Avoid double-// on directory listing.

tests/standalone/io/directory_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.
 //
 // Directory listing test.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
@@ skipping 67 matching lines @@
             listingDonePort.close();
           });
         });
 
     // Listing is asynchronous, so nothing should be listed at this
     // point.
     Expect.isFalse(listedDir);
     Expect.isFalse(listedFile);
   }
 
+  static void testListingTailingPaths() {
+    Directory directory = new Directory("").createTempSync();
+    Directory subDirectory = new Directory("${directory.path}/subdir/");
+    subDirectory.createSync();
+    File f = new File('${subDirectory.path}/file.txt');
+    f.createSync();
+
+    void test(entry) {
+      Expect.isFalse(entry.path.contains(new RegExp('[\\/][\\/]')));
+    }
+
+    subDirectory.listSync().forEach(test);
+
+    subDirectory.list().listen(test, onDone: () {
+      directory.deleteSync(recursive: true);
+    });
+  }
+
   static void testListNonExistent() {
     setupListerHandlers(Stream<FileSystemEntity> stream) {
       stream.listen(
           (_) => Expect.fail("Listing of non-existing directory should fail"),
           onError: (error) {
             Expect.isTrue(error is DirectoryException);
           });
     }
     new Directory("").createTemp().then((d) {
       d.delete().then((ignore) {
@@ skipping 292 matching lines @@
     var name = new File('.').fullPathSync();
     Directory current1 = new Directory(name);
     var path = new Path(name);
     Directory current2 = new Directory.fromPath(path);
     Expect.equals(current1.path, current2.path);
     Expect.isTrue(current1.existsSync());
   }
 
   static void testMain() {
     testListing();
+    testListingTailingPaths();
     testListNonExistent();
     testListTooLongName();
     testDeleteNonExistent();
     testDeleteTooLongName();
     testDeleteNonExistentSync();
     testDeleteTooLongNameSync();
     testExistsCreateDelete();
     testExistsCreateDeleteSync();
     testDeleteLinkSync();
     testDeleteLinkAsFileSync();
@@ skipping 205 matching lines @@
   testCreateTempErrorSync();
   testCreateTempError();
   testCreateExistingSync();
   testCreateExisting();
   testCreateDirExistingFileSync();
   testCreateDirExistingFile();
   testCreateRecursive();
   testCreateRecursiveSync();
   testRename();
 }