Fix an error in multipart_test

test/multipart_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 'package:http/http.dart' as http;
 import 'package:http_parser/http_parser.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 78 matching lines @@
   });
 
   test('with a unicode field value', () {
     var request = new http.MultipartRequest('POST', dummyUrl);
     request.fields['field'] = 'vⱥlūe';
 
     expect(request, bodyMatches('''
         --{{boundary}}
         content-disposition: form-data; name="field"
         content-type: text/plain; charset=utf-8
+        content-transfer-encoding: binary
+
 
         vⱥlūe
         --{{boundary}}--
         '''));
   });
 
   test('with a unicode filename', () {
     var request = new http.MultipartRequest('POST', dummyUrl);
     request.files.add(new http.MultipartFile.fromString('file', 'contents',
         filename: 'fïlēname.txt'));
@@ skipping 115 matching lines @@
     expect(request, bodyMatches('''
         --{{boundary}}
         content-type: application/octet-stream
         content-disposition: form-data; name="file"
 
         hello
         --{{boundary}}--
         '''));
   });
 }