add warning for deprecated .analysis_options file name

pkg/analyzer/test/src/task/options_test.dart

 // Copyright (c) 2015, 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 analyzer.test.src.task.options_test;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/source/analysis_options_provider.dart';
 import 'package:analyzer/source/error_processor.dart';
 import 'package:analyzer/src/generated/engine.dart';
@@ skipping 125 matching lines @@
     configureContext('''
 analyzer:
   strong-mode: foo
 ''');
     expect(analysisOptions.strongMode, false);
   }
 }
 
 @reflectiveTest
 class GenerateNewOptionsErrorsTaskTest extends GenerateOptionsErrorsTaskTest {
+  bool get isOptionsFileDeprecated => false;
   String get optionsFilePath => '/${AnalysisEngine.ANALYSIS_OPTIONS_YAML_FILE}';
 }
 
 @reflectiveTest
 class GenerateOldOptionsErrorsTaskTest extends GenerateOptionsErrorsTaskTest {
+  bool get isOptionsFileDeprecated => true;
   String get optionsFilePath => '/${AnalysisEngine.ANALYSIS_OPTIONS_FILE}';
 }
 
 abstract class GenerateOptionsErrorsTaskTest extends AbstractContextTest {
   Source source;
 
+  bool get isOptionsFileDeprecated;
+
   String get optionsFilePath;
+
   LineInfo lineInfo(String source) =>
       GenerateOptionsErrorsTask.computeLineInfo(source);
 
   @override
   setUp() {
     super.setUp();
     source = newSource(optionsFilePath);
   }
 
   test_buildInputs() {
@@ skipping 36 matching lines @@
     GenerateOptionsErrorsTask task =
         new GenerateOptionsErrorsTask(null, source);
     expect(task.description, isNotNull);
   }
 
   test_descriptor() {
     TaskDescriptor descriptor = GenerateOptionsErrorsTask.DESCRIPTOR;
     expect(descriptor, isNotNull);
   }
 
+  @override
+  void computeResult(AnalysisTarget target, ResultDescriptor result,
+      {isInstanceOf matcher: null}) {
+    super.computeResult(target, result, matcher: matcher);
+    if (isOptionsFileDeprecated) {
+      bool found = false;
+      var errors = outputs[ANALYSIS_OPTIONS_ERRORS] as List<dynamic>;
+      for (var error in errors) {
+        if (error is AnalysisError &&
+            error.errorCode ==
+                AnalysisOptionsWarningCode
+                    .DEPRECATED_ANALYSIS_OPTIONS_FILE_NAME) {
+          errors.remove(error);
+          found = true;
+          break;
+        }
+      }
+      if (!found) {
+        fail('Expected deprecated analysis options file name warning');
+      }
+    }
+  }
+
   test_perform_bad_yaml() {
     String code = r'''
 :
 ''';
     AnalysisTarget target = newSource(optionsFilePath, code);
     computeResult(target, ANALYSIS_OPTIONS_ERRORS);
     expect(task, isGenerateOptionsErrorsTask);
     List<AnalysisError> errors =
         outputs[ANALYSIS_OPTIONS_ERRORS] as List<AnalysisError>;
     expect(errors, hasLength(1));
@@ skipping 244 matching lines @@
     var options = optionsProvider.getOptionsFromString(source);
     var errors = validator.validate(options);
     expect(errors.map((AnalysisError e) => e.errorCode),
         unorderedEquals(expected));
   }
 }
 
 class TestRule extends LintRule {
   TestRule() : super(name: 'fantastic_test_rule');
 }