when i use rspec with capybara to test my rails js page , I got the following error: "Selenium::WebDriver::Error::WebDriverError: Could not find Firefox binary (os=linux). " Actually my rails script are all written on the linux server, where there is on brower installed, and any desktop software is not supported on the server (since no X11 is installed). How can I test js in this situation. Or is there and brower that works without X11 installed like wget? Thanks.