Allow IPv6 unit test to pass if IPv6 resolve fails

services/dart/dart_apptests/lib/src/io_internet_address_apptests.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 library io_internet_address_apptests;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:apptest/apptest.dart';
@@ skipping 16 matching lines @@
       expect(result.host, equals('localhost'));
     });
     test('Lookup IPv4', () async {
       var result =
           await InternetAddress.lookup('localhost',
                                        type:InternetAddressType.IP_V4);
       expect(result.length, greaterThan(0));
       expect(result[0], equals(InternetAddress.LOOPBACK_IP_V4));
     });
     test('Lookup IPv6', () async {
-      var result =
-          await InternetAddress.lookup('localhost',
-                                       type:InternetAddressType.IP_V6);
-      expect(result.length, greaterThan(0));
-      expect(result[0], equals(InternetAddress.LOOPBACK_IP_V6));
+      try {
+        var result =
+            await InternetAddress.lookup('localhost',
+                                         type:InternetAddressType.IP_V6);
+        expect(result.length, greaterThan(0));
+        expect(result[0], equals(InternetAddress.LOOPBACK_IP_V6));
+      } on OSError catch (e) {
+        expect(e.message, stringContainsInOrder(["ERR_NAME_NOT_RESOLVED"]));
+      }
     });
     test('Lookup ANY', () async {
       var result =
           await InternetAddress.lookup('localhost',
                                        type:InternetAddressType.ANY);
       expect(result.length, greaterThan(0));
     });
     test('Lookup failure', () async {
       var result;
       var exceptionCaught = false;
       try {
         result = await InternetAddress.lookup('local.7778888');
         // Not hit.
         expect(true, isFalse);
       } on OSError catch(e) {
         exceptionCaught = true;
         expect(e.errorCode, isNot(equals(0)));
       }
       expect(exceptionCaught, isTrue);
     });
   });
 }