anchor.diff:                contentType: 'foobar');
           }
   
  -        validateServerRequest(e, http.BaseRequest request, List<int> data) {
  +        Future<http.StreamedResponse> validateServerRequest(
  +            e, http.BaseRequest request, List<int> data) {
             return new Future.sync(() {
               var h = e['headers'];
               var r = e['response'];
  
positive.code: import 'package:http/http.dart' as http;
  import 'package:test/test.dart';
  
  const String USER_AGENT = 'google-api-dart-client test.client/0.1.0-dev';
  
  class HttpServerMock extends http.BaseClient {
    Function _callback;
    bool _expectJson;
  
    void register(Function callback, bool expectJson) {
      _callback = callback;
      _expectJson = expectJson;
    }
  
negative.code:       testString(String msg, String expectedBase64) {
          var msgBytes = utf8.encode(msg);
  
          Stream<List<int>> singleByteStream(List<int> msgBytes) {
            var controller = new StreamController<List<int>>();
            for (var byte in msgBytes) {
              controller.add([byte]);
            }
  