Provide more error-handling customization.

test/stream_channel_controller_test.dart

 // Copyright (c) 2016, 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:stream_channel/stream_channel.dart';
 import 'package:test/test.dart';
 
 import 'utils.dart';
 
 void main() {
   group("asynchronously", () {
     var controller;
     setUp(() {
       controller = new StreamChannelController();
     });
 
     test("forwards events from the local sink to the foreign stream", () {
       controller.local.sink..add(1)..add(2)..add(3)..close();
       expect(controller.foreign.stream.toList(), completion(equals([1, 2, 3])));
     });
 
     test("forwards events from the foreign sink to the local stream", () {
       controller.foreign.sink..add(1)..add(2)..add(3)..close();
       expect(controller.local.stream.toList(), completion(equals([1, 2, 3])));
     });
+
+    test("with allowForeignErrors: false, shuts down the connection if an "
+        "error is added to the foreign channel", () {
+      controller = new StreamChannelController(allowForeignErrors: false);
+
+      controller.foreign.sink.addError("oh no");
+      expect(controller.foreign.sink.done, throwsA("oh no"));
+      expect(controller.foreign.stream.toList(), completion(isEmpty));
+      expect(controller.local.sink.done, completes);
+      expect(controller.local.stream.toList(), completion(isEmpty));
+    });
   });
 
   group("synchronously", () {
     var controller;
     setUp(() {
       controller = new StreamChannelController(sync: true);
     });
 
     test("synchronously forwards events from the local sink to the foreign "
         "stream", () {
@@ skipping 39 matching lines @@
       expect(receivedEvent, isTrue);
 
       controller.foreign.sink.addError("oh no");
       expect(receivedError, isTrue);
 
       controller.foreign.sink.close();
       expect(receivedDone, isTrue);
     });
   });
 }