Added a simple test runner for Fuchsia. (#9461)

packages/flutter_tools/BUILD.gn

diff --git a/packages/flutter_tools/BUILD.gn b/packages/flutter_tools/BUILD.gn
index d283102..7a1a87f 100644
--- a/packages/flutter_tools/BUILD.gn
+++ b/packages/flutter_tools/BUILD.gn
@@ -2,15 +2,14 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/dart/dart_package.gni")
 import("//build/dart/dart_tool.gni")
 
-dart_tool("flutter_tools") {
+dart_package("flutter_tools") {
   package_name = "flutter_tools"
 
   source_dir = "lib"
 
-  main_dart = "bin/fuchsia_builder.dart"
-
   deps = [
     "//dart/pkg/analyzer",
     "//dart/third_party/pkg/linter",
@@ -39,3 +38,23 @@
     "//third_party/dart-pkg/pub/yaml",
   ]
 }
+
+dart_tool("fuchsia_builder") {
+  main_dart = "bin/fuchsia_builder.dart"
+
+  deps = [
+    ":flutter_tools",
+  ]
+}
+
+dart_tool("fuchsia_tester") {
+  main_dart = "bin/fuchsia_tester.dart"
+
+  deps = [
+    ":flutter_tools",
+  ]
+
+  non_dart_deps = [
+    "//flutter/shell",
+  ]
+}

packages/flutter_tools/bin/fuchsia_tester.dart

diff --git a/packages/flutter_tools/bin/fuchsia_tester.dart b/packages/flutter_tools/bin/fuchsia_tester.dart
new file mode 100644
index 0000000..42577a9
--- /dev/null
+++ b/packages/flutter_tools/bin/fuchsia_tester.dart
@@ -0,0 +1,104 @@
+// 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 'package:args/args.dart';
+import 'package:process/process.dart';
+import 'package:test/src/executable.dart'
+    as test; // ignore: implementation_imports
+
+import '../lib/src/base/common.dart';
+import '../lib/src/base/config.dart';
+import '../lib/src/base/context.dart';
+import '../lib/src/base/file_system.dart';
+import '../lib/src/base/io.dart';
+import '../lib/src/base/logger.dart';
+import '../lib/src/base/os.dart';
+import '../lib/src/base/platform.dart';
+import '../lib/src/cache.dart';
+import '../lib/src/dart/package_map.dart';
+import '../lib/src/globals.dart';
+import '../lib/src/test/flutter_platform.dart' as loader;
+import '../lib/src/usage.dart';
+
+// Note: this was largely inspired by lib/src/commands/test.dart.
+
+const String _kOptionPackages = "packages";
+const String _kOptionShell = "shell";
+const String _kOptionTestDirectory = "test-directory";
+const String _kOptionFlutterRoot = "flutter-root";
+const List<String> _kRequiredOptions = const <String>[
+  _kOptionPackages,
+  _kOptionShell,
+  _kOptionTestDirectory,
+  _kOptionFlutterRoot,
+];
+
+Future<Null> main(List<String> args) async {
+  final AppContext executableContext = new AppContext();
+  executableContext.setVariable(Logger, new StdoutLogger());
+  executableContext.runInZone(() {
+    // Initialize the context with some defaults.
+    context.putIfAbsent(Platform, () => const LocalPlatform());
+    context.putIfAbsent(FileSystem, () => const LocalFileSystem());
+    context.putIfAbsent(ProcessManager, () => const LocalProcessManager());
+    context.putIfAbsent(Logger, () => new StdoutLogger());
+    context.putIfAbsent(Cache, () => new Cache());
+    context.putIfAbsent(Config, () => new Config());
+    context.putIfAbsent(OperatingSystemUtils, () => new OperatingSystemUtils());
+    context.putIfAbsent(Usage, () => new Usage());
+    return run(args);
+  });
+}
+
+Iterable<String> _findTests(Directory directory) {
+  return directory
+      .listSync(recursive: true, followLinks: false)
+      .where((FileSystemEntity entity) =>
+          entity.path.endsWith('_test.dart') && fs.isFileSync(entity.path))
+      .map((FileSystemEntity entity) => fs.path.absolute(entity.path));
+}
+
+Future<Null> run(List<String> args) async {
+  final ArgParser parser = new ArgParser()
+    ..addOption(_kOptionPackages, help: 'The .packages file')
+    ..addOption(_kOptionShell, help: 'The Flutter shell binary')
+    ..addOption(_kOptionTestDirectory, help: 'Directory containing the tests')
+    ..addOption(_kOptionFlutterRoot, help: 'Flutter root');
+  final ArgResults argResults = parser.parse(args);
+  if (_kRequiredOptions
+      .any((String option) => !argResults.options.contains(option))) {
+    printError('Missing option! All options must be specified.');
+    exit(1);
+  }
+  // TODO(pylaligand): use a temp directory instead.
+  Cache.flutterRoot = argResults[_kOptionFlutterRoot];
+  final Directory testDirectory =
+      fs.directory(argResults[_kOptionTestDirectory]);
+  final Iterable<String> tests = _findTests(testDirectory);
+
+  final List<String> testArgs = <String>[];
+  testArgs.add('--');
+  testArgs.addAll(tests);
+
+  final String shellPath = argResults[_kOptionShell];
+  if (!fs.isFileSync(shellPath)) {
+    throwToolExit('Cannot find Flutter shell at $shellPath');
+  }
+  loader.installHook(
+    shellPath: shellPath,
+    debuggerMode: false,
+  );
+
+  PackageMap.globalPackagesPath =
+      fs.path.normalize(fs.path.absolute(argResults[_kOptionPackages]));
+  fs.currentDirectory = testDirectory;
+
+  await test.main(testArgs);
+
+  if (exitCode != 0) {
+    exit(exitCode);
+  }
+}