Rails model test - should_receive method not working - ruby-on-rails

Question

I'm writing a pretty straightforward method. Whenever a referer has referred 5 people to become new users, I want them to get a refund. This means that when a new user is created, there's a method check_referer that checks to see if the person who referred them (if this person exists) should get a refund because they've now referred 5 people in total.
In the test logs, based on the puts statement, I can tell that the code is working and the refund_membership_fees_paid method is indeed being called once. But the test keeps failing with:
Failure/Error: #referer.should_receive(:refund_membership_fees_paid).exactly(1).times
(#<User:0x007fbf46bf1c58>).refund_membership_fees_paid(any args)
expected: 1 time with any arguments
received: 0 times with any arguments
Test code:
describe User, "Test refund_membership_fees_paid method is called" do
before do
#referer = User.new()
#referer.save(validate:false)
RefererRefundAlert.stub_chain(:new, :async, :perform)
end
it "at 5 users" do
5.times do |index|
u = User.new(referred_by: #referer.id)
u.save(validate:false)
end
#referer.should_receive(:refund_membership_fees_paid).exactly(1).times
end
end
Model code:
def check_referer
if self.referred_by.present? && User.where(referred_by: self.referred_by).count == 5
User.find(self.referred_by).refund_membership_fees_paid
end
end
def refund_membership_fees_paid
puts "refund_membership_fees_paid method"
RefererRefundAlert.new.async.perform(self.id)
end

Answer 1

User.find does not return the same object as #referer; it will return a different instance of User that represents the same user in the database.
Instead of checking whether refund_membership_fees_paid is called, you can verify that the correct user ID is getting passed intoRefererRefundAlert.new.async.perform.
Also, as others mentioned, you should set your expectation before running the tested methods.
RefererRefundAlert.new.async.should_receive(:perform)
.with(#referer.id).exactly(1).times
5.times do |index|
u = User.new(referred_by: #referer.id)
u.save(validate:false)
end

Answer 2

The use of should_receive is to set the expectation for the following action.
For example, if your account.close action is supposed to log the closure, the test would be...
logger.should_receive(:account_closed)
account.close
So your example should be restructured to put the test first...
#referer.should_receive(:refund_membership_fees_paid).exactly(1).times
5.times {User.new(referred_by: #referer.id).save(validate: false)}