Question

I have a ‘Cost’ model in rails. Something like the following:

class Cost < ActiveRecord::Base

    belongs_to :cost_type
    has_many :cost_distributions

    attr_accessor :epp

    def initialize()
    end

However, in my tests, when I try to create new instance with the empty constructor

    cost = Cost.new

I get an error: wrong number of arguments (0 for 1). Why is it ignoring my empty constructor?

Answer 1

You need to allow ActiveRecord to do its own initialization since you are essentially overriding the behavior. Just change your initialize to this:

def initialize()
 super
end

However, if you don’t supply a constructor at all, Rails lets you create the model without parameters:

Cost.new

So is your empty initialize method doing anything else? If not, its not even needed.