Code caching in development period

Hello!

I make such test:
I have created new RoR-project and have made one controller and on
ruby library:
app/controllers/test_controller.rb
lib/test.rb

I have tested my simple project on 3 web-servers:: thin, mongrel,
apache + passenger in
development-environment.

On all 3 web-servers I see changes in my controller without web-server
restarting.
But changes in test.rb I can see only after web-server restarting.
I understand, why i don't see changes. But I have such questions:

1. Is it possible to configure my web-server or rails so, that require
caching (code caching) for my rb-files was
turned off?
2. Can I by ruby-code reload cached rb-libraries?
3. Can I configure, that web-server doesn't cache all rb-scripts,
except some of them?