anchor.diff:  
         //then
         verifyGeneratorCalledOnceWithArgs(args);
  -      dataProvider.getLogs(callsTo('diffFromVersion')).verify(happenedOnce);
  -      expect(result, equals(dataProvider.futureMock));
  +      var callToDiff = dataProvider.getLogs(callsTo('diffFromVersion'));
  +      callToDiff.verify(happenedOnce);
  +      expect(callToDiff.first.args.first, equals(5));
  +      expect(result, equals(dataProvider.responseFuture));
       });
   
       test("handle add.", () {
  
positive.code: import "dart:async";
  
  class DataProviderMock extends Mock implements DataProvider {
    final futureMock = new FutureMock();
  
    DataProviderMock() {
      when(callsTo("data")).alwaysReturn(futureMock);
      when(callsTo("diffFromVersion")).alwaysReturn(futureMock);
      when(callsTo("add")).alwaysReturn(futureMock);
      when(callsTo("change")).alwaysReturn(futureMock);
      when(callsTo("remove")).alwaysReturn(futureMock);
    }
  }
  class FutureMock extends Mock implements Future {}
  
  void main() {
    group("Publisher", () {
  
      Publisher publisher;
      Map request, args;
      DataProviderMock dataProvider;
      var generator, _generator;
  
      void verifyGeneratorCalledOnceWithArgs(args) {
        _generator.getLogs().verify(happenedOnce);
  
negative.code: 
        //then
        verifyGeneratorCalledOnceWithArgs(args);
        var callToDiff = dataProvider.getLogs(callsTo('remove'));
        callToDiff.verify(happenedOnce);
        expect(callToDiff.first.args[0], equals(_id));
        expect(callToDiff.first.args[1], equals(author));
        expect(result, equals(dataProvider.responseFuture));
      });
    });
  }
  