fixtures, how to set a serialized Hash object

I defined in my model :
...
  serialize :unavailables
..

which is set like this (Hash : "year" => 2-dimensional Array)
{"2008" => Array.new(13).map!{ Array.new(32, 1)} }

In my fixture I need to initiliaze this field with the following
hash :

{"2008" => Array.new(4).map!{ Array.new(32, 1)} + Array.new(1).map!
{ [1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] } + Array.new(8).map!
{ Array.new(32, 1)} }

I tried to write :

<%= Hash.new({"2008" => Array.new(10).map!{ Array.new(32, 1)} +
Array.new(1).map!{ [1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] } +
Array.new(2).map!{ Array.new(32, 1)} }) %>
but it gives me a full string :
myobject.unavailables
"200811111111111111111111111111111111111111111111111..."

I also tried :
<%= Hash.new({"2008" => Array.new(10).map!{ Array.new(32, 1)} +
Array.new(1).map!{ [1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] } +
Array.new(2).map!{ Array.new(32, 1)} }).to_yaml %>
but it gives me an empty hash :
myobject.unavailables
{}

any clue ?

thanks

I found a workaround....

I defined a ruby function using irb
def unvailable_period(year, month, day_start, day_end)
     v = {"#{year}" => (Array.new(month).map!{ Array.new(32, 1)} +
Array.new(1).map!{ ( [1] + Array.new(day_end - day_start + 1, -1) +
Array.new(32 - day_end - 1,1) ) } + Array.new(12-month).map!
{ Array.new(32, 1)}) }
end

and i used it to ouput a yaml structure
v = unvailable_period(2008, 10, 1,15)
v.to_yaml
=> "--- \n\"2008\": \n- - 1\n - 1\n - 1\n - 1\n - 1\n - 1\n -
1\n - 1\n - 1\n - 1\n - 1\n - 1\n - 1\n - 1\n - 1\n - 1\n -
1\n - 1\n - 1\n - 1\n - 1\n - 1\n - 1\n ... etc
then I copied/pasted it into my fixture, but it seems to be only a
workaround...

I tried to define the unvailable_period() function into a lib/
unavailable_test_helper.rb ,
and include in my class Test::Unit::TestCase ( test_helper.rb)
but I could not use it from the fixture (error : not found), is
there a way to do it ?

writing in my fixture :
unavailables: <%= unvailable_period(2008, 10, 1,15).to_yaml %>
to get the all structure ?