test(e2e): Add test for Next.js middleware

packages/e2e-tests/test-applications/nextjs-app-dir/middleware.ts

@@ -0,0 +1,15 @@
+import { NextResponse } from 'next/server';
+import type { NextRequest } from 'next/server';
+
+export function middleware(request: NextRequest) {
+  if (request.headers.has('x-should-throw')) {
+    throw new Error('Middleware Error');
+  }
+
+  return NextResponse.next();
+}
+
+// See "Matching Paths" below to learn more
+export const config = {
+  matcher: ['/api/endpoint-behind-middleware'],
+};

packages/e2e-tests/test-applications/nextjs-app-dir/pages/api/endpoint-behind-middleware.ts

@@ -0,0 +1,9 @@
+import type { NextApiRequest, NextApiResponse } from 'next';
+
+type Data = {
+  name: string;
+};
+
+export default function handler(req: NextApiRequest, res: NextApiResponse<Data>) {
+  res.status(200).json({ name: 'John Doe' });
+}

packages/e2e-tests/test-applications/nextjs-app-dir/tests/middleware.test.ts

@@ -0,0 +1,53 @@
+import { test, expect } from '@playwright/test';
+import { waitForTransaction, waitForError } from '../../../test-utils/event-proxy-server';
+
+test('Should create a transaction for middleware', async ({ request }) => {
+  test.skip(process.env.TEST_ENV === 'development', "Doesn't work in dev mode.");
+
+  const middlewareTransactionPromise = waitForTransaction('nextjs-13-app-dir', async transactionEvent => {
+    return transactionEvent?.transaction === 'middleware' && transactionEvent?.contexts?.trace?.status === 'ok';
+  });
+
+  const response = await request.get('/api/endpoint-behind-middleware');
+  expect(await response.json()).toStrictEqual({ name: 'John Doe' });
+
+  const middlewareTransaction = await middlewareTransactionPromise;
+
+  expect(middlewareTransaction.contexts?.trace?.status).toBe('ok');
+  expect(middlewareTransaction.contexts?.trace?.op).toBe('middleware.nextjs');
+  expect(middlewareTransaction.contexts?.runtime?.name).toBe('edge');
+});
+
+test('Should create a transaction with error status for faulty middleware', async ({ request }) => {
+  test.skip(process.env.TEST_ENV === 'development', "Doesn't work in dev mode.");
+
+  const middlewareTransactionPromise = waitForTransaction('nextjs-13-app-dir', async transactionEvent => {
+    return (
+      transactionEvent?.transaction === 'middleware' && transactionEvent?.contexts?.trace?.status === 'internal_error'
+    );
+  });
+
+  request.get('/api/endpoint-behind-middleware', { headers: { 'x-should-throw': '1' } }).catch(() => {
+    // Noop
+  });
+
+  const middlewareTransaction = await middlewareTransactionPromise;
+
+  expect(middlewareTransaction.contexts?.trace?.status).toBe('internal_error');
+  expect(middlewareTransaction.contexts?.trace?.op).toBe('middleware.nextjs');
+  expect(middlewareTransaction.contexts?.runtime?.name).toBe('edge');
+});
+
+test('Records exceptions happening in middleware', async ({ request }) => {
+  test.skip(process.env.TEST_ENV === 'development', "Doesn't work in dev mode.");
+
+  const errorEventPromise = waitForError('nextjs-13-app-dir', errorEvent => {
+    return errorEvent?.exception?.values?.[0]?.value === 'Middleware Error';
+  });
+
+  request.get('/api/endpoint-behind-middleware', { headers: { 'x-should-throw': '1' } }).catch(() => {
+    // Noop
+  });
+
+  expect(await errorEventPromise).toBeDefined();
+});