Help needed: upgrading from Rails 2.0.2 to Rails 2.3.5

Hi,

I am trying to upgrade my existing application from Rails 2.0.2 to
2.3.5. I am getting the following error while I run the test:

ruby test/unit/address_test.rb --name test_address2_required_in_jp

Loaded suite test/unit/address_test
Started
E
Finished in 0.001887 seconds.

  1) Error:
test_address2_required_in_jp(AddressTest):
NoMethodError: You have a nil object when you didn't expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.[]
    test/unit/address_test.rb:195:in `test_address2_required_in_jp'
    test/test_helper.rb:134:in `run'

In 195th line I just used a fixture like addresses(:jp_address) which
worked well before rails upgrading.

Thanks,
Arun