Added async_helper and fixed broken asynchronous test.

pkg/intl/test/intl_message_basic_example_test.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Tests internationalization of messages using the basic example as a template.
  */
 library intl_message_test_2;
 
 import 'package:intl/intl.dart';
 import '../example/basic/basic_example.dart';
 import 'package:unittest/unittest.dart';
 import 'dart:async';
 
-List list;
+main() {
+  var list = [];
+  var waitForIt = new Completer();
 
-main() {
-  list = [];
-  setup(runAllTests, addToList);
+  addToList(x) {
+    list.add(x);
+    if (list.length == 4) {
+      waitForIt.complete(list);
+    }
+  }
+
+  test('Verify basic example printing localized messages', () {
+    runAllTests(_) {
+      setup(expectAsync1(runProgram), addToList);
+    }
+    setup(expectAsync1(runAllTests), addToList);
+    waitForIt.future.then(expectAsync1((_) {
+      expect(list[0], "Ran at 00:00:00 on Thursday, January 1, 1970");
+      expect(list[1], "Ausgedruckt am 00:00:00 am Donnerstag, 1. Januar 1970.");
+      expect(list[2], "วิ่ง 0:00:00 on วันพฤหัสบดี 1 มกราคม 1970.");
+      expect(list[3], "วิ่ง now on today.");
+    }));
+  });
 }
 
-var waitForIt = new Completer();
-
-addToList(x) {
-  list.add(x);
-  if (list.length == 4) waitForIt.complete(list);
-}
-
-runAllTests(_) {
-  setup(runProgram, addToList);
-  waitForIt.future.then(actuallyRunTheTests);
-}
-
-actuallyRunTheTests(_) {
-  test('Verify basic example printing localized messages', () {
-    expect(list[0], "Ran at 00:00:00 on Thursday, January 1, 1970");
-    expect(list[1], "Ausgedruckt am 00:00:00 am Donnerstag, 1. Januar 1970.");
-    expect(list[2], "วิ่ง 0:00:00 on วันพฤหัสบดี 1 มกราคม 1970.");
-    expect(list[3], "วิ่ง now on today.");
-  });
-}