def execute
      return if should_skip?

      print "[#{@runner.step_num}] Verifying display server ... "

      if @runner.is_linux? && !@runner.xvfb_installed?
        return puts "Warning (XVFB is not installed.  Feature specs will fail.)".colorize(:yellow)
      end

      if @runner.is_mac? && @runner.xvfb_installed?
        return puts "Warning (XVFB has been installed.  It's not needed on a Mac and may cause specs to fail.)".colorize(:yellow)
      end

      puts "Success!!".colorize(:green)
    end
def execute
      return if should_skip?

      print "[#{@runner.step_num}] Verifying display server ... "

      if @runner.is_linux? && !@runner.xvfb_installed?
        return puts "Warning (XVFB is not installed.  Feature specs will fail.)".colorize(:yellow)
      end

      if @runner.is_mac? && @runner.xvfb_installed?
        return puts "Warning (XVFB has been installed.  It's not needed on a Mac and may cause specs to fail.)".colorize(:yellow)
      end

      puts "Success!!".colorize(:green)
    end
There are two cases we need to be checked
   1. A Linux user does not have xvfb installed (xvfb is needed to run RSpec feature tests on Linux).
   2. A Mac User has xvfb installed.   (Macs have their own display server so xvfb is not needed; a dev might have mistakenly
      tried to install, so we can check for it just in case.)