Good job on getting tests working for this!

Next challenge: make them run without hitting an external service. If ibiblio.org goes down, your test will fail. Also, these will run slower than they need to.

I'd recommend downloading or creating a small xml fixture and including it in a spec/fixtures directory. Then have your program analyze that for testing.

By the way: making sure your program can swap out details like this (like whether it accepts a url OR a local file) will likely improve its design.