Don't hardcode 'dart' as the executable name to spawn.

pkg/dev_compiler/test/worker/worker_test.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. 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:convert';
 import 'dart:io';
 
 import 'package:bazel_worker/bazel_worker.dart';
 // TODO(jakemac): Remove once this is a part of the testing library.
@@ skipping 26 matching lines @@
     tearDown(() {
       if (inputDartFile.existsSync()) inputDartFile.deleteSync();
       if (outputJsFile.parent.existsSync()) {
         outputJsFile.parent.deleteSync(recursive: true);
       }
       if (argsFile.existsSync()) argsFile.deleteSync();
     });
 
     test('can compile in worker mode', () async {
       var args = executableArgs.toList()..add('--persistent_worker');
-      var process = await Process.start('dart', args);
+      var process = await Process.start(Platform.executable, args);
       var messageGrouper = new AsyncMessageGrouper(process.stdout);
 
       var request = new WorkRequest();
       request.arguments.addAll(compilerArgs);
       process.stdin.add(protoToDelimitedBuffer(request));
 
       var response = await _readResponse(messageGrouper);
       expect(response.exitCode, EXIT_CODE_OK, reason: response.output);
       expect(response.output, isEmpty);
 
@@ skipping 11 matching lines @@
 
       process.kill();
 
       // TODO(jakemac): This shouldn't be necessary, but it is for the process
       // to exit properly.
       expect(await messageGrouper.next, isNull);
     });
 
     test('can compile in basic mode', () {
       var args = executableArgs.toList()..addAll(compilerArgs);
-      var result = Process.runSync('dart', args);
+      var result = Process.runSync(Platform.executable, args);
 
       expect(result.exitCode, EXIT_CODE_OK);
       expect(result.stdout, isEmpty);
       expect(result.stderr, isEmpty);
       expect(outputJsFile.existsSync(), isTrue);
     });
 
     test('unknown options', () {
       var args = new List<String>.from(executableArgs)
         ..add('--does-not-exist')
         ..addAll(compilerArgs);
-      var result = Process.runSync('dart', args);
+      var result = Process.runSync(Platform.executable, args);
 
       expect(result.exitCode, 64);
       expect(result.stdout,
           contains('Could not find an option named "does-not-exist"'));
       expect(result.stderr, isEmpty);
       expect(outputJsFile.existsSync(), isFalse);
     });
 
     test('unknown options ignored', () {
       var args = new List<String>.from(executableArgs)
         ..add('--does-not-exist')
         ..add('--ignore-unrecognized-flags')
         ..addAll(compilerArgs);
-      var result = Process.runSync('dart', args);
+      var result = Process.runSync(Platform.executable, args);
 
       expect(result.exitCode, EXIT_CODE_OK);
       expect(result.stdout, isEmpty);
       expect(result.stderr, isEmpty);
       expect(outputJsFile.existsSync(), isTrue);
     });
 
     test('can compile in basic mode with args in a file', () async {
       argsFile.createSync();
       argsFile.writeAsStringSync(compilerArgs.join('\n'));
       var args = executableArgs.toList()..add('@${argsFile.path}');
-      var process = await Process.start('dart', args);
+      var process = await Process.start(Platform.executable, args);
       stderr.addStream(process.stderr);
       var futureProcessOutput = process.stdout.map(UTF8.decode).toList();
 
       expect(await process.exitCode, EXIT_CODE_OK);
       expect((await futureProcessOutput).join(), isEmpty);
       expect(outputJsFile.existsSync(), isTrue);
     });
   });
 
   group('Hello World with Summaries', () {
@@ skipping 13 matching lines @@
     tearDown(() {
       if (greetingDart.existsSync()) greetingDart.deleteSync();
       if (helloDart.existsSync()) helloDart.deleteSync();
       if (greetingJS.existsSync()) greetingJS.deleteSync();
       if (greetingSummary.existsSync()) greetingSummary.deleteSync();
       if (helloJS.existsSync()) helloJS.deleteSync();
     });
 
     test('can compile in basic mode', () {
       final dartSdkSummary = new File('lib/sdk/ddc_sdk.sum').absolute;
-      var result = Process.runSync('dart', [
+      var result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--summary-extension=api.ds',
         '--no-source-map',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         '-o',
         greetingJS.path,
         greetingDart.path,
       ]);
       expect(result.exitCode, EXIT_CODE_OK);
       expect(result.stdout, isEmpty);
       expect(result.stderr, isEmpty);
       expect(greetingJS.existsSync(), isTrue);
       expect(greetingSummary.existsSync(), isTrue);
 
