Test static folder (#9395)

* Test for infinite loop

* remove focus

test/integration/serverless/test/index.test.js

@@ -13,6 +13,7 @@ import {
   renderViaHTTP,
 } from 'next-test-utils'
 import qs from 'querystring'
+import path from 'path'
 import fetch from 'node-fetch'
 
 const appDir = join(__dirname, '../')
@@ -62,6 +63,17 @@ describe('Serverless', () => {
     expect(legacy).toMatch(`new static folder`)
   })
 
+  it('should not infinity loop on a 404 static file', async () => {
+    expect.assertions(2)
+
+    // ensure top-level static does not exist (important for test)
+    // we expect /public/static, though.
+    expect(existsSync(path.join(appDir, 'static'))).toBe(false)
+
+    const res = await fetchViaHTTP(appPort, '/static/404')
+    expect(res.status).toBe(404)
+  })
+
   it('should render the page with dynamic import', async () => {
     const html = await renderViaHTTP(appPort, '/dynamic')
     expect(html).toMatch(/Hello!/)