public void Test1()
        {
            var SqLite    = new SqliteConnection("Filename=:memory:");
            var DBOptions = new DbContextOptionsBuilder <DBContextClass>().UseSqlite(SqLite).Options;

            SqLite.Open();
            using (var db = new DBContextClass(DBOptions))
            {
                db.Database.Migrate();
                var clients = new Client();
                clients.FName    = "John";
                clients.LName    = "Smith";
                clients.UserName = "******";
                clients.Password = "******";
                db.Add(clients);
                db.SaveChanges();
            }
            using (var db = new DBContextClass(DBOptions))
            {
                var clients = db.Clients
                              .Where(b => b.FName == "John")
                              .OrderBy(b => b.ClientID)
                              .ToList()
                              .First();
                Assert.Equal("John", clients.FName);
            }
        }