Change package scheduled_test to throw TestFailures rather than strings.

pkg/scheduled_test/test/descriptor/pattern_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 'package:scheduled_test/descriptor.dart' as d;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../metatest.dart';
 import 'utils.dart';
 
@@ skipping 50 matching lines @@
       currentSchedule.onException.schedule(() {
         errors = currentSchedule.errors;
       });
 
       d.filePattern(new RegExp(r'f..'), 'bar').validate();
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.length, equals(1));
-      expect(errors.first.error,
+      expect(errors.first.error.toString(),
           matches(r"^No entry found in '[^']+' matching /f\.\./\.$"));
     });
   }, passing: ['test 2']);
 
   expectTestsPass("pattern().validate() fails if there's a file matching the "
       "pattern but not the entry", () {
     var errors;
     test('test 1', () {
       scheduleSandbox();
 
       currentSchedule.onException.schedule(() {
         errors = currentSchedule.errors;
       });
 
       d.file('foo', 'bap').create();
       d.filePattern(new RegExp(r'f..'), 'bar').validate();
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.length, equals(1));
-      expect(errors.first.error,
+      expect(errors.first.error.toString(),
           matches(r"^Caught error\n"
               r"| File 'foo' should contain:\n"
               r"| | bar\n"
               r"| but actually contained:\n"
               r"| X bap\n"
               r"while validating\n"
               r"| foo$"));
     });
   }, passing: ['test 2']);
 
@@ skipping 12 matching lines @@
       ]).create();
 
       d.dirPattern(new RegExp(r'f..'), [
         d.file('bar', 'baz')
       ]).validate();
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.length, equals(1));
-      expect(errors.first.error,
+      expect(errors.first.error.toString(),
           matches(r"^Caught error\n"
               r"| File 'bar' should contain:\n"
               r"| | baz\n"
               r"| but actually contained:\n"
               r"| X bap"
               r"while validating\n"
               r"| foo\n"
               r"| '-- bar$"));
     });
   }, passing: ['test 2']);
@@ skipping 10 matching lines @@
 
       d.file('foo', 'bar').create();
       d.file('fee', 'bar').create();
       d.file('faa', 'bar').create();
       d.filePattern(new RegExp(r'f..'), 'bar').validate();
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.length, equals(1));
-      expect(errors.first.error, matches(
+      expect(errors.first.error.toString(), matches(
               r"^Multiple valid entries found in '[^']+' matching "
                   r"\/f\.\./:\n"
               r"\* faa\n"
               r"\* fee\n"
               r"\* foo$"));
     });
   }, passing: ['test 2']);
 }