7 +83,9 @@ void main() {
       expect(content.isModified, isTrue);
       expect(content.isModified, isFalse);
     });
+
     testUsingContext('file', () async {
+      final String filePath = fs.path.join('lib', 'foo.txt');
       final File file = fs.file(filePath);
       final DevFSFileContent content = DevFSFileContent(file);
       expect(content.isModified, isFalse);
@@ -73,10 +100,9 @@ void main() {
       expect(content.isModifiedAfter(null), isTrue);
 
       file.writeAsBytesSync(<int>[2, 3, 4], flush: true);
-      expect(content.fileDependencies, <String>[filePath]);
       expect(content.isModified, isTrue);
       expect(content.isModified, isFalse);
-      expect(await content.contentsAsBytes(), <int>[2, 3, 4]);
+      expect(content.contentsAsBytes(), <int>[2, 3, 4]);
       updateFileModificationTime(file.path, fiveSecondsAgo, 0);
       expect(content.isModified, isFalse);
       expect(content.isModified, isFalse);
@@ -87,36 +113,56 @@ void main() {
       expect(content.isModified, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-    }, skip: Platform.isWindows); // TODO(jonahwilliams): fix or disable this functionality.
+    }, skip: platform.isWindows); // Still flaky, but only on CI :(
   });
 
   group('devfs remote', () {
-    MockVMService vmService;
-    final MockResidentCompiler residentCompiler = MockResidentCompiler();
-
-    setUpAll(() async {
-      tempDir = _newTempDir(fs);
-      basePath = tempDir.path;
-      vmService = MockVMService();
-      await vmService.setUp();
+    DevFS devFS;
+    MockResidentCompiler residentCompiler;
+    MockDevFSOperations mockDevFSOperations;
+    int created;
+    int destroyed;
+    List<String> writtenFiles;
+    bool exists;
+
+    setUp(() async {
+      mockDevFSOperations = MockDevFSOperations();
+      devFS = DevFS.operations(mockDevFSOperations, 'test', fs.currentDirectory);
+      residentCompiler = MockResidentCompiler();
+      created = 0;
+      destroyed = 0;
+      exists = false;
+      writtenFiles = <String>[];
+      when(mockDevFSOperations.create('test')).thenAnswer((Invocation invocation) async {
+        if (exists) {
+          throw rpc.RpcException(1001, 'already exists');
+        }
+        exists = true;
+        created += 1;
+        return Uri.parse(InternetAddress.loopbackIPv4.toString());
+      });
+      when(mockDevFSOperations.destroy('test')).thenAnswer((Invocation invocation) async {
+        exists = false;
+        destroyed += 1;
+      });
+      when(mockDevFSOperations.write(any)).thenAnswer((Invocation invocation) async {
+        final Map<Uri, DevFSContent> entries = invocation.positionalArguments.first;
+        writtenFiles.addAll(entries.keys.map((Uri uri) => uri.toFilePath()));
       });
-    tearDownAll(() async {
-      await vmService.tearDown();
-      _cleanupTempDirs();
     });
 
     testUsingContext('create dev file system', () async {
       // simulate workspace
-      final File file = fs.file(fs.path.join(basePath, filePath));
+      final String filePath = fs.path.join('lib', 'foo.txt');
+      final File file = fs.file(filePath);
       await file.parent.create(recursive: true);
       file.writeAsBytesSync(<int>[1, 2, 3]);
 
