Add a regression test for bug 2235.

tests/isolate/v2_spawn_function_custom_class_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.
+
+// Create a user-defined class in a new isolate.
+//
+// Regression test for vm bug 2235: We were forgetting to finalize
+// classes in new isolates started using the v2 api.
+
+#library('spawn_tests');
+#import('dart:isolate');
+#import('../../lib/unittest/unittest.dart');
+
+class MyClass {
+  var myVar = 'there';
+  myFunc(msg) {
+    return '$msg $myVar';
+  }
+}
+
+child() {
+  port.receive((msg, reply) {
+      reply.send('re: ${new MyClass().myFunc(msg)}');
+    });
+}
+
+main() {
+  test('message - reply chain', () {

[Ivan Posva, 2012/05/29 21:55:58]

What bothers me here is that we are in a circular dependency. The test framework
itself depends on isolates to be working properly and it is used to test
isolates. Siggi, any suggestion to address this?

[Siggi Cherem (dart-lang), 2012/06/05 21:49:51]

It bothers me too.

The only reason we use dart:isolate in the unittest library is that we basically
need a platform independent way to run code at the end of the event loop. We use
messages within the same isolate to achieve this. That means that we are not
depending on 'spawn' for the unittest library, but we use port send/receive.
That's also why I didn't convert port_tests to use unittest.dart.

If we can provide a way to get a platform independent 'defer' in some 'dart:'
library, we could get rid of this dependence. Note, this platform independent
'defer' is needed also to fix some bugs in the 'future' code.

+    ReceivePort port = new ReceivePort();
+    port.receive(expectAsync(msg, _) {
+      port.close();
+      expect(msg).equals('re: hi there');
+    });
+
+    SendPort s = spawnFunction(child);
+    s.send('hi', port.toSendPort());
+  });
+}