isolates in frog: playing with API improvements

tests/isolate/src/APIv2_spawnBrowserNegativeTest.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.
+
+// Negative test to make sure that we are reaching all assertions.
+#library('spawn_tests');
+#import("../../../client/testing/unittest/unittest.dart");
+#import("dart:dom"); // import added so test.dart can treat this as a webtest.
+
+child(ReceivePort port) {
+  port.receive((msg, reply) => reply.send("re: $msg"));
+}
+
+main() {
+  asyncTest("message - reply chain", 1, () {
+    ReceivePort port = new ReceivePort();
+    port.receive((msg, _) {
+      expect(msg).equals("re: hello"); // should be hi, not hello
+      port.close();
+      callbackDone();
+    });
+
+    Isolate2 c = new Isolate2.fromCode(child);
+    c.sendPort.send("hi", port.toSendPort());
+  });
+}