Add toUri and fromUri functions to pathos.

pkg/pathos/test/pathos_windows_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 pathos_windows_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:pathos/path.dart' as path;
 
 main() {
@@ skipping 423 matching lines @@
     expect(builder.withoutExtension(r'a\b\'), r'a\b\');
     expect(builder.withoutExtension(r'a\.'), r'a\.');
     expect(builder.withoutExtension(r'a\.b'), r'a\.b');
     expect(builder.withoutExtension(r'a.b\c'), r'a.b\c');
     expect(builder.withoutExtension(r'a/b.c/d'), r'a/b.c/d');
     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(r'a.b/c'), r'a.b/c');
     expect(builder.withoutExtension(r'a\b.c\'), r'a\b\');
   });
+
+  test('fromUri', () {
+    expect(builder.fromUri(Uri.parse('file:///C:/path/to/foo')),
+        r'C:\path\to\foo');
+    expect(builder.fromUri(Uri.parse('file://hostname/path/to/foo')),
+        r'\\hostname\path\to\foo');
+    expect(builder.fromUri(Uri.parse('file:///C:/')), r'C:\');
+    expect(builder.fromUri(Uri.parse('file://hostname/')), r'\\hostname\');
+    expect(builder.fromUri(Uri.parse('foo/bar')), r'foo\bar');
+    expect(builder.fromUri(Uri.parse('/C:/path/to/foo')), r'C:\path\to\foo');
+    expect(builder.fromUri(Uri.parse('///C:/path/to/foo')), r'C:\path\to\foo');
+    expect(builder.fromUri(Uri.parse('//hostname/path/to/foo')),
+        r'\\hostname\path\to\foo');
+    expect(() => builder.fromUri(Uri.parse('http://dartlang.org')),
+        throwsArgumentError);
+  });
+
+  test('toUri', () {
+    expect(builder.toUri(r'C:\path\to\foo'),
+        Uri.parse('file:///C:/path/to/foo'));
+    expect(builder.toUri(r'C:\'), Uri.parse('file:///C:/'));
+    expect(builder.toUri(r'\\hostname\'), Uri.parse('file://hostname/'));
+    expect(builder.toUri(r'foo\bar'), Uri.parse('foo/bar'));
+  });
 }