Expose Zones.

tests/lib/async/zone_value_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:expect/expect.dart';
+import 'package:async_helper/async_helper.dart';
+import 'dart:async';
+
+main() {
+  Completer done = new Completer();
+  List events = [];
+
+  // runGuarded calls run, captures the synchronous error (if any) and
+  // gives that one to handleUncaughtError.
+
+  Expect.identical(Zone.ROOT, Zone.current);
+  Zone forked;
+  Map zoneValues = new Map();
+  var foo = const Symbol("foo");
+  var bar = const Symbol("bar");
+  zoneValues[foo] = 499;
+  zoneValues[bar] = [];
+  forked = Zone.current.fork(zoneValues: zoneValues);
+
+  Expect.identical(Zone.ROOT, Zone.current);
+  Expect.isNull(Zone.current[foo]);
+  Expect.isNull(Zone.current[bar]);
+
+  forked.run(() {
+    Expect.equals(499, Zone.current[foo]);
+    Expect.listEquals([], Zone.current[bar]);
+    Zone.current[bar].add(42);
+  });
+  Expect.identical(Zone.ROOT, Zone.current);
+  Expect.isNull(Zone.current[foo]);
+  Expect.isNull(Zone.current[bar]);
+
+  forked.run(() {
+    Expect.equals(499, Zone.current[foo]);
+    Expect.listEquals([42], Zone.current[bar]);
+  });
+
+  zoneValues = new Map();
+  var gee = const Symbol("gee");
+  zoneValues[gee] = 99;
+  zoneValues[foo] = -499;
+  Zone forkedChild = forked.fork(zoneValues: zoneValues);
+
+  forkedChild.run(() {
+    Expect.equals(-499, Zone.current[foo]);
+    Expect.listEquals([42], Zone.current[bar]);
+    Expect.equals(99, Zone.current[gee]);
+  });
+}