Node.js Testing Best Practices

This repository narrows the testing lens to Node.js backends, focusing on the challenges of servers, microservices, and cloud-native deployments. It covers API testing, contract testing, and persistence-layer strategies that avoid coupling tests to fragile implementation details. The material explains how to structure tests around process boundaries—HTTP, queues, cron jobs—while keeping fast feedback cycles through selective integration tests and reliable test doubles. It dives into topics like test containers, ephemeral databases, and idempotent fixtures to ensure deterministic runs in CI. Observability is treated as part of testing: logs, metrics, and tracing make failures diagnosable instead of mysterious. By aligning tests with service responsibilities instead of internal modules, the guide helps teams produce suites that reflect real production behavior.