public void ShouldCreateToDoItemWithEmptyUser()
        {
            var createToDoItemInput = new CreateToDoItemInput { AssignedUserId = null, Description = Faker.Lorem.Sentence() };

            using (this.Repository.Record())
            {
                Expect.Call(this.DbContextScopeFactory.Create());
                Expect.Call(this.UserRepository.Get(string.Empty)).Constraints(Is.Equal(null)).Repeat.Never();
                Expect.Call(this.ToDoItemRepository.Add(null)).Constraints(Is.Anything()).Repeat.Once();
                Expect.Call(() => this.Logger.Info(Arg.Text.Contains("Creating ToDoItem for input:"))).Repeat.Once();
                Expect.Call(() => this.Logger.Info(Arg.Text.Contains("Created ToDoItem for input:"))).Repeat.Once();
            }

            using (this.Repository.Playback())
            {
                var toDoItemApplicationService = new ToDoItemApplicationService(
                    this.ToDoItemRepository,
                    this.UserRepository,
                    this.DbContextScopeFactory,
                    this.Mapper,
                    this.Logger);
                toDoItemApplicationService.CreateToDoItem(createToDoItemInput);
            }
        }