anchor.diff:      Map request, args;
       var _id, data, author;
       DataProviderMock dataProvider;
  -    generatorType generator;
       var _generator;
  +
  +    DataProvider generator(args) => _generator.handle(args);
   
       void verifyGeneratorCalledOnceWithArgs(args) {
         _generator.getLogs().verify(happenedOnce);
  
positive.code: }
  class FutureMock extends Mock implements Future {}
  
  typedef DataProvider generatorType(var args);
  
  void main() {
    group("Publisher", () {
  
  
negative.code:       dataProvider = new DataProviderMock();
        _generator = new Mock()
            ..when(callsTo("handle")).alwaysReturn(dataProvider);
      });
  
      test("publish collection.", () {
  