Teach the pub tests about --hostname.

sdk/lib/_internal/pub/test/pub_test.dart

 // Copyright (c) 2012, 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.
 
 library pub_tests;
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../lib/src/exit_codes.dart' as exit_codes;
 import 'test_pub.dart';
@@ skipping 201 matching lines @@
     integration('shows non-truncated help', () {
       schedulePub(args: ['help', 'serve'],
           output: '''
             Run a local web development server.
 
             By default, this serves "web/" and "test/", but an explicit list of 
             directories to serve can be provided as well.
 
             Usage: pub serve [directories...]
             -h, --help               Print usage information for this command.
+                --hostname           The hostname to listen on.
+                                     (defaults to "localhost")
+
                 --port               The base port to listen on.
                                      (defaults to "8080")
 
                 --[no-]dart2js       Compile Dart to JavaScript.
                                      (defaults to on)
 
                 --[no-]force-poll    Force the use of a polling filesystem watcher.
                 --mode               Mode to run transformers in.
                                      (defaults to "debug")
             ''');
@@ skipping 53 matching lines @@
             exitCode: exit_codes.USAGE);
     });
   });
 
   group('version', () {
     integration('displays the current version', () {
       schedulePub(args: ['version'], output: VERSION_STRING);
     });
   });
 }