Allow [path.fromUri] to take a string as well as a URI.

pkg/path/test/posix_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 path.test.posix_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:path/path.dart' as path;
 
 import 'utils.dart';
@@ skipping 456 matching lines @@
     expect(context.withoutExtension('a/.'), 'a/.');
     expect(context.withoutExtension('a/.b'), 'a/.b');
     expect(context.withoutExtension('a.b/c'), 'a.b/c');
     expect(context.withoutExtension(r'a.b\c'), r'a');
     expect(context.withoutExtension(r'a/b\c'), r'a/b\c');
     expect(context.withoutExtension(r'a/b\c.d'), r'a/b\c');
     expect(context.withoutExtension('a/b.c/'), 'a/b/');
     expect(context.withoutExtension('a/b.c//'), 'a/b//');
   });
 
-  test('fromUri', () {
-    expect(context.fromUri(Uri.parse('file:///path/to/foo')), '/path/to/foo');
-    expect(context.fromUri(Uri.parse('file:///path/to/foo/')), '/path/to/foo/');
-    expect(context.fromUri(Uri.parse('file:///')), '/');
-    expect(context.fromUri(Uri.parse('foo/bar')), 'foo/bar');
-    expect(context.fromUri(Uri.parse('/path/to/foo')), '/path/to/foo');
-    expect(context.fromUri(Uri.parse('///path/to/foo')), '/path/to/foo');
-    expect(context.fromUri(Uri.parse('file:///path/to/foo%23bar')),
-        '/path/to/foo#bar');
-    expect(context.fromUri(Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_')),
-        r'_{_}_`_^_ _"_%_');
-    expect(() => context.fromUri(Uri.parse('http://dartlang.org')),
-        throwsArgumentError);
+  group('fromUri', () {
+    test('with a URI', () {
+      expect(context.fromUri(Uri.parse('file:///path/to/foo')), '/path/to/foo');
+      expect(context.fromUri(Uri.parse('file:///path/to/foo/')),
+          '/path/to/foo/');
+      expect(context.fromUri(Uri.parse('file:///')), '/');
+      expect(context.fromUri(Uri.parse('foo/bar')), 'foo/bar');
+      expect(context.fromUri(Uri.parse('/path/to/foo')), '/path/to/foo');
+      expect(context.fromUri(Uri.parse('///path/to/foo')), '/path/to/foo');
+      expect(context.fromUri(Uri.parse('file:///path/to/foo%23bar')),
+          '/path/to/foo#bar');
+      expect(context.fromUri(Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_')),
+          r'_{_}_`_^_ _"_%_');
+      expect(() => context.fromUri(Uri.parse('http://dartlang.org')),
+          throwsArgumentError);
+    });
+
+    test('with a string', () {
+      expect(context.fromUri('file:///path/to/foo'), '/path/to/foo');
+    });
   });
 
   test('toUri', () {
     expect(context.toUri('/path/to/foo'), Uri.parse('file:///path/to/foo'));
     expect(context.toUri('/path/to/foo/'), Uri.parse('file:///path/to/foo/'));
     expect(context.toUri('/'), Uri.parse('file:///'));
     expect(context.toUri('foo/bar'), Uri.parse('foo/bar'));
     expect(context.toUri('/path/to/foo#bar'),
         Uri.parse('file:///path/to/foo%23bar'));
     expect(context.toUri(r'/_{_}_`_^_ _"_%_'),
         Uri.parse('file:///_%7B_%7D_%60_%5E_%20_%22_%25_'));
     expect(context.toUri(r'_{_}_`_^_ _"_%_'),
         Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_'));
   });
 }