anchor.diff:  import 'package:analyzer/task/dart.dart';
   import 'package:analyzer/task/general.dart';
   import 'package:analyzer/task/model.dart';
  +import 'package:front_end/src/scanner/scanner.dart' as fe;
   import 'package:test/test.dart';
   import 'package:test_reflective_loader/test_reflective_loader.dart';
   
  
positive.code: 
      computeResult(script, TOKEN_STREAM, matcher: isScanDartTask);
      expect(outputs[LINE_INFO], isNotNull);
      expect(outputs[SCAN_ERRORS], isEmpty);
      Token tokenStream = outputs[TOKEN_STREAM];
      expect(tokenStream, isNotNull);
      expect(tokenStream.lexeme, 'void');
  
negative.code:     _assertHasCore(outputs[IMPORTED_LIBRARIES], 2);
      expect(outputs[INCLUDED_PARTS], hasLength(1));
      expect(outputs[LIBRARY_SPECIFIC_UNITS], hasLength(2));
      if (fe.Scanner.useFasta) {
        // Missing closing brace error is reported by the Fasta scanner.
        expect(outputs[PARSE_ERRORS], hasLength(0));
      } else {
        expect(outputs[PARSE_ERRORS], hasLength(1));
      }
      expect(outputs[PARSED_UNIT], isNotNull);
      expect(outputs[REFERENCED_SOURCES], hasLength(5));
      expect(outputs[SOURCE_KIND], SourceKind.LIBRARY);
  