Created
September 25, 2011 12:08
-
-
Save netikular/1240544 to your computer and use it in GitHub Desktop.
Answer to Ayende's blog post
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #From blog post http://ayende.com/blog/108545/the-tax-calculation-challenge | |
| require 'test/unit' | |
| class Rate | |
| def initialize(rate) | |
| @percent = rate[:percent] | |
| @min = rate[:min].to_f | |
| @max = rate[:max].to_f | |
| @range = @max - @min | |
| end | |
| def percent | |
| return (@percent / 100.00).round(2) | |
| end | |
| def taxible(amount) | |
| amount = amount.to_f | |
| return @range if ((amount - @max) > 0) | |
| return amount - @min if ((amount - @min) > 0) | |
| return 0.0 | |
| end | |
| def tax(amount) | |
| (self.taxible(amount).round(2) * (self.percent)) | |
| end | |
| end | |
| class TaxMan | |
| attr_accessor :rates,:amount | |
| def profit | |
| @rates.inject(0.0) do |memo, rate| | |
| memo = memo + rate.tax(@amount) | |
| memo.round(2) | |
| end | |
| end | |
| end | |
| #### TESTS | |
| # | |
| INFINITY = 1.0/0 | |
| DATA_RATES = [ | |
| { :percent => 10, :min =>0,:max => 5070}, | |
| { :percent => 14, :min =>5070,:max => 8660 }, | |
| { :percent => 23, :min =>8660,:max => 14070 }, | |
| { :percent => 30, :min =>14070,:max => 21240 }, | |
| { :percent => 33, :min =>21240,:max => 40230 }, | |
| { :percent => 45, :min =>40230,:max => INFINITY } | |
| ] | |
| class TaxesTest < Test::Unit::TestCase | |
| def setup | |
| @tax_man = TaxMan.new | |
| @tax_man.rates = DATA_RATES.map{|rate| Rate.new(rate)} | |
| end | |
| def test_should_do_the_first_level | |
| @tax_man.amount = 5000 | |
| assert_equal 500.0, @tax_man.profit | |
| end | |
| def test_should_do_the_boundry_test_first_level | |
| @tax_man.amount = 5070 | |
| assert_equal 507.0, @tax_man.profit | |
| end | |
| def test_should_do_the_bountry_test_second_level | |
| @tax_man.amount = 8660 | |
| assert_equal 1009.6, @tax_man.profit | |
| end | |
| def test_should_do_the_second_level | |
| @tax_man.amount = 5800 | |
| assert_equal 609.2, @tax_man.profit | |
| end | |
| def test_should_do_the_third_level | |
| @tax_man.amount = 9000 | |
| assert_equal 1087.8, @tax_man.profit | |
| end | |
| def test_should_do_the_fourth_level | |
| @tax_man.amount = 15000 | |
| assert_equal 2532.9, @tax_man.profit | |
| end | |
| def test_should_do_the_fifth_level | |
| @tax_man.amount = 50000 | |
| assert_equal 15068.1, @tax_man.profit | |
| end | |
| def test_find_the_amount_from_the_rate | |
| rate = Rate.new(DATA_RATES[0]) | |
| assert_equal 5070 , rate.taxible(9000) | |
| rate = Rate.new(DATA_RATES[1]) | |
| assert_equal 3590 , rate.taxible(9000) | |
| rate = Rate.new(DATA_RATES[2]) | |
| assert_equal 340 , rate.taxible(9000) | |
| rate = Rate.new(DATA_RATES[3]) | |
| assert_equal 0 , rate.taxible(9000) | |
| end | |
| end |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment