module Shoulda::Assertions

def assert_same_elements(a1, a2, msg = nil)

assert_same_elements([:a, :b, :c], [:c, :a, :b]) => passes

Asserts that two arrays contain the same elements, the same number of times. Essentially ==, but unordered. 
def assert_same_elements(a1, a2, msg = nil)
  [:select, :inject, :size].each do |m|
    [a1, a2].each {|a| assert_respond_to(a, m, "Are you sure that #{a.inspect} is an array?  It doesn't respond to #{m}.") }
  end
  assert a1h = a1.inject({}) { |h,e| h[e] = a1.select { |i| i == e }.size; h }
  assert a2h = a2.inject({}) { |h,e| h[e] = a2.select { |i| i == e }.size; h }
  assert_equal(a1h, a2h, msg)
end