gistfile1

require 'rubygems'
require 'spec'

include Spec::Matchers

a = (1..10).to_a
b = (5..15).to_a

matcher = MatchArray.new(a)
matcher.matches?(b) # => false

print matcher.failure_message_for_should  

# Output:
# expected collection contained:  [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
# actual collection contained:    [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
# the missing elements were:      [1, 2, 3, 4]
# the extra elements were:        [11, 12, 13, 14, 15]