Pump the event queue manually rather than using a timer.

pkg/scheduled_test/test/metatest.dart

 // Copyright (c) 2013, 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.
 
 /// A test library for testing test libraries? We must go deeper.
 ///
 /// Since unit testing code tends to use a lot of global state, it can be tough
 /// to test. This library manages it by running each test case in a child
 /// isolate, then reporting the results back to the parent isolate.
 library metatest;
 
 import 'dart:async';
 import 'dart:isolate';
 
 import '../../../pkg/path/lib/path.dart' as path;
 import 'package:scheduled_test/src/utils.dart';
 import 'package:unittest/unittest.dart';
 
+import 'utils.dart';
+
 /// Declares a test with the given [description] and [body]. [body] corresponds
 /// to the `main` method of a test file, and will be run in an isolate. By
 /// default, this expects that all tests defined in [body] pass, but if
 /// [passing] is passed, only tests listed there are expected to pass.
 void expectTestsPass(String description, void body(), {List<String> passing}) {
   _setUpTest(description, body, (results) {
     if (_hasError(results)) {
       throw 'Expected all tests to pass, but got error(s):\n'
           '${_summarizeTests(results)}';
     } else if (passing == null) {
@@ skipping 167 matching lines @@
         "message": testCase.message,
         "result": testCase.result,
         "stackTrace": testCase.stackTrace
       }).toList()
     });
   }
 
   void onInit() {}
   void onDone(bool success) {}
 }