How to mock/stub the config initializer hash in rails 3

Question

Environment : Rails 3.1.1 and Rspec 2.10.1 I am loading all my application configuration through an external YAML file. My initializer (config/initializers/load_config.rb) looks like this

AppConfig = YAML.load_file("#{RAILS_ROOT}/config/config.yml")[RAILS_ENV]

And my YAML file sits under config/config.yml

development:
 client_system: SWN
 b2c_agent_number: '10500'
 advocacy_agent_number: 16202
 motorcycle_agent_number: '10400'
 tso_agent_number: '39160'
 feesecure_eligible_months_for_monthly_payments: 1..12

test:
 client_system: SWN
 b2c_agent_number: '10500'
 advocacy_agent_number: 16202
 motorcycle_agent_number: '10400'
 tso_agent_number: '39160'
 feesecure_eligible_months_for_monthly_payments: 1..11

And I access these values as, For example AppConfig['feesecure_eligible_months_for_monthly_payments']

In one of my tests I need AppConfig['feesecure_eligible_months_for_monthly_payments'] to return a different value but am not sure how to accomplish this. I tried the following approach with no luck

describe 'monthly_option_available?' do
 before :each do
  @policy = FeeSecure::Policy.new
  @settlement_breakdown = SettlementBreakdown.new
  @policy.stub(:settlement_breakdown).and_return(@settlement_breakdown)
  @date = Date.today
  Date.should_receive(:today).and_return(@date)
  @config = mock(AppConfig)
  AppConfig.stub(:feesecure_eligible_months_for_monthly_payments).and_return('1..7')
 end
 .....
 end

In my respective class I am doing something like this

class Policy        
 def eligible_month?
  eval(AppConfig['feesecure_eligible_months_for_monthly_payments']).include?(Date.today.month)
 end
....
end

Can someone please point me in the right direction!!

Answer 1

The method that is being called when you do AppConfig['foo'] is the [] method, which takes one argument (the key to retrieve)

Therefore what you could do in your test is

AppConfig.stub(:[]).and_return('1..11')

You can use with to setup different expectations based on the value of the argument, ie

AppConfig.stub(:[]).with('foo').and_return('1..11')
AppConfig.stub(:[]).with('bar').and_return(3)

You don't need to setup a mock AppConfig object - you can stick your stub straight on the 'real' one.