Are you saying that is what you want to get? This is what I get.

irb(main):004:0> index << {:test => { :test1 => "hola", :test2=> 23}}
=> nil
irb(main):005:0> index[0][:test]
=> "test1holatest223"

To get what you have I would have to do this;

irb(main):006:0> index << {:test => { :test1 => "hola", :test2=> 23}.inspect}
=> nil
irb(main):007:0> index[1][:test]
=> "{:test1=>\"hola\", :test2=>23}"

If this is what you want, it shouldn't be too hard to write a wrapper to do this. I don't really think it is an issue though.