Calculate Vat

calculate_vat.gemspec

Gem::Specification.new do |s|
  s.name        = 'calculate_vat'
  s.version     = '0.1.1'
  s.platform    = Gem::Platform::RUBY
  s.author      = 'Andy Henson'
  s.email       = 'andy@elaptics.co.uk'
  s.summary     = 'Calculate VAT stuff!'
  s.description = 'Calculates UK VAT type stuff'

  s.files         = ['calculate_vat.rb']
  s.test_file     = 'calculate_vat_spec.rb'
  s.require_path  = '.'

  s.add_development_dependency('rspec', ["~> 2.0"])
end

calculate_vat.rb

module CalculateVat
  VAT_RATE = 20.0
  def gross(value)
    total = value + value * (VAT_RATE/100)
    total.round(2)
  end
end

calculate_vat_spec.rb

require File.expand_path('calculate_vat')

class ObjectWithCalculateVat
end

describe CalculateVat do

  let(:object) do
    object = ObjectWithCalculateVat.new
    object.extend(CalculateVat)
    object
  end

  context "calculating total price given a net amount" do
    it "should return total of net amount plus vat amount" do
      object.gross(10).should == 12.00
    end
  end
end