My attempt at a solution

Haven't yet written the command line interface but the core functionality (generating the statistic) is there.

I had a hard time figuring out where to start with the testing. I kept thinking that my tests should tell me if I counted the right number of lines or not. And since I didn't know the those numbers I found it hard to get started.
So I looked at how other people had solved it and I got inspired by how @andyw8 had done [his testing](https://github.com/andyw8/shakespeare_analyzer/blob/master/spec/shakespeare_analyser_spec.rb) so I stole his approach and came up with a solution.