anchor.diff:    String _boundaryKey;
     bool _readingSources;
   
  +  List<String> allReceived = new List<String>();
  +
     void listener(String s) {
  +    allReceived.add(s);
       if (_boundaryKey == null) {
         const String RESULT_OUTPUT_SPACE = 'result ';
         if (s.startsWith(RESULT_OUTPUT_SPACE)) {
  
positive.code: 
    print("Did $compilations compilations and verifications in "
        "${stopwatch.elapsedMilliseconds} ms.");
  }
  
  // The below is copied from incremental_compiler_test.dart,
  
negative.code:       Directory testDir =
            new Directory.fromUri(dotPackage.parent.uri.resolve("test/"));
        if (!testDir.existsSync()) continue;
        if (testDir.toString().contains("packages/flutter_web_plugins/test/")) {
          // TODO(jensj): Figure out which tests are web-tests, and compile those
          // in a setup that can handle that.
          continue;
        }
        print("Go for $testDir");
        List<String> compilationErrors = await attemptStuff(
            tempDir, flutterPlatformDirectory, dotPackage, testDir);
        if (compilationErrors.isNotEmpty) {
          print("Notice that we had ${compilationErrors.length} "
              "compilation errors for $testDir");
          allCompilationErrors.addAll(compilationErrors);
        }
      } finally {
        tempDir.delete(recursive: true);
      }
    }
    if (allCompilationErrors.isNotEmpty) {
      print("Had a total of ${allCompilationErrors.length} compilation errors:");
      allCompilationErrors.forEach(print);
      throw "Had a total of ${allCompilationErrors.length} compilation errors";
    }
  }
  
  Future<List<String>> attemptStuff(
      Directory tempDir,
      Directory flutterPlatformDirectory,
      File dotPackage,
      Directory testDir) async {
    File dillFile = new File('${tempDir.path}/dill.dill');
    if (dillFile.existsSync()) {
      throw "$dillFile already exists.";
  