Shoulda macro for file_column plugin

should_have_file_column.rb

# file_column Shoulda macro, based off the Paperclip method given here:
# http://giantrobots.thoughtbot.com/2008/3/18/for-attaching-files-use-paperclip#comment--614050918
# pass the extra option :magick => true to test the extra method for the columns that use RMagick
def self.should_have_file_column(attachment, options = {})
  klass = described_type
  fields = ["#{attachment}", "#{attachment}=", "#{attachment}_temp", "#{attachment}_temp=",
     "#{attachment}_dir", "#{attachment}_just_uploaded?", "#{attachment}_options",
     "#{attachment}_relative_dir", "#{attachment}_relative_path"]
  fields << "#{attachment}_magick_after_assign" if options[:magick]
  should "have_file_column #{attachment}" do
    fields.each do |method_name|
       assert klass.instance_methods.include?(method_name), "#{klass.name} does not have a #{method_name} instance method."
    end
  end
end