Very simple version of Isolates.

tests/lib/platform/isolate_test.dart

Index: tests/lib/platform/isolate_test.dart
diff --git a/tests/lib/platform/isolate_test.dart b/tests/lib/platform/isolate_test.dart
index b402383ae9f6e9e1a39d77d9f1f0ad6d4eed147d..b53f088a7e6cdd54e583be7fc6fc10c318fae42a 100644
--- a/tests/lib/platform/isolate_test.dart
+++ b/tests/lib/platform/isolate_test.dart
@@ -7,33 +7,49 @@ import "dart:platform" as platform;
 import "dart:isolate";
 import "package:unittest/unittest.dart";
 
+sendReceive(SendPort port, msg) {
+  var response = new ReceivePort();
+  port.send([msg, response.sendPort]);
+  return response.first;
+}
+
 main() {
-  var sendPort = spawnFunction(f);
-  expect(sendPort.call("platform.executable"), completion(platform.executable));
-  if (platform.script != null) {
-    expect(sendPort.call("platform.script").then((s) => s.path),
-           completion(endsWith('tests/lib/platform/isolate_test.dart')));
-  }
-  expect(sendPort.call("platform.packageRoot"),
-         completion(platform.packageRoot));
-  expect(sendPort.call("platform.executableArguments"),
-         completion(platform.executableArguments));
+  test("platform in isolate", () {
+    var response = new ReceivePort();
+    Isolate.spawn(f, response.sendPort);
+    response.first.then(expectAsync1((sendPort) {
+      expect(sendReceive(sendPort, "platform.executable"),
+            completion(platform.executable));
+      if (platform.script != null) {
+        expect(sendReceive(sendPort, "platform.script").then((s) => s.path),
+              completion(endsWith('tests/lib/platform/isolate_test.dart')));
+      }
+      expect(sendReceive(sendPort, "platform.packageRoot"),
+            completion(platform.packageRoot));
+      expect(sendReceive(sendPort, "platform.executableArguments"),
+            completion(platform.executableArguments));
+    }));
+  });
 }
 
-void f() {
+void f(initialReplyTo) {
+  var port = new ReceivePort();
+  initialReplyTo.send(port.sendPort);
   int count = 0;
-  port.receive((msg, reply) {
-    if (msg == "platform.executable") {
-      reply.send(platform.executable);
+  port.listen((msg) {
+    var data = msg[0];
+    var replyTo = msg[1];
+    if (data == "platform.executable") {
+      replyTo.send(platform.executable);
     }
-    if (msg == "platform.script") {
-      reply.send(platform.script);
+    if (data == "platform.script") {
+      replyTo.send(platform.script);
     }
-    if (msg == "platform.packageRoot") {
-      reply.send(platform.packageRoot);
+    if (data == "platform.packageRoot") {
+      replyTo.send(platform.packageRoot);
     }
-    if (msg == "platform.executableArguments") {
-      reply.send(platform.executableArguments);
+    if (data == "platform.executableArguments") {
+      replyTo.send(platform.executableArguments);
     }
     count++;
     if (count == 4) {