Bubble sort in ruby

bubble_sort.rb

# Bubble sort (inefficient for sorting large data volumes)

require 'test/unit'

def sort(a)
  swapped = true
  n = a.size
  j = 0
  while swapped do
    swapped = false
    j += 1
    (n - j).times do |i|
      if a[i] > a[i + 1]
        a[i], a[i + 1] = a[i + 1], a[i]
        swapped = true
      end
    end
  end
  a
end

class TestBubbleSort < Test::Unit::TestCase
  def test_sort
    arr = sort([6,3,5,2])
    assert_operator arr[0], :<, arr[1]
    assert_operator arr[2], :<, arr[3]
  end
end