Some helpers for interactive with jQuery UI from Capybara, but only when using Selenium WebDriver.

capybara-jquery_ui.rb

require "capybara"

# Encapsulate some jQuery UI interactions so we can call them cleanly using Capybara.
module Capybara::JQueryUI
  # Find the jQuery UI Autocomplete widget corresponding to this element
  def autocompleter
    jquery_result(jquery_this(".autocomplete('widget')").first)
  end

  # Fill in an autocompletable field and accept a completion.
  #
  # If you've pre-filled, select the first autocompletion result with:
  #
  #   autocomplete("field name")
  #
  # but you can also do the whole lot in a single call:
  #
  #   autocomplete("Author", with: "jac", text: "Jackie", exact: false)
  #
  def autocomplete field, options={}
    options, field = field, nil if field.is_a? Hash
    if field
      find_field(field).autocomplete(options)
    else
      set(options.delete(:with)) if options[:with]

      jquery_this(%{.autocomplete("search")})

      if options.empty?
        autocompleter.find("li:first-of-type a").click
      else
        autocompleter.find("li a", options).click
      end
    end
  end

  # Find the jQuery UI Datepicker widget corresponding to this element
  def datepicker
    jquery_result(jquery_this(".datepicker('widget')").first)
  end

  # Pick a date from a jQuery UI Datepicker
  #
  #   datepick 2.days.from_now, from: "Deadline"
  #
  # Note that per http://api.jqueryui.com/datepicker/#method-setDate you
  # can use a relative date string, like "+1d"
  def datepick date, options={}
    if options[:from]
      find_field(options.delete(:from)).datepick(date, options)
    else
      date_and_or_time_pick date, "datepicker", options
    end
  end

  # Find the jQuery UI Datetimepicker widget corresponding to this element
  def datetimepicker
    jquery_result(jquery_this(".datetimepicker('widget')").first)
  end

  # Pick a date and time from a jQuery UI Datetimepicker
  #
  #   datetimepick 2.days.from_now, from: "Deadline"
  #
  def datetimepick datetime, options={}
    if options[:from]
      find_field(options.delete(:from)).datetimepick(datetime, options)
    else
      date_and_or_time_pick datetime, "datetimepicker", options
    end
  end

  # Find the jQuery UI Timepicker widget corresponding to this element
  def timepicker
    jquery_result(jquery_this(".timepicker('widget')").first)
  end

  # Pick a time from a jQuery UI Timepicker
  #
  #   timepick "12:00pm", from: "Deadline"
  #
  def timepick time, options={}
    if options[:from]
      find_field(options.delete(:from)).timepick(time, options)
    else
      date_and_or_time_pick time, "timepicker", options
    end
  end

private

  def date_and_or_time_pick date_and_or_time, widget, options={}
    synchronize do
      # Javascript dates are awful, use the millisecond representation for fidelity.
      js_value = if date_and_or_time.is_a? Date or date_and_or_time.is_a? Time
        "new Date(#{date_and_or_time.to_i * 1000})"
      else
        date_and_or_time.to_json
      end

      click

      jquery_this(%{.#{widget}("setDate", #{js_value})})
    end
  end

  # Execute some javascript essentially starting with "$(this)" ...
  #
  # You can also pass arguments which will be JSON round-tripped and
  # accessable in your javascript starting with `arguments[1]`.
  #
  # Please only use this to construct strong ruby encapsulations of jquery
  # actions within this module.
  def jquery_this dot_something, *args
    # From https://code.google.com/p/selenium/wiki/JsonWireProtocol#POST_/session/:sessionId/execute
    # Arguments may be any JSON-primitive, array, or JSON object. JSON objects
    # that define a WebElement reference will be converted to the corresponding
    # DOM element. Likewise, any WebElements in the script result will be
    # returned to the client as WebElement JSON objects.
    session.driver.browser.execute_script %{return $(arguments[0])#{dot_something}}, self.native, *args
  end

  # Script evaluations can yield selenium nodes. We need to wrap them in a
  # capybara node so we can call capybara actions on them.
  def wrap_selenium_node element
    Capybara::Node::Base.new(session, Capybara::Selenium::Node.new(session.driver, element))
  end
end

# The actions are included into Capybara's Node class so nodes traversed
# through Capybara's API can utilise the jQuery UI actions just like they
# use `click`, `set`, etc.
class Capybara::Node::Base
  include Capybara::JQueryUI
end

# The Capybara DSL is included into rspec's ExampleGroups so these methods
# can be used in spec bodies. They just delegate to the page, which is the
# default Capybara::Session.
module Capybara::DSL
  delegate :autocomplete, :datepick, :datetimepick, :timepick, to: :page
end

# ... and the session delegates the actions to the current_scope, which is
# always a Node, starting as the whole HTML document and being modified by
# `within` calls.
class Capybara::Session
  delegate :autocomplete, :datepick, :datetimepick, :timepick, to: :current_scope
end

I think this should be released as a gem. What do you think?