module Shoulda::Matchers::ActiveModel::Helpers

def default_error_message(type, options = {})
  model_name = options.delete(:model_name)
  attribute = options.delete(:attribute)
  instance = options.delete(:instance)
  RailsShim.generate_validation_message(
    instance,
    attribute.to_sym,
    type,
    model_name,
    options,
  )
end

def format_validation_errors(errors)
  list_items = errors.to_hash.keys.map do |attribute|
    messages = errors[attribute]
    "* #{attribute}: #{messages}"
  end
  list_items.join("\n")
end

def pretty_error_messages(object)
  format_validation_errors(object.errors)
end