qa-async-jobs

Adversarial read-only critic for queue and worker code across BullMQ, Celery, Sidekiq, SQS, and RabbitMQ. Scans changed files for four cross-cutting at-least-once reliability defects: missing retry limits, absent dead-letter routing, uncapped or infinite backoff, and missing idempotency guards on handlers. Emits a per-defect findings table and a BLOCK or PASS verdict. Use when reviewing a PR that adds or modifies queue producers, worker processors, job definitions, or broker configuration.

Authors and runs Celery task tests in Python - `pytest-celery` fixtures (`celery_app`, `celery_worker` per-test, `celery_session_worker` per-session); `task_always_eager` config NOT recommended for unit tests; `apply()` for synchronous test invocation; mock-and-patch retry patterns via `unittest.mock.patch` on `task.retry`. Use when the user works with Celery task workers and needs unit / integration tests across function-style or class-style tasks.

Build-an-X for cron / scheduler job tests - cron-expression validation patterns (5-field standard `min hour day-month month day-week` + 6-field with seconds + named-list extensions), DST + leap-day edge cases, missed-execution detection (machine downtime catch-up), overlapping-run protection (lock + stale-lock recovery), timezone semantics. Use when authoring tests for cron jobs, Kubernetes CronJobs, BullMQ repeat-jobs, Sidekiq schedulers, or any time-based job runner.

Build-an-X for idempotency tests in any async/job/API context - idempotency-key handling (per Stripe / AWS prescriptive guidance pattern), retry-safe semantics (exactly-once vs at-least-once vs at-most-once), side-effect commutativity verification, fingerprint-based dedup, idempotency-window tuning. Use when authoring tests for any system where the same input could be processed twice (SQS Standard at-least-once, RabbitMQ requeue, retry-on-error logic, webhook redelivery, browser double-click, mobile-network retry).

Tests Apache Kafka consumer and producer logic across KafkaJS (Node.js), kafka-go (Go), and Spring Kafka (Java) - spins up a real broker via the Testcontainers Kafka module, asserts offset management and consumer-group rebalance behavior, distinguishes at-least-once from exactly-once (EOS / transactions), validates idempotent producer configuration, and routes unprocessable messages to a dead-letter topic. Use when the user works with Kafka producers or consumers in any language and needs integration or unit tests that exercise delivery semantics, offset commits, rebalance handling, or dead-letter routing.

Tests RabbitMQ producer/consumer interactions - supports AMQP 0.9.1 and AMQP 1.0 protocols across 6 tutorial patterns (Hello World, Work Queues, Publish/Subscribe, Routing, Topics, RPC) plus Publisher Confirms; consumer ack/nack/requeue patterns; durable queues + persistent messages; quorum vs classic queue; tests via Testcontainers RabbitMQ image or LocalStack-equivalent. Use when the user works with RabbitMQ producers/consumers (pika, amqplib, RabbitMQ.Client, spring-amqp) and needs unit/integration tests.