Even easier observatory testing.

runtime/bin/vmservice/observatory/test/gc_test.dart

-// Copyright (c) 2014, 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:observatory/service_io.dart';
+import 'test_helper.dart';
 
-library gc_test;
+import 'dart:async';
 
-import 'test_helper.dart';
-import 'package:observatory/service_io.dart';
-import 'package:unittest/unittest.dart';
-
-import 'dart:io';
-
-// Expect at least this many GC events.
-int gcCountdown = 3;
-
-void onEvent(ServiceEvent event) {
-  if (event.eventType != 'GC') {
-    return;
-  }
-  if (--gcCountdown == 0) {
-    exit(0);
-  }
+void script() {
+  List<int> data;
+  var grow;
+  grow = (int iterations, int size, Duration duration) {
+    if (iterations <= 0) {
+      return;
+    }
+    data = new List<int>(size);
+    new Timer(duration, () => grow(iterations - 1, size, duration));
+  };
+  grow(100, 1 << 24, new Duration(seconds: 1));
 }
 
-main() {
-  String script = 'gc_script.dart';
-  var process = new TestLauncher(script);
-  process.launch().then((port) {
-    String addr = 'ws://localhost:$port/ws';
-    new WebSocketVM(new WebSocketVMTarget(addr)).get('vm')
-        .then((VM vm) {
-      vm.events.stream.listen(onEvent);
-    });
+var tests = [
+
+(Isolate isolate) {
+  Completer completer = new Completer();
+  // Expect at least this many GC events.
+  int gcCountdown = 3;
+  isolate.vm.events.stream.listen((ServiceEvent event) {
+    if (event.eventType == 'GC' && --gcCountdown == 0) {
+      completer.complete();
+    }
   });
-}
+  return completer.future;
+},
+
+];
+
+main(args) => runIsolateTests(args, tests, testeeConcurrent: script);