Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/services/refactoring/abstract_rename.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 'package:analysis_server/plugin/protocol/protocol.dart' hide Element;
 import 'package:analysis_server/src/services/correction/namespace.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 import 'abstract_refactoring.dart';
 
 /**
  * The base class for all [RenameRefactoring] tests.
  */
 class RenameRefactoringTest extends RefactoringTest {
   RenameRefactoring refactoring;
 
   /**
@@ skipping 45 matching lines @@
     for (SourceFileEdit fileEdit in refactoringChange.edits) {
       for (SourceEdit edit in fileEdit.edits) {
         if (edit.id == id) {
           return edit;
         }
       }
     }
     return null;
   }
 }