Poltergeist is a driver for Capybara. It allows you to run your Capybara tests on a headless PhantomJS browser. If you would like to run your tests on headless Chrome there's another project Cuprite ...
This component is not maintained anymore. I have an installation issue I can't seem to resolve... I've reached out to multiple communities and devs and still had no joy. Besides, the phantomjs v2.5 ...