CI/CD
Integration tests that hit real databases and message queues are harder to run than unit tests. In GitHub Actions, you configure service containers in YAML and hope they start before your tests run. In Dagger, you define services as code, bind them to your test container, and get the same
Testing
Integration testing for microservices is where good intentions go to die. Teams start with aspirations of comprehensive test coverage across service boundaries, then hit the reality: standing up five services, three databases, a message queue, and a cache just to run a single test is slow, fragile, and expensive to
Testing
Choosing an auth provider is a long-term architectural decision, and your test strategy should make switching providers feasible if your needs change. This guide compares how Clerk, Auth0, and Supabase Auth work in integration tests, and shows how to structure your tests so the auth provider is an implementation detail,
Testing
Unit testing individual pipeline components catches local bugs. But the integration between Kafka, OTel Collector, and your backends is where real failures hide. A schema mismatch between Kafka producer and OTel receiver. A Loki label cardinality issue that only surfaces under load. An OTel Collector exporter that retries forever when
Rust
Integration testing in Rust web applications built with axum is remarkably ergonomic once you understand the tools available. The tower ecosystem that underpins axum gives you direct access to handlers without needing to spin up a real HTTP server, while the axum-test crate provides a higher-level TestClient for tests that
Database Testing
Prisma has become one of the most popular ORMs in the Node.js ecosystem, and for good reason. Its auto-generated TypeScript client, powerful migration system, and intuitive query API make database work genuinely pleasant. But testing Prisma-based applications requires a clear strategy — one that separates fast unit tests from thorough
Database Testing
Drizzle ORM has quickly become a favorite among TypeScript developers who want the type safety of a full ORM without sacrificing raw SQL control. But testing Drizzle-powered applications presents unique challenges: the query builder is deeply integrated with the database driver, transactions span multiple operations, and migrations need to stay
Testing
Every third-party API integration needs tests — but mocking, contract testing, and real integration testing each have different tradeoffs. Mocks are fast but drift from reality. Real integration tests are accurate but slow and expensive. Contract tests are the middle ground that most teams miss. This guide covers when to use
Testing
OAuth2 integrations are painful to test in CI because the authorization code flow requires a browser and human interaction. This guide covers how to test OAuth2 without browser automation: mocking the token exchange, testing the callback handler, validating token storage, testing refresh flows, and running full browser-based auth tests with
Testing
Slack bot testing requires handling signed webhooks, validating Block Kit UI components, testing slash command responses, and simulating event payloads. This guide covers unit testing with mock payloads, integration testing with the Slack SDK's built-in test utilities, and end-to-end testing with Socket Mode. Slack bots have more failure
Testing
SendGrid provides a sandbox mode that validates emails without sending them, dynamic templates you can test independently, and event webhooks for tracking delivery status. This guide covers testing SendGrid integrations at every level: sandbox validation, template rendering, webhook handling, and deliverability simulation. Email bugs are subtle and slow to surface.
Testing
Twilio provides test credentials that accept API calls without sending real messages, specific magic phone numbers for simulating delivery failures, and a webhook testing workflow for voice and SMS. This guide covers unit testing Twilio integrations with mocks, integration testing with test credentials, and testing TwiML responses. Twilio integrations fail