Add a command for running unit tests

packages/flutter_tools/lib/executable.dart

@@ -21,6 +21,7 @@ import 'src/commands/logs.dart';
 import 'src/commands/run_mojo.dart';
 import 'src/commands/start.dart';
 import 'src/commands/stop.dart';
+import 'src/commands/test.dart';
 import 'src/commands/trace.dart';
 import 'src/process.dart';
 
@@ -54,6 +55,7 @@ Future main(List<String> args) async {
     ..addCommand(new RunMojoCommand())
     ..addCommand(new StartCommand())
     ..addCommand(new StopCommand())
+    ..addCommand(new TestCommand())
     ..addCommand(new TraceCommand());
 
   return Chain.capture(() async {

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

@@ -0,0 +1,44 @@
+// Copyright 2015 The Chromium 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 'dart:async';
+import 'dart:io';
+
+import 'package:logging/logging.dart';
+import 'package:path/path.dart' as path;
+import 'package:test/src/executable.dart' as executable;
+
+import 'flutter_command.dart';
+import '../test/loader.dart' as loader;
+
+final Logger _logging = new Logger('sky_tools.test');
+
+class TestCommand extends FlutterCommand {
+  final String name = 'test';
+  final String description = 'Runs Flutter unit tests for the current project (requires a local build of the engine).';
+
+  TestCommand() {
+    argParser.addOption('build-dir', defaultsTo: '../../../engine/src/out/Debug');
+  }
+
+  String get _shellPath {
+    if (Platform.isLinux)
+      return path.join(argResults['build-dir'], 'sky_shell');
+    if (Platform.isMacOS)
+      return path.join(argResults['build-dir'], 'SkyShell.app', 'Contents', 'MacOS', 'SkyShell');
+    throw new Exception('Unsupported platform.');
+  }
+
+  @override
+  Future<int> runInProject() async {
+    loader.shellPath = _shellPath;
+    if (!FileSystemEntity.isFileSync(loader.shellPath)) {
+      _logging.severe('Cannot find Flutter Shell at ${loader.shellPath}');
+      return 1;
+    }
+    loader.installHook();
+    await executable.main(argResults.rest);
+    return exitCode;
+  }
+}

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

@@ -29,8 +29,10 @@ final String _kSkyShell = Platform.environment['SKY_SHELL'];
 const String _kHost = '127.0.0.1';
 const String _kPath = '/runner';
 
+String shellPath;
+
 // Right now a bunch of our tests crash or assert after the tests have finished running.
-// Mostly this is just because the test puts the framework in an inconsistent state with 
+// Mostly this is just because the test puts the framework in an inconsistent state with
 // a scheduled microtask that verifies that state. Eventually we should fix all these
 // problems but for now we'll just paper over them.
 const bool kExpectAllTestsToCloseCleanly = false;
@@ -54,8 +56,8 @@ Future<_ServerInfo> _createServer() async {
 }
 
 Future<Process> _startProcess(String path, { String packageRoot }) {
-  assert(_kSkyShell != null); // Please provide the path to the shell in the SKY_SHELL environment variable.
-  return Process.start(_kSkyShell, [
+  assert(shellPath != null || _kSkyShell != null); // Please provide the path to the shell in the SKY_SHELL environment variable.
+  return Process.start(shellPath ?? _kSkyShell, [
     '--enable-checked-mode',
     '--non-interactive',
     '--package-root=$packageRoot',
@@ -172,7 +174,7 @@ void main() {
       completer.complete(response["tests"].map((test) {
         var testMetadata = new Metadata.deserialize(test['metadata']);
         return new RemoteTest(test['name'], testMetadata, socket, test['index']);
-      }));        
+      }));
     }
   });