Bank Accounts

We will be working with the concept of bank accounts in order to explore more object-oriented code as well as a few other new topics.

Baseline Setup

1. This is an individual, stage 1 project.
2. Fork the project master.
3. Clone the forked repo: $ git clone [YOUR FORKED REPO URL]
4. cd into the dir create:d $ cd BankAccounts
5. Run git remote -v to verify the folder you are in corresponds to the fork you have created.
6. Run gem install minitest-skip to install an extra gem for testing (more on what this actually does later).

Testing

This is our first project with real tests! Following the instructions from the TDD lecture, there are three things in our project directory:

Rakefile
lib/
specs/

Each class you write (there will only be one until wave 3) should get its own file, lib/class_name.rb. The specs for that class will be in specs/class_name_spec.rb, and you can run all specs using rake.

For wave 1, all tests will be given to you - your job is to write code to make them pass. For waves 2 and 3, we supply descriptions of the tests, but you have to write them yourself.

Wave 1

Learning Goals

• Create a class inside of a module
• Create methods inside the class to perform actions
• Learn how Ruby does error handling
• Verify code correctness by testing

Requirements

Create a Bank module which will contain your Account class and any future bank account logic.

Create an Account class which should have the following functionality:

• A new account should be created with an ID and an initial balance
• Should have a withdraw method that accepts a single parameter which represents the amount of money that will be withdrawn. This method should return the updated account balance.
• Should have a deposit method that accepts a single parameter which represents the amount of money that will be deposited. This method should return the updated account balance.
• Should be able to access the current balance of an account at any time.

Error handling

• A new account cannot be created with initial negative balance - this will raise an ArgumentError (Google this)
• The withdraw method does not allow the account to go negative. Instead it will output a warning message and return the original un-modified balance.

Optional:

Make sure to write tests for any optionals you implement!

• Create an Owner class which will store information about those who own the Accounts.
  • This should have info like name and address and any other identifying information that an account owner would have.
• Add an owner property to each Account to track information about who owns the account.
  • The Account can be created with an owner, OR you can create a method that will add the owner after the Account has already been created.

Wave 2

Learning Goals

• Create and use class methods
• Use a CSV file for loading data

Requirements

• Read through the "Wave 2" xdescribe block in specs/account_spec.rb
  • Change xdescribe to describe so that the block will run
  • Notice that there are a bunch of tests with descriptions, but none of them have any code
  • These tests are your responsibility! Fill them in as you work on the wave.
  • Follow good TDD practices. Remember the testing cycle: red-green-refactor.
• Update the Account class to be able to handle all of these fields from the CSV file used as input.
  • For example, manually choose the data from the first line of the CSV file and ensure you can create a new instance of your Account using that data
• Add the following class methods to your existing Account class
  • self.all - returns a collection of Account instances, representing all of the Accounts described in the CSV. See below for the CSV file specifications.
  • self.find(id) - returns an instance of Account where the value of the id field in the CSV matches the passed parameter.
    • Question: what should your program do if Account.find is called with an ID that doesn't exist?

CSV Data File

The data, in order in the CSV, consists of:

Field	Type	Description
ID	Integer	A unique identifier for that Account
Balance	Integer	The account balance amount, in cents (i.e., 150 would be $1.50)
OpenDate	Datetime	When the account was opened

Optional:

First, implement the optional requirement from Wave 1

Then, add the following class methods to your existing Owner class

• self.all - returns a collection of Owner instances, representing all of the Owners described in the CSV. See below for the CSV file specifications
• self.find(id) - returns an instance of Owner where the value of the id field in the CSV matches the passed parameter

CSV Data File

The data, in order in the CSV, consists of:

Field	Type	Description
ID	Integer	A unique identifier for that Owner
Last Name	String	The owner's last name
First Name	String	The owner's first name
Street Address	String	The owner's street address
City	String	The owner's city
State	String	The owner's state

To create the relationship between the accounts and the owners use the account_owners CSV file. The data for this file, in order in the CSV, consists of:

Field	Type	Description
Account ID	Integer	A unique identifier corresponding to an Account
Owner ID	Integer	A unique identifier corresponding to an Owner

This type of table, where records from other tables are associated with each other, is often called a join table. We'll talk about them as a class in a few weeks.

Wave 3

Learning Goals

• Use inheritance to share some behavior across classes
• Enhance functionality built in Wave 1

Requirements

For wave 3, you will create two new classes: SavingsAccount and CheckingAccount. Both should inherit behavior from the Account class. Each class should get its own file under the lib/ directory, and each already has a spec file with stub tests. The testing requirements are the same as in wave 2: fill in the tests as you go, and follow the red-green-refactor cycle.

SavingsAccount

Create a SavingsAccount class which should inherit behavior from the Account class. It should include the following updated functionality:

• The initial balance cannot be less than $10. If it is, this will raise an ArgumentError
• Updated withdrawal functionality:
  • Each withdrawal 'transaction' incurs a fee of $2 that is taken out of the balance.
  • Does not allow the account to go below the $10 minimum balance - Will output a warning message and return the original un-modified balance

It should include the following new method:

• #add_interest(rate): Calculate the interest on the balance and add the interest to the balance. Return the interest that was calculated and added to the balance (not the updated balance).
  • Input rate is assumed to be a percentage (i.e. 0.25).
  • The formula for calculating interest is balance * rate/100
    • Example: If the interest rate is 0.25 and the balance is $10,000, then the interest that is returned is $25 and the new balance becomes $10,025.

CheckingAccount

Create a CheckingAccount class which should inherit behavior from the Account class. It should include the following updated functionality:

• Updated withdrawal functionality:
  • Each withdrawal 'transaction' incurs a fee of $1 that is taken out of the balance. Returns the updated account balance.
    • Does not allow the account to go negative. Will output a warning message and return the original un-modified balance.
• #withdraw_using_check(amount): The input amount gets taken out of the account as a result of a check withdrawal. Returns the updated account balance.
  • Allows the account to go into overdraft up to -$10 but not any lower
  • The user is allowed three free check uses in one month, but any subsequent use adds a $2 transaction fee
• #reset_checks: Resets the number of checks used to zero

Optional:

Create a MoneyMarketAccount class which should inherit behavior from the Account class.

• A maximum of 6 transactions (deposits or withdrawals) are allowed per month on this account type
• The initial balance cannot be less than $10,000 - this will raise an ArgumentError
• Updated withdrawal logic:
  • If a withdrawal causes the balance to go below $10,000, a fee of $100 is imposed and no more transactions are allowed until the balance is increased using a deposit transaction.
  • Each transaction will be counted against the maximum number of transactions
• Updated deposit logic:
  • Each transaction will be counted against the maximum number of transactions
  • Exception to the above: A deposit performed to reach or exceed the minimum balance of $10,000 is not counted as part of the 6 transactions.
• #add_interest(rate): Calculate the interest on the balance and add the interest to the balance. Return the interest that was calculated and added to the balance (not the updated balance).
  • Note** This is the same as the SavingsAccount interest.
• #reset_transactions: Resets the number of transactions to zero