testing references

I am struggling somewhat with testing. And I would like to know a
comprehensive reference on rails unit test. I find the railscasts 5
minute video not comprehensive. I have the ruby programming language,
design patterns in ruby, and rails 3 way books and none of them delve
at all into testing. So I am curious what everyone else is using as
their testing reference.

This helped me understand syntax and strategy.

http://www.codeschool.com/courses/testing-with-rspec