Hello everyone I had a few questions I just downloaded rcov and have
it up my question is are there any good sites that teach you how to
write TDD in rails.
or any books that can teach me the fundamentals of TDD in rails
Rails is all about the TDD - getting a test (or a "spec") to fail first, then writing code to pass the test, then refactoring.
The most important aspect of this is a TDD-friendly editor. You need to _minimize_ the time between changing code and getting test results. That lets you test one edit at a time, which is best.
(And under Ruby you often only _need_ one edit to achieve a testable change, unlike some other languages.)
Don't hold your breath waiting for such an editor...
Read the /Agile Web Development with Rails/ book, by the Daves. It covers TDD as part of the lifecycle (hence the title "Agile") - not as an afterthought.