Testing

What a test actually verifies, why the testing pyramid has the shape it does, and how runners, assertion libraries, and test doubles fit together - the mental model behind every other page in this section.

Learn testing basics for Node.js APIs, including the testing pyramid, unit tests with node:test, and HTTP integration tests with Supertest.

Learn to use Node.js's built-in node:test runner and node:assert module for zero-dependency unit testing of backend logic.

Learn to set up Vitest for fast TypeScript testing in Node.js, including watch mode, mocking external APIs, and configuring coverage thresholds.

Test Express and Fastify apps with Supertest by sending HTTP requests in-process, avoiding port binding for fast, parallel-safe integration tests.

Learn best practices for Node.js API testing, including how to test behavior, not implementation, and isolate databases per CI job or suite.

A single-page roundup of every highlight bullet from the 10 pages in the Testing section, grouped by source page so you can scan all 58 takeaways without opening each article individually.