How can I run cucumber along with selenium and capybara on a machine without a browser?
Yes there is a simple way to run firefox in headless if you're running linux/mac. You can achieve this by using Xvfb standard xwindow utility. There is a gem that wraps it into ruby utility class headless
I've tried several headless browsers - Culerity, Akephalos, Capybara-Webkit for running tests against our (javascript-heavy) application.
All of them resulted in errors that did not occur when the same tests were run in a real browser - so I will second the advice above: your best bet is to get a browser installed and run it in Xvfb.
There is HTMLUnitDriver which is completly headless - http://selenium.googlecode.com/svn/trunk/docs/api/java/org/openqa/selenium/htmlunit/HtmlUnitDriver.html