Unable to test middleware with Jest

What version of Next.js are you using?

12.0.7

What version of Node.js are you using?

16.13.1

What browser are you using?

Firefox

What operating system are you using?

Pop!_OS

How are you deploying your application?

Vercel

Describe the Bug

When trying to test _middleware.js with Jest, I’m unable to import { NextResponse } from 'next/server' without throwing an error SyntaxError: Unexpected token 'export' because next/server uses export { NextRequest } in line 1.

Expected Behavior

I would like to be able to test my _middleware.js authentication methodology.

To Reproduce

1. Create a Next app with the aforementioned versions.
2. Create a _middleware.js
3. Create a test for it in Jest.
4. Try to import NextResponse from next/server.
5. Run tests.
6. Get error.

[javivelasco]

We aim to ship very soon a Jest runtime that will allow you to test middleware code without doing anything special. Just a heads up that we are working on this!

[vxcamiloxv]

My solution was create src/__mocks__/next/server.js with the following content, that fixed the issue to me

import { NextRequest } from 'next/dist/server/web/spec-extension/request';
import { NextResponse } from 'next/dist/server/web/spec-extension/response';

export { NextRequest, NextResponse };