test: add integration and e2e test for requiring CJS .js module in serverless runtime

Author: pieh

tests/e2e/simple-app.test.ts

@@ -252,3 +252,14 @@ test('Compressed rewrites are readable', async ({ simple }) => {
   expect(resp.headers.get('content-encoding')).toEqual('br')
   expect(await resp.text()).toContain('<title>Example Domain</title>')
 })
+
+test('can require CJS module that is not bundled', async ({ simple }) => {
+  const resp = await fetch(`${simple.url}/api/cjs-file-with-js-extension`)
+
+  expect(resp.status).toBe(200)
+
+  const parsedBody = await resp.json()
+
+  expect(parsedBody.notBundledCJSModule.isBundled).toEqual(false)
+  expect(parsedBody.bundledCJSModule.isBundled).toEqual(true)
+})

tests/fixtures/simple/app/api/cjs-file-with-js-extension/bundled.cjs

@@ -0,0 +1,9 @@
+const { parse: pathParse } = require('node:path')
+
+const fileBase = pathParse(__filename).base
+
+module.exports = {
+  fileBase,
+  // if fileBase is not the same as this module name, it was bundled
+  isBundled: fileBase !== 'bundled.cjs',
+}

tests/fixtures/simple/app/api/cjs-file-with-js-extension/route.js

@@ -0,0 +1,11 @@
+import { NextResponse } from 'next/server'
+import { resolve } from 'node:path'
+
+export async function GET() {
+  return NextResponse.json({
+    notBundledCJSModule: __non_webpack_require__(resolve('./cjs-file-with-js-extension.js')),
+    bundledCJSModule: require('./bundled.cjs'),
+  })
+}
+
+export const dynamic = 'force-dynamic'

tests/fixtures/simple/cjs-file-with-js-extension.js

@@ -0,0 +1,9 @@
+const { parse: pathParse } = require('node:path')
+
+const fileBase = pathParse(__filename).base
+
+module.exports = {
+  fileBase,
+  // if fileBase is not the same as this module name, it was bundled
+  isBundled: fileBase !== 'cjs-file-with-js-extension.js',
+}

tests/integration/simple-app.test.ts

@@ -245,6 +245,20 @@ test.skipIf(process.env.NEXT_VERSION !== 'canary')<FixtureTestContext>(
   },
 )
 
+test<FixtureTestContext>('can require CJS module that is not bundled', async (ctx) => {
+  await createFixture('simple', ctx)
+  await runPlugin(ctx)
+
+  const response = await invokeFunction(ctx, { url: '/api/cjs-file-with-js-extension' })
+
+  expect(response.statusCode).toBe(200)
+
+  const parsedBody = JSON.parse(response.body)
+
+  expect(parsedBody.notBundledCJSModule.isBundled).toEqual(false)
+  expect(parsedBody.bundledCJSModule.isBundled).toEqual(true)
+})
+
 describe('next patching', async () => {
   const { cp: originalCp, appendFile } = (await vi.importActual(
     'node:fs/promises',