Test empty strings arguments to path.join().

pkg/path/test/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 path.test.windows_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:path/path.dart' as path;
 
 main() {
@@ skipping 154 matching lines @@
       expect(builder.join('a', '/b', '/c', 'd'), r'a/b/c\d');
       expect(builder.join('a', r'c:\b', 'c', 'd'), r'c:\b\c\d');
       expect(builder.join('a', r'\\b', r'\\c', 'd'), r'\\c\d');
     });
 
     test('ignores trailing nulls', () {
       expect(builder.join('a', null), equals('a'));
       expect(builder.join('a', 'b', 'c', null, null), equals(r'a\b\c'));
     });
 
+    test('ignores empty strings', () {
+      expect(builder.join(''), '');
+      expect(builder.join('', ''), '');
+      expect(builder.join('', 'a'), 'a');
+      expect(builder.join('a', '', 'b', '', '', '', 'c'), r'a\b\c');
+      expect(builder.join('a', 'b', ''), r'a\b');
+    });
+
     test('disallows intermediate nulls', () {
       expect(() => builder.join('a', null, 'b'), throwsArgumentError);
       expect(() => builder.join(null, 'a'), throwsArgumentError);
     });
   });
 
   group('joinAll', () {
     test('allows more than eight parts', () {
       expect(builder.joinAll(['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']),
           r'a\b\c\d\e\f\g\h\i');
@@ skipping 284 matching lines @@
         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'));
     expect(builder.toUri(r'C:\path\to\foo#bar'),
         Uri.parse('file:///C:/path/to/foo%23bar'));
     expect(builder.toUri(r'\\hostname\path\to\foo#bar'),
         Uri.parse('file://hostname/path/to/foo%23bar'));
   });
 }