public async Task Handle_GivenExistCustomer_SholudBeWithOutExceptionAsync()
        {
            var command = new UpsertCustomerCommandHandler(_context);

            var existCustomer = new UpsertCustomerCommand()
            {
                Id = 1, FirstName = "saji2", LastName = "Rei", DateOfBirth = "18/06/2000", BankAccountNumber = "sadasd", Email = "*****@*****.**", PhoneNumber = "+989399158667"
            };

            var result = await command.Handle(existCustomer, CancellationToken.None);

            Assert.IsType <Unit>(result);
        }
        public async Task Handle_GivenNewCustomer_SholudBeWithOutExceptionAsync()
        {
            var command = new UpsertCustomerCommandHandler(_context);

            var newCustomer = new UpsertCustomerCommand()
            {
                FirstName         = "saji2",
                LastName          = "rei2",
                DateOfBirth       = "20/10/1990",
                Email             = "*****@*****.**",
                PhoneNumber       = "12345678/9",
                BankAccountNumber = "544"
            };

            var result = await command.Handle(newCustomer, CancellationToken.None);

            Assert.IsType <Unit>(result);
        }