Let completers complete in the zone they were constructed in.

tests/standalone/io/async_catch_errors_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 'dart:async';
+import 'dart:isolate';
+import 'dart:io';
+
+Stream catchErrors(void body()) {

[Lasse Reichstein Nielsen, 2013/07/05 19:00:07]

As Anders pointed out: This function is not used.

[floitsch, 2013/07/08 10:45:51]

Done.

+  StreamController controller;
+
+  bool onError(e) {
+    controller.add(e);
+    return true;
+  }
+
+  void onDone() {
+    controller.close();
+  }
+
+  void onListen() {
+    runZonedExperimental(body, onError: onError, onDone: onDone);
+  }
+
+  controller = new StreamController(onListen: onListen);
+  return controller.stream;
+}
+
+var timeOutPort;
+
+void startTests() {

[Lasse Reichstein Nielsen, 2013/07/05 19:00:07]

Could you move the boilerplate code below main, so the tests come first, then
the main function that starts it all, and then the helper functions below. It's
hard to see what is what in this file.

[floitsch, 2013/07/08 10:45:51]

Done.

+  // We keep a ReceivePort open until all tests are done. This way the VM will
+  // hang if the callbacks are not invoked and the test will time out.
+  timeOutPort = new ReceivePort();
+}
+
+void finishTests() {
+  Expect.listEquals(["SocketException",
+                     "FileException"],
+                    events);

[Lasse Reichstein Nielsen, 2013/07/05 19:00:07]

Indentation is off by one.

[floitsch, 2013/07/08 10:45:51]

Done.

+  timeOutPort.close();
+}
+
+void launchNextTest() {
+  if (tests.isEmpty) {
+    finishTests();
+    return;
+  }
+  var test = tests.last;

[Lasse Reichstein Nielsen, 2013/07/05 19:00:07]

removeLast() ?

[floitsch, 2013/07/08 10:45:51]

Using iterator now.

+  tests.length--;
+  test();
+}
+
+void testSocketException() {
+   runZonedExperimental(() {
+    Socket.connect("4", 1).then((Socket s) {
+       Expect.fail("Socket should not be able to connect");
+     });
+   }, onError: (err) {
+     if (err is! SocketException) Expect.fail("Not expected error: $err");
+     events.add("SocketException");
+     launchNextTest();
+   });
+}
+
+void testFileException() {
+   runZonedExperimental(() {
+     new File("lol it's not a file\n").openRead().listen(null);
+   }, onError: (err) {
+     if (err is! FileException) Expect.fail("Not expected error: $err");
+     events.add("FileException");
+     launchNextTest();
+   });

[Lasse Reichstein Nielsen, 2013/07/05 19:00:07]

Could you return a Future that completes when you are done?
Then you could chain the tests using .then.

[floitsch, 2013/07/08 10:45:51]

Done.

+}
+
+var events = [];
+// In reverse order:

[Lasse Reichstein Nielsen, 2013/07/05 19:00:07]

Consider using a new Queue.from(your list) and use removeFirst, then you don't
have to reverse it. 
Or just use an index into the list that is incremented in launchNextTest. Or
just an Iterator, as Anders suggested.
The "reverse order" is just distracting.

[floitsch, 2013/07/08 10:45:51]

Changed to iterator and then to futures.

+var tests = [testFileException, testSocketException];
+
+
+main() {
+  startTests();
+  launchNextTest();
+}