Fix for renaming import without an import prefix.

pkg/analysis_server/test/services/refactoring/rename_import_test.dart

 // Copyright (c) 2014, 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 test.services.refactoring.rename_import;
 
 import 'package:analysis_server/src/protocol.dart';
-import '../../reflective_tests.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:unittest/unittest.dart';
 
+import '../../reflective_tests.dart';
 import 'abstract_rename.dart';
 
 
 main() {
   groupSep = ' | ';
   runReflectiveTests(RenameImportTest);
 }
 
 
 @ReflectiveTestCase()
@@ skipping 139 matching lines @@
     // validate change
     return assertSuccessfulRefactoring('''
 import 'dart:math' as test;
 import 'dart:async';
 main() {
   Future f;
 }
 ''');
   }
 
+  test_oldName_empty() {
+    indexTestUnit('''
+import 'dart:math';
+import 'dart:async';
+main() {
+  Future f;
+}
+''');
+    // configure refactoring
+    _createRefactoring("import 'dart:async");
+    expect(refactoring.refactoringName, 'Rename Import Prefix');
+    expect(refactoring.oldName, '');
+  }
+
   void _createRefactoring(String search) {
     ImportDirective directive =
         findNodeAtString(search, (node) => node is ImportDirective);
     createRenameRefactoringForElement(directive.element);
   }
 }