anchor.diff:  
   import 'dart:io' show File, Process;
   
  -import '../testing.dart' show dartSdk;
  +import '../testing.dart' show startDart;
   
   import 'log.dart' show isVerbose;
   
  
positive.code: Future<Null> analyzeUris(Uri analysisOptions, Uri packages, List<Uri> uris,
      List<RegExp> exclude) async {
    if (uris.isEmpty) return;
    const String analyzerPath = "bin/dartanalyzer";
    Uri analyzer = dartSdk.resolve(analyzerPath);
    if (!await new File.fromUri(analyzer).exists()) {
      throw "Couldn't find '$analyzerPath' in '${dartSdk.toFilePath()}'";
    }
    List<String> arguments = <String>[
      "--packages=${packages.toFilePath()}",
  
negative.code:     print("Running dartanalyzer.");
    }
    Stopwatch sw = new Stopwatch()..start();
    Process process = await startDart(analyzer, arguments);
    process.stdin.close();
    Future stdoutFuture = parseAnalyzerOutput(process.stdout).toList();
    Future stderrFuture = parseAnalyzerOutput(process.stderr).toList();
  