dojo.rb

require 'rubygems'
require 'spec'

class Account
  attr_reader :balance
  def self.find(pin)
    Accounts[pin]
  end

  def initialize(ref,balance=0)
    @symbol = ref
    @balance = balance
  end

  attr_reader :symbol



  def ==(that)
    @symbol == that.symbol
  end

  def withdraw_cash(amount)
    @balance -= amount
    amount
  end
end

class ATM
  def initialize
    @num_attempts = 0
  end

  def read_pin(pin)
    account = Account.find(pin)
    if account.nil?
      invalid_pin
    else
      return account
    end
  end

  def invalid_pin
    @num_attempts += 1
    if @num_attempts >= 3
      raise 'O NOES'
    end
  end
end

describe 'an atm' do
  let (:atm) {ATM.new}

  before(:each) do
    Account::Accounts = {7643 => Account.new(:alices_account,2000), 5954 => Account.new(:bobes_account,22400), 1562 => Account.new(:clydes_account)}

  end

  describe 'entering a pin' do
    context 'when a user enters a pin' do
      it 'returns the account for alice\'s pin' do
        atm.read_pin(7643).should == Account.new(:alices_account)
      end

      it 'returns the account for bobes pin' do
        atm.read_pin(5954).should == Account.new(:bobes_account)
      end
      
      it 'returns the account for clyde\'s pin' do
        atm.read_pin(1562).should == Account.new(:clydes_account)
      end
      it 'does not return the account for an invalid pin' do
        atm.read_pin(:invalid_apin).should be_nil
      end

      it 'returns the same account twice' do
        atm.read_pin(1562).should be_eql(atm.read_pin(1562))
      end

      it 'bobes account is not alices account' do
        atm.read_pin(1562).should_not be_eql(atm.read_pin(5954))
      end


    end

    context 'making three attempts to enter the pin' do
      it 'fails after entering the wrong pin 3 times' do
        2.times { atm.read_pin(:invalid_pin) }
        lambda { atm.read_pin(:ohmygoshinvalidpin) }.should raise_error
      end
    end

  end
  describe 'withdrawing money' do
    context 'from alices account' do
      it 'gives us money' do
        atm.read_pin(7643).withdraw_cash(80).should == 80
      end

      it 'debits the account' do
        account = atm.read_pin(7643)
        account.withdraw_cash(80)
        account.balance.should == 2000 - 80
      end

    end
    context 'from bobes account' do
      it 'debits the account' do
        account = atm.read_pin(5954)
        account.withdraw_cash(250)
        account.balance.should == 22400-250
      end
    end
  end
end