Specify when 'sortMembers' will return an error.

pkg/analysis_server/test/integration/integration_test_methods.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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Convenience methods for running integration tests
@@ skipping 1186 matching lines @@
       if (checkTypes) {
         expect(result, isEditGetRefactoringResult);
       }
       return result;
     });
   }
 
   /**
    * Sort all of the directives, unit and class members of the given Dart file.
    *
+   * It is an error if the file does not exist or has scan or parse errors.
+   *
    * Parameters
    *
    * file ( FilePath )
    *
    *   The Dart file to sort.
    *
    * Returns
    *
    * edit ( SourceFileEdit )
    *
@@ skipping 284 matching lines @@
       case "execution.launchData":
         expect(params, isExecutionLaunchDataParams);
         _onExecutionLaunchData.add(params);
         break;
       default:
         fail('Unexpected notification: $event');
         break;
     }
   }
 }