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