cash_out.feature

  Scenario: Attempt to cash out less than the available balance
    Given I am signed in as a complete member
    And I have $25.50 in cash
    When I follow "Redeem"
    And I fill in the Amazon gift card amount field with "25"
    And I press "Redeem"
    Then I should see error messages

field_by_selector_locator.rb

# in features/support

require "webrat/core/locators/locator"

# Lets you find a Webrat::Field via a CSS selector
module Webrat
  module Locators

    class FieldBySelectorLocator < Locator # :nodoc:

      def locate
        Field.load(@session, field_element)
      end

      def field_element
        @dom.at(@value)
      end

      def error_message
        "Could not find field with selector #{@value.inspect}"
      end

    end

    def field_by_selector(selector, *field_types)
      FieldBySelectorLocator.new(@session, dom, selector, *field_types).locate!
    end

  end

  class Session
    def_delegators :current_scope, :field_by_selector
  end

  module Methods
    delegate_to_session :field_by_selector
  end
end

named_element_steps.rb

# in features/step_definitions

When /^(?:|I )fill in ([^"].*) with "([^\"]*)"$/ do |named_element, value|
  field = field_by_selector(selector_for(named_element))
  fill_in(field, :with => value)
end

named_elements.rb

# in features/support

module NamedElements
  # Accepts a named element (such as "the user info area") and returns a
  # selector to find that element on the page (such as "#user-info").
  def selector_for(named_element)
    case named_element
    when /Amazon gift card amount/i
      'input#cash_out_amazon_giftcard_amount'

      # Add more named elements here
    else
      raise %{No selector defined for an element with name "#{named_element}"\n} +
            "Check out features/support/named_elements.rb and add one"
    end
  end
end

World(NamedElements)