Fix for renaming import without an import prefix.

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

Index: pkg/analysis_server/test/services/refactoring/rename_import_test.dart
diff --git a/pkg/analysis_server/test/services/refactoring/rename_import_test.dart b/pkg/analysis_server/test/services/refactoring/rename_import_test.dart
index 6c31e3d69a28f350f207ef80830447fb684ed505..2d15c49627cdabcd9ce6dd4a0815e5b21dd41b2a 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_import_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_import_test.dart
@@ -5,10 +5,10 @@
 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';
 
 
@@ -168,6 +168,20 @@ main() {
 ''');
   }
 
+  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);