How do I test Express.js middleware?

What is the best way to test middleware in an Express.js application?

The best way to test middleware in Express.js is to use a testing framework like Mocha or Jest along with Supertest.

Can you give me an example of how to set up a test for middleware?

Sure! You can create a test file where you import your middleware and use Supertest to simulate requests.

What should I include in my middleware tests?

Include tests for the expected behavior, such as checking response status, headers, and any modifications to the request or response objects.

Are there any common pitfalls to avoid when testing middleware?

Yes, avoid testing implementation details and focus on the behavior of the middleware. Also, ensure to clean up after tests.