anchor.diff:  const sdkRoot = '/sdk';
   
   const _LIB_ASYNC =
  -    const _MockSdkLibrary('dart:async', '$sdkRoot/lib/async/async.dart', '''
  +    _MockSdkLibrary('dart:async', '$sdkRoot/lib/async/async.dart', '''
   library dart.async;
   
   part 'stream.dart';
   part 'future.dart';
   
   class Duration {}
  -''', const <String, String>{
  +''', <String, String>{
     '$sdkRoot/lib/async/stream.dart': r'''
   part of dart.async;
   abstract class Stream<T> {
  
positive.code: ''');
  
  const _LIB_CORE =
      const _MockSdkLibrary('dart:core', '$sdkRoot/lib/core/core.dart', '''
  library dart.core;
  
  import 'dart:async';
  
negative.code:     if (factory == null) {
        return super.createCacheFromSourceFactory(factory);
      }
      return AnalysisCache(
          <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
    }
  }
  