Fix directory existence query error

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 "dart:async";
 import "dart:io";
 
 import "package:async_helper/async_helper.dart";
@@ skipping 585 matching lines @@
 
 
 testRename() {
   var temp1 = Directory.systemTemp.createTempSync('directory_test');
   var temp2 = Directory.systemTemp.createTempSync('directory_test');
   var temp3 = temp1.renameSync(temp2.path);
   Expect.isFalse(temp1.existsSync());
   Expect.isTrue(temp2.existsSync());
   Expect.equals(temp3.path, temp2.path);
 
-  temp2.rename(temp1.path).then((temp4) {
-    Expect.isFalse(temp3.existsSync());
-    Expect.isFalse(temp2.existsSync());
-    Expect.isTrue(temp1.existsSync());
-    Expect.isTrue(temp4.existsSync());
-    Expect.equals(temp1.path, temp4.path);
-    temp1.deleteSync(recursive: true);
-  });
+  var temp4 = temp2.renameSync(temp1.path);
+  Expect.isFalse(temp3.existsSync());
+  Expect.isFalse(temp2.existsSync());
+  Expect.isTrue(temp1.existsSync());
+  Expect.isTrue(temp4.existsSync());
+  Expect.equals(temp1.path, temp4.path);
+
+  String foo = '${temp4.path}/foo';
+  String bar = '${temp4.path}/bar';
+  new File(foo).createSync();
+  try {
+    new Directory(foo).renameSync(bar);
+    Expect.fail('Directory.rename should fail to rename a non-directory');
+  } catch (e) {
+    Expect.isTrue(e is FileSystemException);
+    if (Platform.isLinux || Platform.isMacOS) {
+      Expect.isTrue(e.osError.message.contains('Not a directory'));
+    }
+  }
+
+  temp1.deleteSync(recursive: true);
 }
 
 main() {
   DirectoryTest.testMain();
   NestedTempDirectoryTest.testMain();
   testCreateTempErrorSync();
   testCreateTempError();
   testCreateExistingSync();
   testCreateExisting();
   testCreateDirExistingFileSync();
   testCreateDirExistingFile();
   testRename();
 }