public void Add_User_Storage_File_Tests_Method()
        {
            fileStorage.Clear();

            var      date     = DateTimeOffset.Now;
            var      guid     = Guid.NewGuid();
            UserItem userItem = new UserItem()
            {
                ChatId             = 123,
                DateOfRegistration = date,
                FirstName          = "Null",
                Id      = guid,
                Message = "Null",
                Status  = StatusEnum.Null
            };

            fileStorage.AddUser(userItem);

            Assert.AreEqual(fileStorage.Count, 1);

            fileStorage.Clear();
        }