Change package scheduled_test to throw TestFailures rather than strings.

pkg/scheduled_test/test/descriptor/async_test.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.
 
 import 'dart:async';
 
 import 'package:scheduled_test/descriptor.dart' as d;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../metatest.dart';
@@ skipping 54 matching lines @@
       });
 
       d.async(pumpEventQueue().then((_) {
         return d.file('name.txt', 'contents');
       })).validate();
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.length, equals(1));
-      expect(errors.first.error,
-          matches(r"^File not found: '[^']+[\\/]name\.txt'\.$"));
+      expect(errors.first.error, new isInstanceOf<TestFailure>());

[nweiz, 2013/09/20 21:45:41]

The type of this exception isn't an important part of the interface. We don't
expect users of the library to catch it, and it may change in the future. As
such, we shouldn't test for it (here or elsewhere).

[Bill Hesse, 2013/09/23 17:15:25]

Done.

+      expect(errors.first.error.message,

[nweiz, 2013/09/20 21:45:41]

In keeping with the above, we should test [error.toString()] rather than
[error.message].

[Bill Hesse, 2013/09/23 17:15:25]

Done.

+             matches(r"^File not found: '[^']+[\\/]name\.txt'\.$"));
     });
   }, passing: ['test 2']);
 
   expectTestsPass("async().validate() forwards to directory().validate", () {
     test('test', () {
       scheduleSandbox();
 
       d.dir('dir', [
         d.file('file1.txt', 'contents1'),
         d.file('file2.txt', 'contents2')
@@ skipping 21 matching lines @@
         return d.dir('dir', [
           d.file('file1.txt', 'contents1'),
           d.file('file2.txt', 'contents2')
         ]);
       })).validate();
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.length, equals(1));
-      expect(errors.first.error,
+      expect(errors.first.error, new isInstanceOf<TestFailure>());
+      expect(errors.first.error.message,
           matches(r"^Directory not found: '[^']+[\\/]dir'\.$"));
     });
   }, passing: ['test 2']);
 }