Add test for middleware data prefetch

test/integration/middleware-general/middleware.js

@@ -141,6 +141,11 @@ export async function middleware(request) {
     return NextResponse.next()
   }
 
+  if (url.pathname === '/ssr-page') {
+    url.pathname = '/ssr-page-2'
+    return NextResponse.rewrite(url)
+  }
+
   // Map metadata by default
   return new Response(null, {
     headers: {

test/integration/middleware-general/pages/ssr-page-2.js

@@ -0,0 +1,11 @@
+export default function SSRPage(props) {
+  return <h1>{props.message}</h1>
+}
+
+export const getServerSideProps = (req) => {
+  return {
+    props: {
+      message: 'Bye Cruel World',
+    },
+  }
+}

test/integration/middleware-general/pages/ssr-page.js

@@ -0,0 +1,11 @@
+export default function SSRPage(props) {
+  return <h1>{props.message}</h1>
+}
+
+export const getServerSideProps = (req) => {
+  return {
+    props: {
+      message: 'Hello World',
+    },
+  }
+}

test/integration/middleware-general/test/index.test.js

@@ -29,6 +29,7 @@ describe('Middleware Runtime', () => {
     beforeAll(async () => {
       context.dev = true
       context.appPort = await findPort()
+      context.buildId = 'development'
       context.app = await launchApp(context.appDir, context.appPort, {
         env: {
           MIDDLEWARE_TEST: 'asdf',
@@ -83,6 +84,11 @@ describe('Middleware Runtime', () => {
         stdout: true,
       })
 
+      context.buildId = await fs.readFile(
+        join(context.appDir, '.next/BUILD_ID'),
+        'utf8'
+      )
+
       context.buildLogs = {
         output: build.stdout + build.stderr,
         stderr: build.stderr,
@@ -279,6 +285,18 @@ function tests(context, locale = '') {
     )
     expect(readMiddlewareError(response)).toContain(urlsError)
   })
+
+  it('should trigger middleware for data requests', async () => {
+    const browser = await webdriver(context.appPort, `/ssr-page`)
+    const text = await browser.elementByCss('h1').text()
+    expect(text).toEqual('Bye Cruel World')
+    const res = await fetchViaHTTP(
+      context.appPort,
+      `/_next/data/${context.buildId}/en/ssr-page.json`
+    )
+    const json = await res.json()
+    expect(json.pageProps.message).toEqual('Bye Cruel World')
+  })
 }
 
 function readMiddlewareJSON(response) {