Add a LiveSuite class.

test/runner/json_reporter_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.
 
 @TestOn("vm")
 
 import 'dart:convert';
 
 import 'package:scheduled_test/descriptor.dart' as d;
 import 'package:scheduled_test/scheduled_stream.dart';
@@ skipping 395 matching lines @@
 
   d.file("test.dart", dart).create();
 
   var test = runTest(["test.dart"], reporter: "json");
   test.shouldExit();
 
   schedule(() async {
     var stdoutLines = await test.stdoutStream().toList();
 
     expect(stdoutLines.length, equals(expected.length),
-        reason: "Expected $stdoutLines to match $expected.");
+        reason: "Expected $stdoutLines to match ${JSON.encode(expected)}.");
 
     // TODO(nweiz): validate each event against the JSON schema when
     // patefacio/json_schema#4 is merged.
 
     // Remove excess trailing whitespace.
     for (var i = 0; i < stdoutLines.length; i++) {
       var event = JSON.decode(stdoutLines[i]);
       expect(event.remove("time"), new isInstanceOf<int>());
       event.remove("stackTrace");
       expect(event, equals(expected[i]));
@@ skipping 116 matching lines @@
 /// Returns the serialized metadata corresponding to [skip].
 Map _metadata({skip}) {
   if (skip == true) {
     return {"skip": true, "skipReason": null};
   } else if (skip is String) {
     return {"skip": true, "skipReason": skip};
   } else {
     return {"skip": false, "skipReason": null};
   }
 }