Make VirtualDirectory redirect if the directory-path does not end with a tailing slash.

pkg/http_server/test/virtual_directory_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 'dart:io';
 
 import "package:http_server/http_server.dart";
 import 'package:path/path.dart' as pathos;
 import "package:unittest/unittest.dart";
@@ skipping 213 matching lines @@
           virDir.serveFile(new File(indexUri.toFilePath()), request);
         };
         virDir.serve(server);
         return getAsString(server.port, '/')
           .then((result) {
             expect(result, 'index file');
           });
       });
 
       _testVirDir('index-2', (server, dir) {
+        new Directory('${dir.path}/dir').createSync();
+        var virDir = new VirtualDirectory(dir.path);
+        virDir.allowDirectoryListing = true;
+        virDir.directoryHandler = (dir2, request) {
+          fail('not expected');
+        };
+        virDir.serve(server);
+        return getStatusCode(server.port, '/dir', followRedirects: false)
+          .then((result) {
+            expect(result, 301);
+          });
+      });
+
+      _testVirDir('index-3', (server, dir) {
         new File('${dir.path}/dir/index.html')
             ..createSync(recursive: true)
             ..writeAsStringSync('index file');
         var virDir = new VirtualDirectory(dir.path);
         virDir.allowDirectoryListing = true;
         virDir.directoryHandler = (dir2, request) {
           // Redirect directory-requests to index.html files.
           var indexUri = new Uri.file(dir2.path).resolve('index.html');
           virDir.serveFile(new File(indexUri.toFilePath()), request);
         };
         virDir.serve(server);
         return getAsString(server.port, '/dir')
           .then((result) {
             expect(result, 'index file');
           });
       });
+
+      _testVirDir('index-4', (server, dir) {
+        new File('${dir.path}/dir/index.html')
+            ..createSync(recursive: true)
+            ..writeAsStringSync('index file');
+        var virDir = new VirtualDirectory(dir.path);
+        virDir.allowDirectoryListing = true;
+        virDir.directoryHandler = (dir2, request) {
+          // Redirect directory-requests to index.html files.
+          var indexUri = new Uri.file(dir2.path).resolve('index.html');
+          virDir.serveFile(new File(indexUri.toFilePath()), request);
+        };
+        virDir.serve(server);
+        return getAsString(server.port, '/dir/')
+          .then((result) {
+            expect(result, 'index file');
+          });
+      });
     });
   });
 
   group('links', () {
     if (!Platform.isWindows) {
       group('follow-links', () {
         _testVirDir('dir-link', (server, dir) {
           var dir2 = new Directory('${dir.path}/dir2')..createSync();
           var link = new Link('${dir.path}/dir3')..createSync('dir2');
           var file = new File('${dir2.path}/file')..createSync();
@@ skipping 349 matching lines @@
 
         virDir.serve(server);
 
         return getAsString(server.port, '/')
           .then((result) {
             expect(result, 'file contents');
           });
     });
   });
 }