From: Timo Hoepfner <th-dev@...>
Date: 2005-12-12T17:08:10+09:00
Subject: Strange bahaviour of "Set"

Hi,

I already mentioned this in another thread, but I think this is of  
general interest. So sorry, if you read it twice.

While working on something involving the "Set" class of the Ruby  
standard library, I came across the following:

require "set"
require "test/unit"

class TestSet < Test::Unit::TestCase

   def test_set
     array_of_arrays=[["a", "b"]]
     array_of_sets=array_of_arrays.map{|an_array| an_array.to_set}
     set_of_sets=array_of_sets.to_set
     contained_array=["a","b"]
     contained_set=contained_array.to_set
     # OK
     assert_equal(true, array_of_arrays.include?(contained_array))
     # OK
     assert_equal(true, array_of_sets.include?(contained_set))
     # fails
     assert_equal(true, set_of_sets.include?(contained_set))
   end
end

The third assertion fails. Is this intended behaviour?

Timo