method stubbing on before(:all)

Question

require './spec/spec_helper'
require './bank'

describe Bank do
  context "#transfer" do
    before(:all) do
      @customer1 = Customer.new(500)
      customer2 = Customer.new(0)
      @customer1.stub(:my_money).and_return(1000)
      customer2.stub(:my_money).and_return(0)
      @transfer_message = Bank.new.transfer(@customer1, customer2, 2000)
    end 

    it "should return insufficient balance if transferred amount is greater than balance" do
      expect(@transfer_message).to eq("Insufficient funds")
    end 

    it "calls my_money" do
      expect(@customer1).to have_received(:my_money)
    end 
  end 
end

When I use before(:each) instead before(:all) it works. But if use before(:all) it throws error as undefined method proxy_for for nil:NilClass. I couldn't find out the reason. Could you please help me? Thanks in advance.

Answer 1

Late to the party? Yeah, but wouldn't mind to drop my own one cent from what I discovered. I encountered a similar error while trying to stub a request in a RSpec.configure block so that the stub will only be available to examples I pass the config.around(:each, option) option to.

So, that means I was using the stub outside the scope of individual examples which is not supported by RSpec::Mocks here!. A work around is to use a temporary scope in the context.

So you have

before(:all) do
  RSpec::Mocks.with_temporary_scope do
    @customer1 = Customer.new(500)
    customer2 = Customer.new(0)
    @customer1.stub(:my_money).and_return(1000)
    customer2.stub(:my_money).and_return(0)
    @transfer_message = Bank.new.transfer(@customer1, customer2, 2000)
  end
end

HTH!

Answer 2

before(:all) is not deprecated, but use of doubles from rspec-mocks in before(:all) is not supported. See the referenced issues in github issue for background.

The current master version of rspec-mocks, to be available with 3.0.0.beta2, will fail with the following error:

The use of doubles or partial doubles from rspec-mocks outside of the per-test lifecycle is not supported.

Prior versions will generate the undefined method proxy_for ... error at the point of stubbing.

Answer 3

This should work:

require "rspec/mocks/standalone"
before(:all) do