Playing around with sidekiq workers and dependency injection. You cannot create a new instance of the worker with dependencies injected and call `perform_async` on the instance. (This doesn't make much sense now that I've grasped how sidekiq works, but would have been nice). But you can achieve something similar using a factory to build the depe…

dispatcher.rb

require_relative 'worker'

class Dispatcher
  def self.dispatch_instance
    Worker.new(STDOUT).perform_async('This is working')
  end

  def self.dispatch_class
    Worker.perform_async('This is working')
  end
end

begin
  Dispatcher.dispatch_class
rescue => e
  STDERR.puts "Dispatching async worker via class failed: #{e.message}"
end

begin
  Dispatcher.dispatch_instance
rescue => e
  STDERR.puts "Dispatching async worker via instance failed: #{e.message}"
end

factory.rb

module Factory
  def self.outputer
    STDOUT
  end
end

worker.rb

require 'sidekiq'
require_relative 'factory'

class Worker
  include Sidekiq::Worker

  def initialize(outputer = Factory.outputer)
    @outputer = outputer
  end

  def perform(output)
    @outputer.puts('*'*80)
    @outputer.puts(output)
    @outputer.puts('*'*80)
  end
end

worker_test.rb

require 'minitest/autorun'
require 'minitest/spec'
require 'minitest/mock'

require_relative 'lib/worker'

require 'sidekiq/testing'

describe Worker do
  it 'uses the outputer to output the message' do
    outputer = MiniTest::Mock.new
    worker = Worker.new(outputer)

    message = 'irrelevant message'
    outputer.expect(:puts, nil, ['*'*80])
    outputer.expect(:puts, nil, [message])
    outputer.expect(:puts, nil, ['*'*80])
    worker.perform(message)

    outputer.verify
  end
end