Fix error handling in analysis.getError.

pkg/analysis_server/test/analysis/get_errors_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.analysis.get_errors;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analysis_server/src/protocol.dart';
@@ skipping 29 matching lines @@
 ''');
     return waitForTasksFinished().then((_) {
       return _getErrors(testFile).then((List<AnalysisError> errors) {
         expect(errors, hasLength(1));
       });
     });
   }
 
   test_fileDoesNotExist() {
     String file = '$projectPath/doesNotExist.dart';
-    return _getErrors(file).then((List<AnalysisError> errors) {
-      expect(errors, isEmpty);
-    });
+    return _checkInvalid(file);
   }
 
   test_fileWithoutContext() {
     String file = '/outside.dart';
     addFile(file, '''
 main() {
   print(42);
 }
 ''');
-    return _getErrors(file).then((List<AnalysisError> errors) {
-      expect(errors, isEmpty);
-    });
+    return _checkInvalid(file);
   }
 
   test_hasErrors() {
     addTestFile('''
 main() {
   print(42)
 }
 ''');
     return _getErrors(testFile).then((List<AnalysisError> errors) {
       expect(errors, hasLength(1));
@@ skipping 20 matching lines @@
 
   test_removeContextAfterRequest() {
     addTestFile('''
 main() {
   print(42)
 }
 ''');
     // handle the request synchronously
     Request request = _createGetErrorsRequest();
     server.handleRequest(request);
-    // remove context, causes sending a 'cancelled' error
+    // remove context, causes sending an "invalid file" error
     {
       Folder projectFolder = resourceProvider.getResource(projectPath);
       server.contextDirectoryManager.removeContext(projectFolder);
     }
     // wait for an error response
     return serverChannel.waitForResponse(request).then((Response response) {
-      var result = new AnalysisGetErrorsResult.fromResponse(response);
-      expect(result.errors, isEmpty);
-      RequestError error = response.error;
-      expect(error, isNotNull);
-      expect(error.code, RequestErrorCode.GET_ERRORS_ERROR);
+      expect(response.error, isNotNull);
+      expect(response.error.code, RequestErrorCode.GET_ERRORS_INVALID_FILE);
     });
   }
 
   Request _createGetErrorsRequest() {
     return new AnalysisGetErrorsParams(testFile).toRequest(requestId);
   }
 
   Future<List<AnalysisError>> _getErrors(String file) {
     Request request = _createGetErrorsRequest();
     return serverChannel.sendRequest(request).then((Response response) {
       return new AnalysisGetErrorsResult.fromResponse(response).errors;
     });
   }
+
+  Future _checkInvalid(String file) {
+    Request request = _createGetErrorsRequest();
+    return serverChannel.sendRequest(request).then((Response response) {
+      expect(response.error, isNotNull);
+      expect(response.error.code, RequestErrorCode.GET_ERRORS_INVALID_FILE);
+    });
+  }
 }