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 "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
+import "test_utils.dart" show retrySync;
 
 const ANY = InternetAddressType.ANY;
 
 void testIPv6toIPv6() {
   asyncStart();
   InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
     InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
-        ServerSocket.bind(serverAddr.first, 0).then((server) {
+      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) {
           socket.destroy();
         });
       });
     });
   });
 }
 
 void testIPv4toIPv6() {
   asyncStart();
   InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
-      ServerSocket.bind(serverAddr.first, 0).then((server) {
+    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) {
         socket.destroy();
       });
     });
   });
 }
 
 void testIPv6toIPv4() {
   asyncStart();
   InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
-      ServerSocket.bind("127.0.0.1", 0).then((server) {
+    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) {
+      Socket.connect(clientAddr.first, server.port).then((socket) {
+        socket.destroy();
+        server.close();
+        asyncEnd();
+        throw "Unexpected connect";

[kustermann, 2016/12/13 21:04:30]

This throw will be caught by the next line and silently swallowed.

I think you could fix it by adding a test closureÆ

  .catchError((e) { ... }, test: (exception) => exception is! String)

Or what would be even better:

Socket.connect(...).then((socket) {
  socket.destroy();
  throw 'Unexpected connect';
}).catchError((e) {
}, test: (exception) => exception is! String).whenComplete(() {
  server.close();
  asyncEnd();
});

The `whenComplete()` is like a finally block.

[Florian Schneider, 2016/12/13 22:12:33]

Thanks! Does Socket.connect ever throw a String?

I'll try use onError instead. Seems more concise as well.

[kustermann, 2016/12/13 22:55:29]

I don't think so. It's mostly some [SocketException] I think.

+      }).catchError((e) {
         server.close();
         asyncEnd();
       });
     });
   });
 }
 
 void testIPv4toIPv4() {
   asyncStart();
   ServerSocket.bind("127.0.0.1", 0).then((server) {
@@ skipping 38 matching lines @@
 
 void 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();
-              });
+              Socket.connect("127.0.0.1", server.port)
+                .then((socket) {
+                  socket.destroy();
+                  server.close();
+                  asyncEnd();
+                  throw "Unexpected connect";
+                })
+                .catchError((error) {
+                  server.close();
+                  asyncEnd();
+                });

[kustermann, 2016/12/13 21:04:30]

same here.

[Florian Schneider, 2016/12/13 22:12:33]

Done. Reformatted here as well to match the other tests.

             });
       });
 }
 
 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
+  retrySync(testIPv6toIPv4);           /// 06: ok
+  retrySync(testIPv4toIPv6_IPV6Only);  /// 07: ok

[kustermann, 2016/12/13 21:04:30]

You can't use retrySync, because these functions are async (they return "void",
but they do not run synchronously).

Maybe the best way would be to just use await/async syntax, make them return a
Future, and use the existing retry method.

[Florian Schneider, 2016/12/13 22:12:33]

Aaah. Async code. The void confusd me.

Done. (Strangely, tests were passing with retrySync, but maybe I didn't hit a
flaky failure)

 }