gistfile1.rbx

require 'rubygems'
require 'spec'

## implementatie
class Calculator
  attr_reader :result
  
  def initialize(a = 0)
    @result = a
  end
  
  def telop(a, b)
    a+b
  end
  
  def vermenigvuldig(a,b)
    a*b
  end
  
  def plus(a)  
    Calculator.new(@result + a)
  end
end

## test
describe Calculator do
  it "zou moeten kunnen optellen" do
    calc = Calculator.new
    calc.telop(2, 3).should == 5
  end
  
  it "zou moeten kunnen vermenigvuldigen" do
    calc = Calculator.new
    calc.vermenigvuldig(2,3).should == 6
  end
  
  it do
    calc = Calculator.new(5)
    calc.plus(5).plus(3).result.should == 13
  end
end