- Implement Isolate.ping.

tests/isolate/ping_test.dart

Index: tests/isolate/ping_test.dart
===================================================================
--- tests/isolate/ping_test.dart	(revision 41942)
+++ tests/isolate/ping_test.dart	(working copy)
@@ -24,6 +24,10 @@
     List result = [];
     completer.future.then((echoPort) {
       reply.handler = (v) {
+        if (result.isEmpty) {
+          // Prevent messages overtaking each other on delivery.
+          echoPort.send(0);
+        }
         result.add(v);
         if (v == 0) {
           Expect.listEquals(["alive", "control", "event"],
@@ -38,7 +42,7 @@
                         "control index < 2");
           int eventIndex = result.indexOf("event");
           Expect.isTrue(eventIndex > result.indexOf(2), "event index > 2");
-          Expect.isTrue(eventIndex < result.indexOf(1), "event index < 1");
+          Expect.isTrue(eventIndex < result.indexOf(0), "event index < 0");
           reply.close();
           asyncEnd();
         }
@@ -58,7 +62,6 @@
       echoPort.send(2);
       isolate.ping(createPingPort("event"), Isolate.AS_EVENT);
       echoPort.send(1);
-      echoPort.send(0);
     });
   });
 }