Handle special characters in path<->uri conversion.

pkg/path/test/url_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.
 
 import 'package:unittest/unittest.dart';
 import 'package:path/path.dart' as path;
 
 main() {
   var builder = new path.Builder(style: path.Style.url,
       root: 'http://dartlang.org/root/path');
@@ skipping 647 matching lines @@
     expect(builder.withoutExtension('a/.'), 'a/.');
     expect(builder.withoutExtension('a/.b'), 'a/.b');
     expect(builder.withoutExtension('a.b/c'), 'a.b/c');
     expect(builder.withoutExtension(r'a.b\c'), r'a');
     expect(builder.withoutExtension(r'a/b\c'), r'a/b\c');
     expect(builder.withoutExtension(r'a/b\c.d'), r'a/b\c');
     expect(builder.withoutExtension('a/b.c/'), 'a/b/');
     expect(builder.withoutExtension('a/b.c//'), 'a/b//');
   });
 
-
   test('fromUri', () {
     expect(builder.fromUri(Uri.parse('http://dartlang.org/path/to/foo')),
         'http://dartlang.org/path/to/foo');
     expect(builder.fromUri(Uri.parse('http://dartlang.org/path/to/foo/')),
         'http://dartlang.org/path/to/foo/');
     expect(builder.fromUri(Uri.parse('file:///path/to/foo')),
         'file:///path/to/foo');
     expect(builder.fromUri(Uri.parse('foo/bar')), 'foo/bar');
     expect(builder.fromUri(Uri.parse('http://dartlang.org/path/to/foo%23bar')),
         'http://dartlang.org/path/to/foo%23bar');
+    // Since the resulting "path" is also a URL, special characters should
+    // remain percent-encoded in the result.
+    expect(builder.fromUri(Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_')),
+        r'_%7B_%7D_%60_%5E_%20_%22_%25_');
   });
 
   test('toUri', () {
     expect(builder.toUri('http://dartlang.org/path/to/foo'),
         Uri.parse('http://dartlang.org/path/to/foo'));
     expect(builder.toUri('http://dartlang.org/path/to/foo/'),
         Uri.parse('http://dartlang.org/path/to/foo/'));
     expect(builder.toUri('file:///path/to/foo'),
         Uri.parse('file:///path/to/foo'));
     expect(builder.toUri('foo/bar'), Uri.parse('foo/bar'));
     expect(builder.toUri('http://dartlang.org/path/to/foo%23bar'),
         Uri.parse('http://dartlang.org/path/to/foo%23bar'));
+    // Since the input path is also a URI, special characters should already
+    // be percent encoded there too.
+    expect(builder.toUri(r'http://foo.com/_%7B_%7D_%60_%5E_%20_%22_%25_'),
+        Uri.parse('http://foo.com/_%7B_%7D_%60_%5E_%20_%22_%25_'));
+    expect(builder.toUri(r'_%7B_%7D_%60_%5E_%20_%22_%25_'),
+        Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_'));
   });
 }