employee_compensation.rb

require 'minitest/autorun'
require 'minitest/spec'

#:nodoc:
class TestCompensation < Minitest::Test
  def setup
    @compensation = Compensation.new
  end

  describe 'when worked less than 12 months' do
    it 'will not receive compensation' do
      salary = 1000
      (1..11).each do |months|
        assert_equal Compensation.calculate(salary, months), 0
      end
    end
  end

  describe 'when worked more than 12 months' do
    it 'will receive compensation' do
      # exactly 1 year
      assert_equal Compensation.calculate(1000, 12.0), 1000
      # > 1 year
      assert_equal Compensation.calculate(1000, 13.0), 1000
      # > 1 year and < 1.5 years
      assert_equal Compensation.calculate(1000, 17.0), 1000
      # exactly 1.5 years
      assert_equal Compensation.calculate(1000, 18.0), 2000
      #  > 1.5 years < 2 years
      assert_equal Compensation.calculate(1000, 23.0), 2000
      # exactly 2 years
      assert_equal Compensation.calculate(1000, 24.0), 2000
    end
  end
end

#:nodoc:
class Compensation
  #
  # Calculate employee compensation based on salary and worked months.
  # Receive compensation only if worked more than 12 months. After that, she
  # receives a salary per year or any fraction of 6 months or more.
  #
  # @param [float] salary Employee salary
  # @param [float] months Worked months
  #
  # @return [float] Compensation amount
  #
  def self.calculate(salary, months)
    return 0 if months < 12.0

    (months / 12.0).round * salary
  end
end