Reapply "Fix URI encoding/decoding of + and space""

pkg/oauth2/test/authorization_code_grant_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 authorization_code_grant_test;
 
 import 'dart:io';
 import 'dart:json';
 import 'dart:uri';
 
@@ skipping 32 matching lines @@
     });
 
     test('builds the correct URL with scopes', () {
       var authorizationUrl = grant.getAuthorizationUrl(
           redirectUrl, scopes: ['scope', 'other/scope']);
       expect(authorizationUrl.toString(),
           equals('https://example.com/authorization'
               '?response_type=code'
               '&client_id=identifier'
               '&redirect_uri=http%3A%2F%2Fexample.com%2Fredirect'
-              '&scope=scope%20other%2Fscope'));
+              '&scope=scope+other%2Fscope'));
     });
 
     test('builds the correct URL with state', () {
       var authorizationUrl = grant.getAuthorizationUrl(
           redirectUrl, state: 'state');
       expect(authorizationUrl.toString(),
           equals('https://example.com/authorization'
               '?response_type=code'
               '&client_id=identifier'
               '&redirect_uri=http%3A%2F%2Fexample.com%2Fredirect'
@@ skipping 123 matching lines @@
       });
 
       expect(grant.handleAuthorizationCode('auth code'),
           completion(predicate((client) {
             expect(client.credentials.accessToken, equals('access token'));
             return true;
           })));
     });
   });
 }