Add typed wrapper functions to delegate classes.

test/utils.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.
 
 /// Helper utilities for testing.
 import "dart:async";
 
 import "package:async/async.dart";
 import "package:test/test.dart";
 
 /// A zero-millisecond timer should wait until after all microtasks.
 Future flushMicrotasks() => new Future.delayed(Duration.ZERO);
 
 /// A generic unreachable callback function.
 ///
 /// Returns a function that fails the test if it is ever called.
 unreachable(String name) => ([a, b]) => fail("Unreachable: $name");
 
+// TODO(nweiz): Use the version of this in test when test#418 is fixed.
+/// A matcher that runs a callback in its own zone and asserts that that zone
+/// emits an error that matches [matcher].
+Matcher throwsZoned(matcher) => predicate((callback) {
+  var firstError = true;
+  runZoned(callback, onError: expectAsync((error, stackTrace) {
+    if (firstError) {
+      expect(error, matcher);
+      firstError = false;
+    } else {
+      registerException(error, stackTrace);
+    }
+  }, max: -1));
+  return true;
+});
+
+/// A matcher that runs a callback in its own zone and asserts that that zone
+/// emits a [CastError].
+final throwsZonedCastError = throwsZoned(new isInstanceOf<CastError>());
+
+/// A matcher that matches a callback or future that throws a [CastError].
+final throwsCastError = throwsA(new isInstanceOf<CastError>());
+
 /// A badly behaved stream which throws if it's ever listened to.
 ///
 /// Can be used to test cases where a stream should not be used.
 class UnusableStream extends Stream {
   listen(onData, {onError, onDone, cancelOnError}) {
     throw new UnimplementedError("Gotcha!");
   }
 }
 
 /// A dummy [StreamSink] for testing the routing of the [done] and [close]
@@ skipping 47 matching lines @@
     stream.listen(add, onError: addError, onDone: completer.complete);
     return completer.future;
   }
 
   Future close() {
     _isClosed = true;
     _doneCompleter.complete(new Future.microtask(_onDone));
     return done;
   }
 }