should_accept_nested_attributes_for.rb

class Test::Unit::TestCase

  # Assert that the model accepts nested attributes for the given +associations+
  #
  # Example:
  # should_accept_nested_attributes_for :orders
  # 
  def self.should_accept_nested_attributes_for(*associations)
    associations.each do |association|
      should "accept nested attributes for #{association}" do
        assert subject.respond_to?("#{association}_attributes="), "#{subject.class} does not accept nested attributes for association: #{association}"
      end
    end
  end

end