An RSpec test that ensure that the Sidekiq worker can actually boot without crashing, and runs a real test job from Redis

sidekiq_health_check_job.rb

# frozen_string_literal: true

# spec/jobs/worker_health_check_job_spec.rb starts a Sidekiq worker process
# and checks stdout for some expected strings. This ensures that Sidekiq
# can boot without crashing, and run a real job from a Redis queue.

class SidekiqHealthCheckJob
  include Sidekiq::Worker

  def perform(string)
    puts "[SidekiqHealthCheckJob] => #{string}"
  end
end

sidekiq_health_check_job_spec.rb

# frozen_string_literal: true

RSpec.describe SidekiqHealthCheckJob do
  before(:each) do
    Sidekiq::Testing.disable!
  end

  it 'starts a Sidekiq worker process and performs SidekiqHealthCheckJob' do
    require 'pty'
    random_string = SecureRandom.hex(32)
    jid = SidekiqHealthCheckJob.perform_async(random_string)

    sidekiq_output = []
    match_index = 0
    output_expectations = [
      /SidekiqHealthCheckJob JID-#{jid} INFO: start/,
      /\[SidekiqHealthCheckJob\] => #{random_string}/,
      /SidekiqHealthCheckJob JID-#{jid} INFO: done/,
    ]
    begin
      Timeout.timeout(60) do
        begin
          PTY.spawn('sidekiq 2>&1') do |reader, _, pid|
            reader.each_line do |line|
              sidekiq_output << line
              next unless line.match?(output_expectations[match_index])

              match_index += 1
              next unless match_index == output_expectations.size

              Process.kill(9, pid)
            end
          end
        rescue Errno::EIO
          nil
        end

        expect(match_index).to(
          eq(output_expectations.size),
          "Matches: #{match_index}, Output:\n#{sidekiq_output.join('')}"
        )
      end
    rescue Timeout::Error
      raise Timeout::Error, 'Sidekiq output did not match expectations! ' \
        "Output:\n#{sidekiq_output.join('')}"
    end
  end
end