Overriding initialize error test environment - ruby-on-rails

Question

I am having a hard time understanding an error with ruby's open classes. Overriding a method in test environment (rails) causes an invalid arguments error on initialize. For some reason, overriding the new method solved the problem. Why?
My class:
require 'adwords_api'
require 'adwords_config'
require 'scanf'
class AdwordsHelper
attr_accessor :adwords_id
attr_accessor :campaign_id
attr_accessor :adgroup_id
attr_accessor :invalid_ops
##RETRY_INTERVAL = 3
##RETRIES_COUNT = 500
##config = 'adwords_api.yml'
def initialize(args = {})
self.adwords_id = AdwordsConfig.config[:master_account]
return unless args.is_a?(Hash)
args.each do |k,v|
instance_variable_set("##{k}", v) unless v.nil?
end
end
def set_budget(budget)
#api = get_adwords_api
budget_id = get_budget_id
service = #api.service(:BudgetService)
operation = {
:operator => 'SET',
:operand => {
:budget_id => budget_id,
:amount => {
:micro_amount => budget
}
}
}
service.mutate([operation])
end
end
Now in the test, I want to override one of the methods, because I don't want there to be communication with the actual adwords servers.
require "test_helper"
# FIXME override this in another file eventually
class AdwordsHelper
def set_budget(budget)
true
end
end
Calling
AdwordsHelper.new(campaign_id: 1)
gives an invalid arguments 1 for 0 error.
Now, overriding the new function, solves the error.
class AdwordsHelper
def self.new(*args, &block)
obj = allocate
obj
end
def set_budget(budget)
true
end
end
Is overriding the method set_budget causing other quirks?

Answer 1

Try
AdwordHelper.class_eval do
def set_budget(budget)
true
end
end
class AdwordHelper will define the class when the original AdwordHelper is not loaded already, in which case the only method that exists in your class is set_budget. It wouldn't know about the initialize with one argument.
Whereas, if you use class_eval, it tries to load the file containing AdwordHelper class and then add the method set_budget to the class.