Very simple version of Isolates.

tests/isolate/message_stream2_test.dart

-// Copyright (c) 2012, 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.
-
-// Dart test program for testing serialization of messages.
-// VMOptions=--enable_type_checks --enable_asserts
-
-library Message2Test;
-import 'dart:isolate';
-import '../../pkg/unittest/lib/unittest.dart';
-
-// ---------------------------------------------------------------------------
-// Message passing test 2.
-// ---------------------------------------------------------------------------
-
-class MessageTest {
-  static void mapEqualsDeep(Map expected, Map actual) {
-    expect(expected, isMap);
-    expect(actual, isMap);
-    expect(actual.length, expected.length);
-    testForEachMap(key, value) {
-      if (value is List) {
-        listEqualsDeep(value, actual[key]);
-      } else {
-        expect(actual[key], value);
-      }
-    }
-    expected.forEach(testForEachMap);
-  }
-
-  static void listEqualsDeep(List expected, List actual) {
-    for (int i = 0; i < expected.length; i++) {
-      if (expected[i] is List) {
-        listEqualsDeep(expected[i], actual[i]);
-      } else if (expected[i] is Map) {
-        mapEqualsDeep(expected[i], actual[i]);
-      } else {
-        expect(actual[i], expected[i]);
-      }
-    }
-  }
-}
-
-void pingPong() {
-  bool isFirst = true;
-  IsolateSink replyTo;
-  stream.listen((var message) {
-    if (isFirst) {
-      isFirst = false;
-      replyTo = message;
-      return;
-    }
-    // Bounce the received object back so that the sender
-    // can make sure that the object matches.
-    replyTo.add(message);
-  });
-}
-
-main() {
-  test("map is equal after it is sent back and forth", () {
-    IsolateSink remote = streamSpawnFunction(pingPong);
-    Map m = new Map();
-    m[1] = "eins";
-    m[2] = "deux";
-    m[3] = "tre";
-    m[4] = "four";
-    MessageBox box = new MessageBox();
-    remote.add(box.sink);
-    remote.add(m);
-    box.stream.listen(expectAsync1((var received) {
-      MessageTest.mapEqualsDeep(m, received);
-      remote.close();
-      box.stream.close();
-    }));
-  });
-}