Wait for jQuery to load before running Capybara tests. http://www.kylev.com/2013/02/17/capybara-synchronize-and-monkeys-that-climb-ivory-towers/

jquery_nonsense.rb

module Capybara
  class Session

    # `execute_script` variant that first waits for jQuery's $ to be defined.
    def execute_jquery(script)
      synchronize_javascript("$ !== 'undefined'")
      execute_script(script)
    end

    # `evaluate_script` variant that first waits for jQuery's $ to be defined.
    def evaluate_jquery(script)
      synchronize_javascript("$ !== 'undefined'")
      evaluate_script(script)
    end

    # Use Capybara's waiting mechanism until a JavaScript expression evaluates to true.
    def synchronize_javascript(script)
      current_node.synchronize do
        raise ExpectationNotMet.new("Script wasn't true") unless evaluate_script(script)
      end
    end

  end
end

Checkout the patiently do ... end block helper from Spreewald. It does something similar, but in a more generic form. Because once you're over this particular problem, you will have fun with asynchronous AJAX calls etc.