#gunmacs InsertionSort

gistfile1.rb

require 'pry'
require 'test/unit'

class Array
  def insertion_sort
    ary = self.dup

    (1...size).each do |i|
      (i).downto(1) do |j|
        ary[j], ary[j - 1] = ary[j - 1], ary[j] if ary[j] < ary[j - 1]
      end
    end

    ary
  end
end

class ArrayTest < Test::Unit::TestCase
  def test_insertion_sort
    assert_equal([], [].insertion_sort)
    assert_equal([1], [1].insertion_sort)
    assert_equal([1, 2], [2, 1].insertion_sort)
    assert_equal([1, 2, 3, 4], [2, 4, 3, 1].insertion_sort)
    assert_equal([1, 2, 3, 4, 5], [5, 2, 4, 3, 1].insertion_sort)
  end
end