Easily Mock Net::HTTP with Rspec

rspec_mock_net_http.rb

require 'rails_helper'

RSpec.describe MyWorker, type: :job do
  include ActiveJob::TestHelper
  
  let(:sqs_msg) { double AWS::SQS::ReceivedMessage, 
    id: 'fc754df7-9cc2-4c41-96ca-5996a44b771e',
    body: 'test',
    delete: nil }
  
  describe '#perform' do
    
    subject(:job) { described_class.new }

    it 'sends the message' do
      # Setup successful response
      response = Net::HTTPSuccess.new(1.0, '200', 'OK')
      # Setup Net::HTTP to receive the response
      expect_any_instance_of(Net::HTTP).to receive(:request) { response }
      # Setup response to receive follow messages below. 
      # This prevents the elusive "undefined method `close' for nil:NilClass" error.
      expect(response).to receive(:body) { '{"data": "that you want to return"}' }      

      job.perform(sqs_msg)
    end
  end
end