date_helpers.rb

module DateHelpers
  DATE_TIME_SUFFIXES = {
    :year   => '1i',
    :month  => '2i',
    :day    => '3i',
    :hour   => '4i',
    :minute => '5i'
  }

  def select_date(date_to_select, options ={})
    date = date_to_select.is_a?(Date) || date_to_select.is_a?(Time) ?
              date_to_select : Chronic.parse(date_to_select)

    id_prefix = id_prefix_for(options)

    select date.year.to_s, :from => "#{id_prefix}_#{DATE_TIME_SUFFIXES[:year]}"
    select date.strftime('%B'), :from => "#{id_prefix}_#{DATE_TIME_SUFFIXES[:month]}"
    select date.day.to_s, :from => "#{id_prefix}_#{DATE_TIME_SUFFIXES[:day]}"
  end

  def id_prefix_for(options = {})
    msg = "cannot select option, no select box with id, name, or label '#{options[:from]}' found"
    locate(:xpath, Capybara::XPath.select(options[:from]), msg)['id'].gsub(/_#{DATE_TIME_SUFFIXES[:year]}$/,'')
  end
  
  def doc_table_diff(expected_table)
    doc = Nokogiri::HTML(page.body)
    actual_table = []
    yield doc, actual_table
    expected_table.diff!(Cucumber::Ast::Table.new(actual_table))
  end
  
  def flatten_children(node)
    return [] if node.nil?
    
    children = node.children.to_a
    return [node.content] if children.empty?
    
    children.map { |c| flatten_children(c) }.flatten
  end
end

World(DateHelpers)

date_steps.rb

When /^(?:|I )select "([^\"]*)" as the "([^\"]*)" date$/ do |date, date_label|
  select_date(date, :from => date_label)
end