Tests failing on master for MacOS

[carlosms]

For some reason the same code that passed the tests yesterday is failing today.
https://travis-ci.org/src-d/lookout/builds/442659534
https://travis-ci.org/src-d/lookout/builds/443167725

[carlosms]

Tests don't fail anymore. I didn't see anything in the logs, and nothing changed on our side.
I'll close this for now since I can't really reproduce it.