       // simulate package
       await _createPackage(fs, 'somepkg', 'somefile.txt');
-
-      devFS = DevFS(vmService, 'test', tempDir);
       await devFS.create();
-      vmService.expectMessages(<String>['create test']);
+
+      expect(created, 1);
       expect(devFS.assetPathsToEvict, isEmpty);
 
       final UpdateFSReport report = await devFS.update(
@@ -126,9 +172,8 @@ void main() {
         trackWidgetCreation: false,
         invalidatedFiles: <Uri>[],
       );
-      vmService.expectMessages(<String>[
-        'writeFile test lib/foo.txt.dill',
-      ]);
+
+      expect(writtenFiles.single, contains('foo.txt.dill'));
       expect(devFS.assetPathsToEvict, isEmpty);
       expect(report.syncedBytes, 22);
       expect(report.success, true);
@@ -137,9 +182,8 @@ void main() {
     });
 
     testUsingContext('delete dev file system', () async {
-      expect(vmService.messages, isEmpty, reason: 'prior test timeout');
       await devFS.destroy();
-      vmService.expectMessages(<String>['destroy test']);
+      expect(destroyed, 1);
       expect(devFS.assetPathsToEvict, isEmpty);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
@@ -147,26 +191,27 @@ void main() {
 
     testUsingContext('cleanup preexisting file system', () async {
       // simulate workspace
-      final File file = fs.file(fs.path.join(basePath, filePath));
+      final String filePath = fs.path.join('lib', 'foo.txt');
+      final File file = fs.file(filePath);
       await file.parent.create(recursive: true);
       file.writeAsBytesSync(<int>[1, 2, 3]);
 
       // simulate package
       await _createPackage(fs, 'somepkg', 'somefile.txt');
 
-      devFS = DevFS(vmService, 'test', tempDir);
       await devFS.create();
-      vmService.expectMessages(<String>['create test']);
+      expect(created, 1);
       expect(devFS.assetPathsToEvict, isEmpty);
 
       // Try to create again.
       await devFS.create();
-      vmService.expectMessages(<String>['create test', 'destroy test', 'create test']);
+      expect(created, 2);
+      expect(destroyed, 1);
       expect(devFS.assetPathsToEvict, isEmpty);
 
       // Really destroy.
       await devFS.destroy();
-      vmService.expectMessages(<String>['destroy test']);
+      expect(destroyed, 2);
       expect(devFS.assetPathsToEvict, isEmpty);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
@@ -174,113 +219,20 @@ void main() {
   });
 }
 
-class MockVMService extends BasicMock implements VMService {
-  MockVMService() {
-    _vm = MockVM(this);
-  }
-
-  Uri _httpAddress;
-  HttpServer _server;
-  MockVM _vm;
-
-  @override
-  Uri get httpAddress => _httpAddress;
-
-  @override
-  VM get vm => _vm;
-
-  Future<void> setUp() async {
-    try {
-      _server = await HttpServer.bind(InternetAddress.loopbackIPv6, 0);
-      _httpAddress = Uri.parse('http://[::1]:${_server.port}');
-    } on SocketException {
-      // Fall back to IPv4 if the host doesn't support binding to IPv6 localhost
-      _server = await HttpServer.bind(InternetAddress.loopbackIPv4, 0);
-      _httpAddress = Uri.parse('http://127.0.0.1:${_server.port}');
-    }
-    _server.listen((HttpRequest request) {
-      final String fsName = request.headers.value('dev_fs_name');
-      final String devicePath = utf8.decode(base64.decode(request.headers.value('dev_fs_uri_b64')));
-      messages.add('writeFile $fsName $devicePath');
-      request.drain<List<int>>().then<void>((List<int> value) {
-        request.response
-          ..write('Got it')
-          ..close();
-      });
-    });
-  }
-
-  Future<void> tearDown() async {
-    await _server?.close();
-  }
-
-  @override
-  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
-}
-
-class MockVM implements VM {
-  MockVM(this._service);
+class MockVMService extends Mock implements VMService {}
 
-  final MockVMService _service;
-  final Uri _baseUri = Uri.parse('file:///tmp/devfs/test');
-  bool _devFSExists = false;
+class MockDevFSOperations extends Mock implements DevFSOperations {}
 
-  static const int kFileSystemAlreadyExists = 1001;
+class MockPlatform extends Mock implements Platform {}
 
