Exercism: Gigasecond

readme.txt

# Gigasecond

Write a program that will calculate the date that someone turned or will celebrate their 1 Gs anniversary.

A gigasecond is one billion (10**9) seconds.


## Source

Chapter 9 in Chris Pine's online Learn to Program tutorial. [view source](http://pine.fm/LearnToProgram/?Chapter=09)

gigasecond.rb

require 'date'
require 'time'

class Gigasecond

  GIGASECONDs_IN_DAYS = 10**9 / (60 * 60 * 24)  # 1 day = 86,400 seconds

  def self.from(date)
    date + GIGASECONDs_IN_DAYS
  end

end

gigasecond_test.rb

require 'minitest/autorun'
require 'date'
require 'time'
require_relative 'gigasecond'

class GigasecondTest < MiniTest::Unit::TestCase

  def test_1
    gs = Gigasecond.from(Date.new(2011, 4, 25))
    assert_equal Date.new(2043, 1, 1), gs
  end

  def test_2
    gs = Gigasecond.from(Date.new(1977, 6, 13))
    assert_equal Date.new(2009, 2, 19), gs
  end

  def test_3
    gs = Gigasecond.from(Date.new(1959, 7, 19))
    assert_equal Date.new(1991, 3, 27), gs
  end

  def test_yourself
    your_birthday = Date.new(1982, 10, 16)
    gs = Gigasecond.from(your_birthday)
    assert_equal Date.new(2014, 6, 24), gs
  end

end