add e2e test

examples/pages-router/next.config.js

@@ -12,6 +12,17 @@ const nextConfig = {
   eslint: {
     ignoreDuringBuilds: true,
   },
+  headers: () => [
+    {
+      source: "/",
+      headers: [
+        {
+          key: "x-custom-header",
+          value: "my custom header value",
+        },
+      ],
+    },
+  ],
   rewrites: () => [
     { source: "/rewrite", destination: "/", locale: false },
     {

examples/pages-router/src/middleware.ts

@@ -0,0 +1,13 @@
+import { NextRequest, NextResponse } from "next/server";
+
+export function middleware(request: NextRequest) {
+  return NextResponse.next({
+    headers: {
+      "x-from-middleware": "true",
+    },
+  });
+}
+
+export const config = {
+  matcher: ["/"],
+};

packages/tests-e2e/tests/pagesRouter/i18n.test.ts

@@ -0,0 +1,17 @@
+import { expect, test } from "@playwright/test";
+
+test("Next config headers with i18n", async ({ page }) => {
+  const responsePromise = page.waitForResponse((response) => {
+    return response.status() === 200;
+  });
+  await page.goto("/");
+
+  const response = await responsePromise;
+  // Response header should be set
+  const headers = response.headers();
+  // Headers from next.config.js should be set
+  expect(headers["x-custom-header"]).toEqual("my custom header value");
+
+  // Headers from middleware should be set
+  expect(headers["x-from-middleware"]).toEqual("true");
+});