Mocking an HTTP connection?

Hello, I need to write a class that is able to retrieve several pages
from a web site, examine their content and extract relevants part of
datas.

I am looking for a solution to mock the http connection object during
tests but I did not found many docs about it.

In that case I need to mock a non ActiveRecord object so I wonder how
much it is related with RoR ??

BTW, what is the right way to use the RoR test/mocks/test directories ??

Thanks