Node.js Express RESTful API Unit Testing with Supertest and Jest

Reliable software requires rigorous testing. In the Node.js ecosystem, Jest and Supertest form a powerful combination for testing RESTful APIs without needing to spin up a live server.

What is Covered?

In this article, I demonstrate how to write integration tests for your API endpoints.

1. Setting up the Test Environment: Configuring Jest for a Node.js project.
2. Supertest Basics: How to simulate HTTP requests (GET, POST, PUT, DELETE) against your Express app.
3. Assertions: Verifying response status codes, headers, and JSON bodies.
4. Mocking: Tips for isolating your tests from external dependencies (databases, third-party services).

Testing is not just about finding bugs; it's about documenting how your API is expected to behave and allowing you to refactor with confidence.

Read the Full Guide

For the full code examples and step-by-step tutorial, check out the article on Medium.

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