Testing: use a better way to get a port to the test app (#753)

* Randomize the port returned from test util's findPort().

* Use http's server.listen() to bind to a random available port.

* Update yarn.lock

* Update yarn.lock

package.json

@@ -104,9 +104,6 @@
     "jest-cli": "^18.0.0",
     "node-fetch": "^1.6.3",
     "nyc": "^10.0.0",
-    "portfinder": "^1.0.10",
-    "react": "15.4.2",
-    "react-dom": "15.4.2",
     "run-sequence": "1.2.2",
     "standard": "8.6.0",
     "wd": "^1.1.3",

test/integration/basic/test/index.test.js

@@ -3,9 +3,10 @@
 import { join } from 'path'
 import {
   nextServer,
-  findPort,
   renderViaAPI,
-  renderViaHTTP
+  renderViaHTTP,
+  startApp,
+  stopApp
 } from 'next-test-utils'
 
 // test suits
@@ -25,11 +26,10 @@ jasmine.DEFAULT_TIMEOUT_INTERVAL = 40000
 
 describe('Basic Features', () => {
   beforeAll(async () => {
-    await context.app.prepare()
-    context.appPort = await findPort()
-    await context.app.start(context.appPort)
+    context.server = await startApp(context.app)
+    context.appPort = context.server.address().port
   })
-  afterAll(() => context.app.close())
+  afterAll(() => stopApp(context.server))
 
   rendering(context, 'Rendering via API', (p, q) => renderViaAPI(context.app, p, q))
   rendering(context, 'Rendering via HTTP', (p, q) => renderViaHTTP(context.appPort, p, q))

test/integration/production/test/index.test.js

@@ -5,13 +5,15 @@ import { join } from 'path'
 import {
   nextServer,
   nextBuild,
-  findPort,
+  startApp,
+  stopApp,
   renderViaHTTP
 } from 'next-test-utils'
 
 const appDir = join(__dirname, '../')
-let app
 let appPort
+let server
+let app
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 40000
 
 describe('Production Usage', () => {
@@ -23,11 +25,10 @@ describe('Production Usage', () => {
       quiet: true
     })
 
-    await app.prepare()
-    appPort = await findPort()
-    await app.start(appPort)
+    server = await startApp(app)
+    appPort = server.address().port
   })
-  afterAll(() => app.close())
+  afterAll(() => stopApp(server))
 
   describe('With basic usage', () => {
     it('should render the page', async () => {

test/lib/next-test-utils.js

-import portFinder from 'portfinder'
 import fetch from 'node-fetch'
 import qs from 'querystring'
+import http from 'http'
 
 import server from '../../dist/server/next'
 import build from '../../dist/server/build'
@@ -10,15 +10,6 @@ export const nextServer = server
 export const nextBuild = build
 export const pkg = _pkg
 
-export function findPort () {
-  return new Promise((resolve, reject) => {
-    portFinder.getPort((err, port) => {
-      if (err) return reject(err)
-      return resolve(port)
-    })
-  })
-}
-
 export function renderViaAPI (app, pathname, query = {}) {
   return app.renderToHTML({}, {}, pathname, query)
 }
@@ -27,3 +18,32 @@ export function renderViaHTTP (appPort, pathname, query = {}) {
   const url = `http://localhost:${appPort}${pathname}?${qs.stringify(query)}`
   return fetch(url).then((res) => res.text())
 }
+
+export async function startApp (app) {
+  await app.prepare()
+  const handler = app.getRequestHandler()
+  const server = http.createServer(handler)
+  server.__app = app
+
+  await promiseCall(server, 'listen')
+  return server
+}
+
+export async function stopApp (app) {
+  await server.__app.close()
+  await promiseCall(server, 'close')
+}
+
+function promiseCall (obj, method, ...args) {
+  return new Promise((resolve, reject) => {
+    const newArgs = [
+      ...args,
+      function (err, res) {
+        if (err) return reject(err)
+        resolve(res)
+      }
+    ]
+
+    obj[method](...newArgs)
+  })
+}