-      result = Process.runSync('dart', [
+      result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--no-source-map',
         '--no-summarize',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         '--summary-extension=api.ds',
         '-s',
         greetingSummary.path,
         '-o',
         helloJS.path,
@@ skipping 10 matching lines @@
     final dartSdkSummary = new File('lib/sdk/ddc_sdk.sum').absolute;
     final badFileDart = new File('test/worker/bad.dart').absolute;
     final badFileJs = new File('test/worker/bad.js').absolute;
 
     tearDown(() {
       if (badFileDart.existsSync()) badFileDart.deleteSync();
       if (badFileJs.existsSync()) badFileJs.deleteSync();
     });
 
     test('incorrect usage', () {
-      var result = Process.runSync('dart', [
+      var result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         'oops',
       ]);
       expect(result.exitCode, 64);
       expect(
           result.stdout, contains('Please include the output file location.'));
       expect(result.stdout, isNot(contains('#0')));
     });
 
     test('compile errors', () {
       badFileDart.writeAsStringSync('main() => "hello world"');
-      var result = Process.runSync('dart', [
+      var result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--no-source-map',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         '-o',
         badFileJs.path,
         badFileDart.path,
       ]);
       expect(result.exitCode, 1);
       expect(result.stdout, contains("[error] Expected to find ';'"));
@@ skipping 15 matching lines @@
           'main() => print(greeting);\n');
     });
 
     tearDown(() {
       if (partFile.existsSync()) partFile.deleteSync();
       if (libraryFile.existsSync()) libraryFile.deleteSync();
       if (outJS.existsSync()) outJS.deleteSync();
     });
 
     test('works if part and library supplied', () {
-      var result = Process.runSync('dart', [
+      var result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--no-summarize',
         '--no-source-map',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         '-o',
         outJS.path,
         partFile.path,
         libraryFile.path,
       ]);
       expect(result.stdout, isEmpty);
       expect(result.stderr, isEmpty);
       expect(result.exitCode, 0);
       expect(outJS.existsSync(), isTrue);
     });
 
     test('works if part is not supplied', () {
-      var result = Process.runSync('dart', [
+      var result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--no-summarize',
         '--no-source-map',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         '-o',
         outJS.path,
         libraryFile.path,
       ]);
       expect(result.stdout, isEmpty);
       expect(result.stderr, isEmpty);
       expect(result.exitCode, 0);
       expect(outJS.existsSync(), isTrue);
     });
 
     test('part without library is silently ignored', () {
-      var result = Process.runSync('dart', [
+      var result = Process.runSync(Platform.executable, [
         'bin/dartdevc.dart',
         '--no-summarize',
         '--no-source-map',
         '--dart-sdk-summary',
         dartSdkSummary.path,
         '-o',
         outJS.path,
         partFile.path,
       ]);
       expect(result.stdout, isEmpty);
       expect(result.stderr, isEmpty);
       expect(result.exitCode, 0);
       expect(outJS.existsSync(), isTrue);
     });
   });
 }
 
 Future<WorkResponse> _readResponse(MessageGrouper messageGrouper) async {
   var buffer = (await messageGrouper.next) as List<int>;
   try {
     return new WorkResponse.fromBuffer(buffer);
   } catch (_) {
     var bufferAsString =
         buffer == null ? '' : 'String: ${UTF8.decode(buffer)}\n';
     throw 'Failed to parse response:\nbytes: $buffer\n$bufferAsString';
   }
 }