Stress test for comparing analysis performed in two AnalysisContext instances with different option…

pkg/analyzer/lib/src/context/builder.dart

 // Copyright (c) 2016, 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.src.context.context_builder;
 
 import 'dart:collection';
 import 'dart:core' hide Resource;
 import 'dart:io' as io;
 
@@ skipping 129 matching lines @@
     return context;
   }
 
   Map<String, List<Folder>> convertPackagesToMap(Packages packages) {
     if (packages == null || packages == Packages.noPackages) {
       return null;
     }
     Map<String, List<Folder>> folderMap = new HashMap<String, List<Folder>>();
     packages.asMap().forEach((String packagePath, Uri uri) {
       String path = resourceProvider.pathContext.fromUri(uri);
+      if (path.endsWith(resourceProvider.pathContext.separator)) {
+        path = path.substring(0, path.length - 1);
+      }
       folderMap[packagePath] = [resourceProvider.getFolder(path)];
     });
     return folderMap;
   }
 
 //  void _processAnalysisOptions(
 //      AnalysisContext context, Map<String, YamlNode> optionMap) {
 //    List<OptionsProcessor> optionsProcessors =
 //        AnalysisEngine.instance.optionsPlugin.optionsProcessors;
 //    try {
@@ skipping 117 matching lines @@
         SdkDescription description = new SdkDescription(paths, options);
         DartSdk dartSdk = sdkManager.getSdk(description, () {
           if (extFilePaths.isNotEmpty) {
             embedderSdk.addExtensions(extResolver.urlMappings);
           }
           embedderSdk.analysisOptions = options;
           embedderSdk.useSummary = sdkManager.canUseSummaries;
           return embedderSdk;
         });
         return dartSdk;
-      } else if (extFilePaths != null) {
+      } else if (extFilePaths != null && extFilePaths.isNotEmpty) {
         //
         // We have an extension file, but no embedder file.
         //
         String sdkPath = sdkManager.defaultSdkDirectory;
         List<String> paths = <String>[sdkPath];
         paths.addAll(extFilePaths);
         SdkDescription description = new SdkDescription(paths, options);
         return sdkManager.getSdk(description, () {
           DirectoryBasedDartSdk sdk =
               new DirectoryBasedDartSdk(new JavaFile(sdkPath));
@@ skipping 49 matching lines @@
       }
       file = folder
           .getChildAssumingFile(AnalysisEngine.ANALYSIS_OPTIONS_YAML_FILE);
       if (file.exists) {
         return file;
       }
     }
     return null;
   }
 }