Objective | Process | User Stories | Running the program

Enable the user to create a bank account in which money can be deposited and withdrawn, and statements printed.

This solution was built using Ruby, and is based on the Makers week 10 tech test challenge 1. Click here for the original README.md.

• Should be able to interact with the code via a REPL like IRB. (Don't need to implement a command line interface that takes input from STDIN).
• Should have deposits and withdrawals.
• Should have account statement (date, amount, balance) printing.
• Data can be kept in memory (it doesn't need to be stored to a database).

Given a client makes a deposit of 1000 on 10-01-2012
And a deposit of 2000 on 13-01-2012
And a withdrawal of 500 on 14-01-2012
When she prints her bank statement
Then she would see

date || credit || debit || balance
14/01/2012 || || 500.00 || 2500.00
13/01/2012 || 2000.00 || || 3000.00
10/01/2012 || 1000.00 || || 1000.00

This is the approach I took for designing and creating this solution:

• Set up repo:

  • Initialize RSpec
  • Initialize Git
  • Setup code coverage (SimpleCov) and code quality (RuboCop) testers

• Verify areas of uncertainty with the client:

  • Overdraft allowed? Yes
  • Overdraft limit? No

• Create user stories (see below) based on the client's requirements

• Draw up class, state, method diagrams based on the user stories:

  • The classes were determined by considering the nouns in the user stories. I decided on three overall: transactions, amounts and statements, as they are all distinct objects in real life. This also helped with the encapsulation principle.
  • Accounts are made up of transactions, so the account class depends on the transaction objects.
  • Statements need information from an account, so the statement class depends on the account object.
  • Methods and attributes for each class were restricted to only what each class could be expected to do/have.

• Write the code, using TDD!

  • Methods were made to adhere to the Single Responsibility Principle as much as possible.
  • As many methods as possible were made private within their respective classes.

• Address edge cases eg. allow for amounts input as strings rather than integers/floats.

As a bank customer
I want to be able to open up an account
So I can use the bank's services.

As a bank customer
I want to be able to deposit money in my account
So it is safely stored.

As a user
I want to withdraw money
So I can buy stuff.

As a user
I want to print off my statement
So I can see my balance and what transfers I've made and when

$ git clone https://github.com/jasylwong/bank_tech_test.git
$ cd bank_tech_test

$ bundle
$ rspec # All tests passing, coverage: 100%
$ rubocop # No offenses

$ irb
> require './lib/load'
 => true 
> account = Account.new
 => #<Account:0x00007fe10c83f780> 
> account.deposit(350)
> account.withdraw(200)
> account.balance
 => 150.0 
> statement = Statement.new(account)
 => #<Statement:0x00007fe10b8a3f38> 
> statement.print_out
date || credit || debit || balance
03/24/20 || || 200.00 || 150.00
03/24/20 || 350.00 || || 350.00