Update dart:io tests to use asyncStart/asyncEnd

tests/standalone/io/secure_server_client_certificate_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 "dart:async";
+import "dart:io";
+
+import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 import "package:path/path.dart";
-import "dart:async";
-import "dart:io";
-import "dart:isolate";
 
 const HOST_NAME = "localhost";
 const CERTIFICATE = "localhost_cert";
 
 void testClientCertificate() {
-  ReceivePort port = new ReceivePort();
+  asyncStart();
   SecureServerSocket.bind(HOST_NAME,
                           0,
                           CERTIFICATE,
                           requestClientCertificate: true).then((server) {
     var clientEndFuture = SecureSocket.connect(HOST_NAME,
                                                server.port,
                                                sendClientCertificate: true);
     server.listen((serverEnd) {
       X509Certificate certificate = serverEnd.peerCertificate;
       Expect.isNotNull(certificate);
       Expect.equals("CN=localhost", certificate.subject);
       Expect.equals("CN=myauthority", certificate.issuer);
       clientEndFuture.then((clientEnd) {
         X509Certificate certificate = clientEnd.peerCertificate;
         Expect.isNotNull(certificate);
         Expect.equals("CN=localhost", certificate.subject);
         Expect.equals("CN=myauthority", certificate.issuer);
         clientEnd.close();
         serverEnd.close();
         server.close();
-        port.close();
+        asyncEnd();
       });
     });
   });
 }
 
 void testRequiredClientCertificate() {
-  ReceivePort port = new ReceivePort();
+  asyncStart();
   SecureServerSocket.bind(HOST_NAME,
                           0,
                           CERTIFICATE,
                           requireClientCertificate: true).then((server) {
     var clientEndFuture = SecureSocket.connect(HOST_NAME,
                                                server.port,
                                                sendClientCertificate: true);
     server.listen((serverEnd) {
       X509Certificate certificate = serverEnd.peerCertificate;
       Expect.isNotNull(certificate);
       Expect.equals("CN=localhost", certificate.subject);
       Expect.equals("CN=myauthority", certificate.issuer);
       clientEndFuture.then((clientEnd) {
         X509Certificate certificate = clientEnd.peerCertificate;
         Expect.isNotNull(certificate);
         Expect.equals("CN=localhost", certificate.subject);
         Expect.equals("CN=myauthority", certificate.issuer);
         clientEnd.close();
         serverEnd.close();
         server.close();
-        port.close();
+        asyncEnd();
       });
     });
   });
 }
 
 void testNoClientCertificate() {
-  ReceivePort port = new ReceivePort();
+  asyncStart();
   SecureServerSocket.bind(HOST_NAME,
                           0,
                           CERTIFICATE,
                           requestClientCertificate: true).then((server) {
     var clientEndFuture = SecureSocket.connect(HOST_NAME,
                                                server.port);
     server.listen((serverEnd) {
       X509Certificate certificate = serverEnd.peerCertificate;
       Expect.isNull(certificate);
       clientEndFuture.then((clientEnd) {
         clientEnd.close();
         serverEnd.close();
         server.close();
-        port.close();
+        asyncEnd();
       });
     });
   });
 }
 
 void testNoRequiredClientCertificate() {
-  ReceivePort port = new ReceivePort();
+  asyncStart();
   bool clientError = false;
   SecureServerSocket.bind(HOST_NAME,
                           0,
                           CERTIFICATE,
                           requireClientCertificate: true).then((server) {
     Future clientDone = SecureSocket.connect(HOST_NAME, server.port)
       .catchError((e) { clientError = true; });
     server.listen((serverEnd) {
       Expect.fail("Got a unverifiable connection");
     },
     onError: (e) {
       clientDone.then((_) {
         Expect.isTrue(clientError);
         server.close();
-        port.close();
+        asyncEnd();
       });
     });
   });
 }
 
 void main() {
   String certificateDatabase = join(dirname(Platform.script), 'pkcert');
   SecureSocket.initialize(database: certificateDatabase,
                           password: 'dartdart',
                           useBuiltinRoots: false);
 
   testClientCertificate();
   testRequiredClientCertificate();
   testNoClientCertificate();
   testNoRequiredClientCertificate();
 }