Sharing metatest logic between unittest and scheduled_test

pkg/scheduled_test/test/utils.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.
 
 library test_utils;
 
 import 'dart:async';
 
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:scheduled_test/src/utils.dart';
 import 'package:scheduled_test/src/mock_clock.dart' as mock_clock;
 
-import 'metatest.dart';
+import 'package:metatest/metatest.dart';
 
 export 'package:scheduled_test/src/utils.dart';
 
 /// Wraps [input] to provide a timeout. If [input] completes before
 /// [milliseconds] have passed, then the return value completes in the same way.
 /// However, if [milliseconds] pass before [input] has completed, [onTimeout] is
 /// run and its result is passed to [input] (with chaining, if it returns a
 /// [Future]).
 ///
 /// Note that timing out will not cancel the asynchronous operation behind
@@ skipping 57 matching lines @@
 
       testBody();
     });
 
     test('validate errors', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       validator(errors);
     });
   }, passing: ['validate errors']);
 }