Add metadata to messages emitted by live tests.

test/backend/invoker_test.dart

 // Copyright (c) 2015, 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 'package:fake_async/fake_async.dart';
 import 'package:test/src/backend/group.dart';
 import 'package:test/src/backend/invoker.dart';
+import 'package:test/src/backend/message.dart';
 import 'package:test/src/backend/metadata.dart';
 import 'package:test/src/backend/state.dart';
 import 'package:test/src/backend/suite.dart';
 import 'package:test/test.dart';
 
 import '../utils.dart';
 
 void main() {
   var suite;
   setUp(() {
@@ skipping 353 matching lines @@
     expect(outstandingCallbackRemoved, isTrue);
   });
 
   test("a test's prints are captured and reported", () {
     expect(() {
       var liveTest = _localTest(() {
         print("Hello,");
         return new Future(() => print("world!"));
       }).load(suite);
 
-      expect(liveTest.onPrint.take(2).toList(),
-          completion(equals(["Hello,", "world!"])));
+      expect(liveTest.onMessage.take(2).toList().then((messages) {
+        expect(messages[0].type, equals(MessageType.print));
+        expect(messages[0].text, equals("Hello,"));
+        expect(messages[1].type, equals(MessageType.print));
+        expect(messages[1].text, equals("world!"));
+      }), completes);
 
       return liveTest.run();
     }, prints(isEmpty));
   });
 
   group("timeout:", () {
     test("a test times out after 30 seconds by default", () {
       new FakeAsync().run((async) {
         var liveTest = _localTest(() {
           Invoker.current.addOutstandingCallback();
@@ skipping 128 matching lines @@
       expect(liveTest.state.status, equals(Status.complete));
       expect(isComplete, isFalse);
     });
   });
 }
 
 LocalTest _localTest(body(), {Metadata metadata}) {
   if (metadata == null) metadata = new Metadata();
   return new LocalTest("test", metadata, body);
 }