Add a path.formatUri method and release path 1.2.0.

pkg/path/test/url_test.dart

Index: pkg/path/test/url_test.dart
diff --git a/pkg/path/test/url_test.dart b/pkg/path/test/url_test.dart
index 58c7b929a6e235b1421504294c5b237b6dd95763..769a76f34a49b92523cdcdd5a4de765619d9c91a 100644
--- a/pkg/path/test/url_test.dart
+++ b/pkg/path/test/url_test.dart
@@ -741,4 +741,34 @@ main() {
     expect(context.toUri(r'_%7B_%7D_%60_%5E_%20_%22_%25_'),
         Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_'));
   });
+
+  group('formatUri', () {
+    test('with a file: URI', () {
+      expect(context.formatUri(Uri.parse('file:///root/path/a/b')),
+          'file:///root/path/a/b');
+    });
+
+    test('with an http: URI', () {
+      expect(context.formatUri(Uri.parse('http://dartlang.org/root/path/a/b')),
+          'a/b');
+      expect(context.formatUri(Uri.parse('http://dartlang.org/other/path/a/b')),
+          'http://dartlang.org/other/path/a/b');
+      expect(context.formatUri(Uri.parse('http://pub.dartlang.org/root/path')),
+          'http://pub.dartlang.org/root/path');
+      expect(context.formatUri(Uri.parse('http://dartlang.org/root/other')),
+          '../other');
+    });
+
+    test('with a relative URI', () {
+      expect(context.formatUri(Uri.parse('a/b')), 'a/b');
+    });
+
+    test('with a root-relative URI', () {
+      expect(context.formatUri(Uri.parse('/a/b')), '/a/b');
+    });
+
+    test('with a String', () {
+      expect(context.formatUri('a/b'), 'a/b');
+    });
+  });
 }