Add minimal yaml support to the engine

pkg/analyzer/test/src/task/dart_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.dart_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 3034 matching lines @@
   test_perform_doesNotExist() {
     _performParseTask(null);
     expect(outputs, hasLength(9));
     expect(outputs[EXPLICITLY_IMPORTED_LIBRARIES], hasLength(0));
     expect(outputs[EXPORTED_LIBRARIES], hasLength(0));
     _assertHasCore(outputs[IMPORTED_LIBRARIES], 1);
     expect(outputs[INCLUDED_PARTS], hasLength(0));
     expect(outputs[LIBRARY_SPECIFIC_UNITS], hasLength(1));
     expect(outputs[PARSE_ERRORS], hasLength(0));
     expect(outputs[PARSED_UNIT], isNotNull);
-    expect(outputs[SOURCE_KIND], SourceKind.UNKNOWN);
+    expect(outputs[SOURCE_KIND], SourceKind.LIBRARY);
     expect(outputs[UNITS], hasLength(1));
   }
 
   test_perform_enableAsync_false() {
     AnalysisOptionsImpl options = new AnalysisOptionsImpl();
     options.enableAsync = false;
     prepareAnalysisContext(options);
     _performParseTask(r'''
 import 'dart:async';
 class B {void foo() async {}}''');
@@ skipping 89 matching lines @@
     _assertHasCore(outputs[IMPORTED_LIBRARIES], 1);
     expect(outputs[INCLUDED_PARTS], hasLength(0));
     expect(outputs[LIBRARY_SPECIFIC_UNITS], hasLength(1));
     expect(outputs[PARSE_ERRORS], hasLength(0));
     expect(outputs[PARSED_UNIT], isNotNull);
     expect(outputs[SOURCE_KIND], SourceKind.PART);
     expect(outputs[UNITS], hasLength(1));
   }
 
   void _performParseTask(String content) {
-    source = newSource('/test.dart', content);
+    if (content == null) {
+      source = resourceProvider.getFile('/test.dart').createSource();
+    } else {
+      source = newSource('/test.dart', content);
+    }
     computeResult(source, PARSED_UNIT, matcher: isParseDartTask);
   }
 
   static void _assertHasCore(List<Source> sources, int lenght) {
     expect(sources, hasLength(lenght));
     expect(sources, contains(predicate((Source s) {
       return s.fullName.endsWith('core.dart');
     })));
   }
 }
@@ skipping 1699 matching lines @@
   /**
    * Fill [errorListener] with [result] errors in the current [task].
    */
   void _fillErrorListener(ResultDescriptor<List<AnalysisError>> result) {
     List<AnalysisError> errors = task.outputs[result];
     expect(errors, isNotNull, reason: result.name);
     errorListener = new GatheringErrorListener();
     errorListener.addAll(errors);
   }
 }