Catch exceptions in refactorings and return them as a SERVER_ERROR.

pkg/analysis_server/test/edit/refactoring_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.edit.refactoring;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analysis_server/src/protocol.dart';
@@ skipping 246 matching lines @@
     return sendExtractRequest(offset, length, name, extractAll);
   }
 
   Future<Response> sendStringSuffixRequest(String search, String suffix,
       String name, bool extractAll) {
     int offset = findOffset(search + suffix);
     int length = search.length;
     return sendExtractRequest(offset, length, name, extractAll);
   }
 
+  void tearDown() {
+    test_simulateRefactoringException = false;
+    super.tearDown();
+  }
+
   test_extractAll() {
     addTestFile('''
 main() {
   print(1 + 2);
   print(1 + 2);
 }
 ''');
     return assertSuccessfulRefactoring(() {
       return sendStringRequest('1 + 2', 'res', true);
     }, '''
@@ skipping 72 matching lines @@
 }
 ''');
     return getRefactoringResult(() {
       return sendStringRequest('1 + 2', 'res', true);
     }).then((result) {
       ExtractLocalVariableFeedback feedback = result.feedback;
       expect(feedback.offsets, [findOffset('1 + 2'), findOffset('1 +  2')]);
       expect(feedback.lengths, [5, 6]);
     });
   }
+
+  test_serverError() {
+    test_simulateRefactoringException = true;
+    addTestFile('''
+main() {
+  print(1 + 2);
+}
+''');
+    return waitForTasksFinished().then((_) {
+      return sendStringRequest('1 + 2', 'res', true).then((response) {
+        expect(response.error, isNotNull);
+      });
+    });
+  }
 }
 
 
 @ReflectiveTestCase()
 class ExtractMethodTest extends _AbstractGetRefactoring_Test {
   int offset;
   int length;
   String name = 'res';
   ExtractMethodOptions options;
 
@@ skipping 1270 matching lines @@
   }
 
   @override
   void setUp() {
     super.setUp();
     server.handlers = [new EditDomainHandler(server),];
     createProject();
     handler = new EditDomainHandler(server);
   }
 }