Add tree-shaking test with eval

test/integration/middleware/core/lib/utils.js

@@ -0,0 +1,8 @@
+export function getTextWithEval() {
+  // eslint-disable-next-line no-eval
+  return eval('with some text')
+}
+
+export function getText() {
+  return 'with some text'
+}

test/integration/middleware/core/pages/responses/_middleware.js

@@ -1,6 +1,7 @@
 import { createElement } from 'react'
 import { renderToString } from 'react-dom/server.browser'
 import { NextResponse } from 'next/server'
+import { getText } from '../../lib/utils'
 
 export async function middleware(request, ev) {
   // eslint-disable-next-line no-undef
@@ -36,7 +37,8 @@ export async function middleware(request, ev) {
     ev.waitUntil(
       (async () => {
         writer.write(encoder.encode('this is a streamed '))
-        writer.write(encoder.encode('response'))
+        writer.write(encoder.encode('response '))
+        writer.write(encoder.encode(getText()))
         writer.close()
       })()
     )

test/integration/middleware/core/test/index.test.js

@@ -254,7 +254,7 @@ function responseTests(locale = '') {
       `${locale}/responses/stream-a-response`
     )
     const html = await res.text()
-    expect(html).toBe('this is a streamed response')
+    expect(html).toBe('this is a streamed response with some text')
   })
 
   it(`${locale} should respond with a body`, async () => {