Make test suite pass on Windows

I'm not certain if easy-file is actually a good dependency to have, but I didn't find anything else on hackage (in my 10 minutes of searching) that would do the proper conversion. It has a few reverse dependencies and files aren't that complicated, so it's probably OK. The other approach is to just hack it out like in 8f04f3366217e3db8f70cfb9839604c833efa1e8, but that seems less clean.