class Shoulda::Matchers::ActiveRecord::AssociationMatchers::ModelReflection

def join_table
  join_table =
    if has_and_belongs_to_many_name_table_name
      has_and_belongs_to_many_name_table_name
    elsif reflection.respond_to?(:join_table)
      reflection.join_table
    else
      reflection.options[:join_table]
    end
  join_table.to_s
end