Expose Zones.

tests/lib/async/catch_errors27_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:async_helper/async_helper.dart';
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'catch_errors.dart';
 
 main() {
   asyncStart();
+  Completer done = new Completer();
+
   var events = [];
   StreamController controller;
   Stream stream;
   // Test that the first listen on a `asBroadcastStream` determines the
   // zone the subscription lives in. The inner listen happens first, and
   // the outer listener must not see the error since it would cross a
   // zone boundary. It is therefore given to the inner `catchErrors`.
   catchErrors(() {
     catchErrors(() {
       controller = new StreamController();
       stream = controller.stream
         .map((x) {
           events.add("map $x");
           return x + 100;
         })
         .asBroadcastStream();
       stream
         .transform(new StreamTransformer(
             handleError: (e, sink) => sink.add("error $e")))
         .listen((x) { events.add("stream $x"); });
       runAsync(() {
         controller.add(1);
         // Errors are not allowed to traverse boundaries, but in this case the
         // first listener of the broadcast stream is in the same error-zone. So
         // this should work.
         controller.addError(2);
         controller.close();
       });
-    }).listen((x) { events.add(x); })
-      .asFuture().then((_) { events.add("inner done"); });
+    }).listen((x) {
+                events.add(x);
+                if (x == 2) done.complete(true);
+              })
+      .asFuture().then((_) { Expect.fail("Unexpected callback"); });
     stream.listen((x) { events.add("stream2 $x"); });
   }).listen((x) { events.add("outer: $x"); },
-            onDone: () {
-              Expect.listEquals(["map 1",
-                                 "stream 101",
-                                 "stream2 101",
-                                 "stream error 2",
-                                 2, // Caught by the inner `catchErrors`.
-                                 "inner done",
-                                ],
-                                events);
-              asyncEnd();
-            });
+            onDone: () { Expect.fail("Unexpected callback"); });
+
+  done.future.whenComplete(() {
+    // Give handlers time to run.
+    Timer.run(() {
+      Expect.listEquals(["map 1",
+                          "stream 101",
+                          "stream2 101",
+                          "stream error 2",
+                          2, // Caught by the inner `catchErrors`.
+                        ],
+                        events);
+      asyncEnd();
+    });
+  });
 }