Testing
BigQuery pipelines are notoriously hard to test because every query costs money and requires live infrastructure. This guide covers three layers of testing: bq-test-kit for Python unit tests against a local emulator, dbt's built-in test framework for data quality assertions, and direct SQL testing patterns for UDFs and
Testing
Testing tRPC hooks means testing React Query hooks — and that means dealing with providers, async state transitions, and cache behavior. This post covers how to set up a minimal tRPC + QueryClient test wrapper, how to test loading, error, and success states with React Testing Library, how to verify optimistic updates
Testing
tRPC's createCaller() lets you call router procedures directly in tests — no HTTP server, no fetch mocking, no supertest. You inject the context (auth session, database client) yourself, which means you can test authenticated and unauthenticated flows, input validation, middleware enforcement, and error handling with plain function calls. This
Testing
The failure modes of SQS, SNS, and EventBridge are well-known: duplicate delivery, out-of-order messages, poison pills that fill DLQs, and missing idempotency guards that corrupt state. This post covers the testing patterns that catch these bugs before they reach production. Key Takeaways Test idempotency explicitly. SQS delivers messages at least
Testing
Authentication bugs are some of the most costly bugs to ship. Testing fastify-jwt means verifying that protected routes reject unauthenticated requests, that expired tokens fail gracefully, that the refresh flow issues new tokens correctly, and that RBAC rules enforce role boundaries. This post covers all four, with test patterns you
Testing
Combining Fastify with TypeScript and Zod gives you end-to-end type safety from the HTTP layer down to your database. But that safety only holds if you test it. This post covers how to verify that Zod schemas reject malformed requests, how to assert on validation error shapes, and how to
Testing
moto is great for unit tests but stops at service boundaries. When you need SQS triggering Lambda, SNS fan-out to multiple SQS queues, or Lambda updating DynamoDB — you need LocalStack. This guide sets up a full LocalStack integration test environment with Docker Compose, pytest fixtures, and reusable infrastructure helpers. Key
Testing
Fastify's plugin system is one of its best features — and one of the trickier things to test properly. This post covers how to use inject() for in-process route testing, how to verify lifecycle hooks fire in the right order, and how to assert that decorators are registered and
Testing
EventBridge is AWS's serverless event bus. Testing it means verifying that events match the right rules, rules route to the right targets, schemas validate correctly, and cross-bus or cross-account flows work as expected. moto supports EventBridge for unit tests; LocalStack handles the full cross-service integration. Key Takeaways Test
Testing
Apache Pulsar Functions are lightweight compute units that transform or route messages — they're easy to unit-test because the Pulsar team provides a MockContext that eliminates the broker dependency. Stateful functions need state store tests. Multi-tenant applications need namespace isolation tests. Schema evolution tests prevent production data pipeline breaks.
Testing
NATS JetStream persistence introduces durable consumers, sequence-based message tracking, and stream retention policies. Testing these means verifying that a consumer resumes exactly where it left off after restart, that exactly-once deduplication works, and that your stream retention policy doesn't silently discard messages your consumers haven't read
Testing
SNS is a pub/sub service where one publisher sends to a topic and multiple subscribers receive. Testing SNS means verifying: messages reach the right subscribers, message filters work correctly, delivery failures go to the DLQ, and fan-out to SQS queues behaves as expected. moto handles all of this in-process