Show HN: webhog – Web scraper written in Go

This is another Go OSS project of mine that I'm using to expand my knowledge of the language and its inner-workings. I'd be extremely interested in gathering advice on the best way to test an application such as this.

Most of the complexity lies within downloading and persisting files - do my test methods need to download physical files from the web as well, or is there a straight-forward way to stub that behavior out? Any feedback is appreciated.