-  @override
-  Future<Map<String, dynamic>> createDevFS(String fsName) async {
-    _service.messages.add('create $fsName');
-    if (_devFSExists) {
-      throw rpc.RpcException(kFileSystemAlreadyExists, 'File system already exists');
-    }
-    _devFSExists = true;
-    return <String, dynamic>{'uri': '$_baseUri'};
-  }
-
-  @override
-  Future<Map<String, dynamic>> deleteDevFS(String fsName) async {
-    _service.messages.add('destroy $fsName');
-    _devFSExists = false;
-    return <String, dynamic>{'type': 'Success'};
-  }
-
-  @override
-  Future<Map<String, dynamic>> invokeRpcRaw(
-    String method, {
-    Map<String, dynamic> params = const <String, dynamic>{},
-    Duration timeout,
-    bool timeoutFatal = true,
-  }) async {
-    _service.messages.add('$method $params');
-    return <String, dynamic>{'success': true};
-  }
-
-  @override
-  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
-}
-
-
-final List<Directory> _tempDirs = <Directory>[];
 final Map <String, Uri> _packages = <String, Uri>{};
 
-Directory _newTempDir(FileSystem fs) {
-  final Directory tempDir = fs.systemTempDirectory.createTempSync('flutter_devfs${_tempDirs.length}_test.');
-  _tempDirs.add(tempDir);
-  return tempDir;
-}
-
-void _cleanupTempDirs() {
-  while (_tempDirs.isNotEmpty)
-    tryToDelete(_tempDirs.removeLast());
-}
 
 Future<void> _createPackage(FileSystem fs, String pkgName, String pkgFileName, { bool doubleSlash = false }) async {
-  final Directory pkgTempDir = _newTempDir(fs);
-  String pkgFilePath = fs.path.join(pkgTempDir.path, pkgName, 'lib', pkgFileName);
+  String pkgFilePath = fs.path.join(pkgName, 'lib', pkgFileName);
   if (doubleSlash) {
     // Force two separators into the path.
-    final String doubleSlash = fs.path.separator + fs.path.separator;
-    pkgFilePath = pkgTempDir.path + doubleSlash + fs.path.join(pkgName, 'lib', pkgFileName);
+    pkgFilePath = fs.path.join(pkgName, 'lib', pkgFileName);
   }
   final File pkgFile = fs.file(pkgFilePath);
   await pkgFile.parent.create(recursive: true);
@@ -290,6 +242,5 @@ Future<void> _createPackage(FileSystem fs, String pkgName, String pkgFileName, {
   _packages.forEach((String pkgName, Uri pkgUri) {
     sb.writeln('$pkgName:$pkgUri');
   });
-  fs.file(fs.path.join(_tempDirs[0].path, '.packages')).writeAsStringSync(sb.toString());
+  fs.file('.packages').writeAsStringSync(sb.toString());
 }
-

packages/flutter_tools/test/src/mocks.dart

@@ -14,7 +14,6 @@ import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/compile.dart';
-import 'package:flutter_tools/src/devfs.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/ios/devices.dart';
 import 'package:flutter_tools/src/ios/simulators.dart';
@@ -478,30 +477,6 @@ class BasicMock {
   }
 }
 
-class MockDevFSOperations extends BasicMock implements DevFSOperations {
-  Map<Uri, DevFSContent> devicePathToContent = <Uri, DevFSContent>{};
-
-  @override
-  Future<Uri> create(String fsName) async {
-    messages.add('create $fsName');
-    return Uri.parse('file:///$fsName');
-  }
-
-  @override
-  Future<dynamic> destroy(String fsName) async {
-    messages.add('destroy $fsName');
-  }
-
-  @override
-  Future<dynamic> writeFile(String fsName, Uri deviceUri, DevFSContent content) async {
-    String message = 'writeFile $fsName $deviceUri';
-    if (content is DevFSFileContent) {
-      message += ' ${content.file.path}';
-    }
-    messages.add(message);
-    devicePathToContent[deviceUri] = content;
-  }
-}
 
 class MockResidentCompiler extends BasicMock implements ResidentCompiler {
   @override