CLI program

CLI program

Add the structures for Customer and Account

Create the structures for customers and accounts in bankcore/bank.go

package bank

// Customer ...
type Customer struct {
    Name    string
    Address string
    Phone   string
}

// Account ...
type Account struct {
    Customer
    Number  int32
    Balance float64
}

Now, let’s add that validation in the tests, in bankcore/bank_test.go

package bank

import "testing"

func TestAccount(t *testing.T) {
    account := Account{
        Customer: Customer{
            Name:    "John",
            Address: "Los Angeles, California",
            Phone:   "(213) 555 0147",
        },
        Number:  1001,
        Balance: 0,
    }

    if account.Name == "" {
        t.Error("can't create an Account object")
    }
}

Implement the deposit method

In bankcore/bank_test.go add a couple of tests for testing the Deposit method.

// Test the deposit is updated properly
func TestDeposit(t *testing.T) {
    account := Account{
        Customer: Customer{
            Name:    "John",
            Address: "Los Angeles, California",
            Phone:   "(213) 555 0147",
        },
        Number:  1001,
        Balance: 0,
    }

    account.Deposit(10)

    if account.Balance != 10 {
        t.Error("balance is not being updated after a deposit")
    }
}

// Test the deposit is a negative amount
func TestDepositInvalid(t *testing.T) {
    account := Account{
        Customer: Customer{
            Name:    "John",
            Address: "Los Angeles, California",
            Phone:   "(213) 555 0147",
        },
        Number:  1001,
        Balance: 0,
    }

    if err := account.Deposit(-10); err == nil {
        t.Error("only positive numbers should be allowed to deposit")
    }
}

Now, let’s add the Deposit method in bankcore/bank.go:

func (a *Account) Deposit(amount float64) error {
    if amount <= 0 {
        return errors.New("the amount to deposit should be greater than zero")
    }

    a.Balance += amount
    return nil
}

Implement the withdraw method

Same, let’s add some tests in bankcore/bank_test.go:

// Test the withdraw is updated properly
func TestWithdraw(t *testing.T) {
    account := Account{
        Customer: Customer{
            Name:    "John",
            Address: "Los Angeles, California",
            Phone:   "(213) 555 0147",
        },
        Number:  1001,
        Balance: 0,
    }

    account.Deposit(10) // Personally I don't like depend on the Deposit method...
    account.Withdraw(10)

    if account.Balance != 0 {
        t.Error("balance is not being updated after withdraw")
    }
}

Then, let’s implement the Withdraw method in bankcore/bank.go:

// Withdraw ...
func (a *Account) Withdraw(amount float64) error {
    if amount <= 0 {
        return errors.New("the amount to withdraw should be greater than zero")
    }

    if a.Balance < amount {
        return errors.New("the amount to withdraw should be greater than the account's balance")
    }

    a.Balance -= amount
    return nil
}

We should add more tests in the bankcore/bank_test.go file for testing the Withdraw method.

Implement the statement method

Test in bankcore/bank_test.go the Statement method:

func TestStatement(t *testing.T) {
    account := Account{
        Customer: Customer{
            Name:    "John",
            Address: "Los Angeles, California",
            Phone:   "(213) 555 0147",
        },
        Number:  1001,
        Balance: 0,
    }

    account.Deposit(100)
    statement := account.Statement()
    if statement != "1001 - John - 100" {
        t.Error("statement doesn't have the proper format")
    }
}

Then, the code for the Statement method in bankcore/bank.go:

// Statement ...
func (a *Account) Statement() string {
    return fmt.Sprintf("%v - %v - %v", a.Number, a.Name, a.Balance)
}

These are the 3 action we need on the CLI 🎉

Next: part III