React
Loaders and actions in React Router v7 are plain async functions. Testing them directly — without rendering any component — gives you fast, reliable, and surgical feedback. This post covers every scenario: happy paths, error responses, redirects, validation failures, and async mocking patterns using Vitest. Key Takeaways Test loaders and actions as
Tools & Frameworks
fast-check is the leading property-based testing library for JavaScript and TypeScript. It brings Haskell's QuickCheck model to the JS ecosystem with full TypeScript types, a rich built-in arbitrary library, model-based testing for stateful systems, and seamless integration with Jest, Vitest, and Mocha. Key Takeaways
Testing Strategy
When a test fails in a distributed system, the error message tells you what failed — not where, why, or which of the twelve services involved was responsible. Distributed tracing in your test suite gives you the full execution path for every test run, turning hours of log-digging into a
Tools & Frameworks
Hypothesis is Python's most powerful property-based testing library. It extends pytest with the @given decorator and a rich strategy API so you can describe the shape of your inputs rather than specific values. Hypothesis then generates hundreds of examples, finds failures, and shrinks them to the minimal
React
React Router v7 unified the React Router and Remix libraries into one package, introducing routes.ts, framework mode SSR, and new testing APIs. This guide covers how to test every layer of a v7 app — from individual loaders to full E2E flows — using Vitest, React Testing Library, and Playwright. Key
api-testing
Webhook handlers are business-critical but rarely tested systematically. This guide shows how to build a complete webhook testing pyramid in CI/CD: unit tests for handler logic, smee.io integration tests, contract tests with JSON Schema, security tests for signature verification, and Toxiproxy for retry behavior. Full pytest and
api-testing
Svix is managed webhook sending infrastructure — it handles delivery, retries, signatures, and consumer dashboards for SaaS applications that need to send webhooks to their customers. This guide covers testing Svix webhook delivery in your app, using Svix's SDK for signature verification, testing consumer endpoints, and when to use
api-testing
Hookdeck is a webhook gateway and event queue that sits between your webhook senders and your application. It gives you a request inspector for debugging payloads, event replay for development, and filtering and transformation as middleware. This guide walks through setting up Hookdeck CLI for local development, using the dashboard
api-testing
Webhooks are notoriously hard to test because they're triggered by external events, delivered asynchronously, and come with failure modes like duplicate delivery, out-of-order events, and retry storms. This guide covers five testing strategies, plus how to test idempotency, retry logic, signature verification, and failure scenarios with
Compliance Testing
EU AI Act compliance for high-risk AI systems is not a one-time checklist — it requires ongoing automated testing. This guide shows how to integrate bias, accuracy, robustness, audit trail, and logging tests into GitHub Actions using DeepEval and Giskard, with full YAML examples and a production monitoring setup
AI Testing
LLMs encode the biases present in their training data — and those biases surface in completions in ways that are measurable and testable. This guide covers what LLM bias looks like in practice, how to measure it with established benchmarks and DeepEval, how to build a bias test suite, and how
AI Testing
AI systems fail in ways traditional software doesn't — they drift, discriminate, and hallucinate, often silently. Risk-based testing for AI means probing bias across demographic groups, benchmarking accuracy under distribution shift, testing adversarial robustness, and measuring hallucination rates. This guide shows how to do all of it with