gistfile1.rb

class Array
  # Split an array into 10 pieces, yield 1/10th and the other 9/10ths.  Do this 10 times, returning a distinct
  # (no overlaps) 1/10th slice each time.
  def iterate_by_tenths(&block)
    self.each_slice((self.length / 10).ceil) do |tenth|
      yield(tenth, self - tenth)
    end
  end
end


# Tests
  def test_iterate_by_tenths
    array = (1..10).to_a
    concatenated_tenths = []

    array.iterate_by_tenths do |tenth, rest|
      assert_equal 1, tenth.size
      assert_equal 9, rest.size
      concatenated_tenths += tenth
    end 

    assert_equal array, concatenated_tenths 
  end 

  def test_iterate_by_tenths_not_even
    array = (1..25).to_a
    concatenated_tenths = []

    array.iterate_by_tenths do |tenth, rest|
      # Have to handle special case of last element
      if tenth == [25]
        assert_equal 1, tenth.size, tenth
        assert_equal 24, rest.size, rest
      else
        assert_equal 3, tenth.size, tenth
        assert_equal 22, rest.size, rest
      end
      concatenated_tenths += tenth
    end

    assert_equal array, concatenated_tenths
  end