Fix flaky timeouts of socket_ipv6_test.

tests/standalone/io/socket_ipv6_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:io';
+import 'dart:async';
 
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
+import "test_utils.dart" show retry;
 
 const ANY = InternetAddressType.ANY;
 
-void testIPv6toIPv6() {
+Future testIPv6toIPv6() {
   asyncStart();
-  InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
-    InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
-        ServerSocket.bind(serverAddr.first, 0).then((server) {
+  return InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
+    return InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
+      return ServerSocket.bind(serverAddr.first, 0).then((server) {
         Expect.equals('::0', server.address.host);
         Expect.equals('::', server.address.address);
         server.listen((socket) {
           socket.destroy();
           server.close();
           asyncEnd();
         });
-        Socket.connect(clientAddr.first, server.port).then((socket) {
+        return Socket.connect(clientAddr.first, server.port).then((socket) {
           socket.destroy();
         });
       });
     });
   });
 }
 
-void testIPv4toIPv6() {
+Future testIPv4toIPv6() {
   asyncStart();
-  InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
-      ServerSocket.bind(serverAddr.first, 0).then((server) {
+  return InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
+    return ServerSocket.bind(serverAddr.first, 0).then((server) {
       Expect.equals('::0', server.address.host);
       Expect.equals('::', server.address.address);
       server.listen((socket) {
         socket.destroy();
         server.close();
         asyncEnd();
       });
-      Socket.connect("127.0.0.1", server.port).then((socket) {
+      return Socket.connect("127.0.0.1", server.port).then((socket) {
         socket.destroy();
       });
     });
   });
 }
 
-void testIPv6toIPv4() {
+Future testIPv6toIPv4() {
   asyncStart();
-  InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
-      ServerSocket.bind("127.0.0.1", 0).then((server) {
+  return InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
+    return ServerSocket.bind("127.0.0.1", 0).then((server) {
       Expect.equals('127.0.0.1', server.address.host);
       Expect.equals('127.0.0.1', server.address.address);
       server.listen((socket) {
         throw "Unexpected socket";
       });
-      Socket.connect(clientAddr.first, server.port).catchError((e) {
+      return Socket.connect(clientAddr.first, server.port).then((socket) {
+        socket.destroy();
+        throw "Unexpected connect";
+      }, onError: (e) {}).whenComplete(() {
         server.close();
         asyncEnd();
       });
     });
   });
 }
 
-void testIPv4toIPv4() {
+Future testIPv4toIPv4() {
   asyncStart();
-  ServerSocket.bind("127.0.0.1", 0).then((server) {
+  return ServerSocket.bind("127.0.0.1", 0).then((server) {
     Expect.equals('127.0.0.1', server.address.host);
     Expect.equals('127.0.0.1', server.address.address);
     server.listen((socket) {
       socket.destroy();
       server.close();
       asyncEnd();
     });
-    Socket.connect("127.0.0.1", server.port).then((socket) {
+    return Socket.connect("127.0.0.1", server.port).then((socket) {
       socket.destroy();
     });
   });
 }
 
-void testIPv6Lookup() {
+Future testIPv6Lookup() {
   asyncStart();
-  InternetAddress.lookup("::0", type: ANY).then((list) {
+  return InternetAddress.lookup("::0", type: ANY).then((list) {
     if (list.length < 0) throw "no address";
     for (var entry in list) {
       if (entry.type != InternetAddressType.IP_V6) {
         throw "Wrong IP type";
       }
     }
     asyncEnd();
   });
 }
 
-void testIPv4Lookup() {
+Future testIPv4Lookup() {
   asyncStart();
-  InternetAddress.lookup("127.0.0.1").then((list) {
+  return InternetAddress.lookup("127.0.0.1").then((list) {
     if (list.length < 0) throw "no address";
     for (var entry in list) {
       if (entry.type != InternetAddressType.IP_V4) {
         throw "Wrong IP type";
       }
     }
     asyncEnd();
   });
 }
 
-void testIPv4toIPv6_IPV6Only() {
+Future testIPv4toIPv6_IPV6Only() {
   asyncStart();
-  InternetAddress.lookup("::0", type: ANY)
-      .then((serverAddr) {
-        ServerSocket.bind(serverAddr.first, 0, v6Only: true)
-            .then((server) {
-              server.listen((socket) {
-                throw "Unexpected socket";
-              });
-              Socket.connect("127.0.0.1", server.port).catchError((error) {
-                server.close();
-                asyncEnd();
-              });
-            });
+  return InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
+    return ServerSocket.bind(serverAddr.first, 0, v6Only: true).then((server) {
+      server.listen((socket) {
+        throw "Unexpected socket";
       });
+      return Socket.connect("127.0.0.1", server.port).then((socket) {
+        socket.destroy();
+        throw "Unexpected connect";
+      }, onError: (e) {}).whenComplete(() {
+        server.close();
+        asyncEnd();
+      });
+    });
+  });
 }
 
 void main() {
-  testIPv6toIPv6();           /// none: ok
-  testIPv4toIPv6();           /// 01: ok
-  testIPv6toIPv4();           /// 02: ok
-  testIPv4toIPv4();           /// 03: ok
-  testIPv6Lookup();           /// 04: ok
-  testIPv4Lookup();           /// 05: ok
+  testIPv6toIPv6();                /// 01: ok
+  testIPv4toIPv6();                /// 02: ok
+  testIPv4toIPv4();                /// 03: ok
+  testIPv6Lookup();                /// 04: ok
+  testIPv4Lookup();                /// 05: ok
 
-  testIPv4toIPv6_IPV6Only();  /// 06: ok
+  retry(testIPv6toIPv4);           /// 06: ok
+  retry(testIPv4toIPv6_IPV6Only);  /// 07: ok
 }