automatic port "discovery" for packets and server tests (#870)

* automatic port "discovery" for packets and server tests

* Semi-colon begone!

* move getport to commons file - u9g

* Merge code

test/clientTest.js

@@ -2,7 +2,6 @@
 
 const mc = require('../')
 const os = require('os')
-const net = require('net')
 const path = require('path')
 const assert = require('power-assert')
 const SURVIVE_TIME = 10000
@@ -13,14 +12,7 @@ const Wrap = require('minecraft-wrap').Wrap
 
 const download = util.promisify(require('minecraft-wrap').download)
 
-const getPort = () => new Promise(resolve => {
-  const server = net.createServer()
-  server.listen(0, '127.0.0.1')
-  server.on('listening', () => {
-    const { port } = server.address()
-    server.close(() => resolve(port))
-  })
-})
+const { getPort } = require('./common/util')
 
 for (const supportedVersion of mc.supportedVersions) {
   let PORT = null

test/common/util.js

@@ -0,0 +1,12 @@
+const net = require('net')
+
+const getPort = () => new Promise(resolve => {
+  const server = net.createServer()
+  server.listen(0, '127.0.0.1')
+  server.on('listening', () => {
+    const { port } = server.address()
+    server.close(() => resolve(port))
+  })
+})
+
+module.exports = { getPort }

test/packetTest.js

@@ -8,6 +8,8 @@ const assert = require('power-assert')
 const getFieldInfo = require('protodef').utils.getFieldInfo
 const getField = require('protodef').utils.getField
 
+const { getPort } = require('./common/util')
+
 function evalCount (count, fields) {
   if (fields[count.field] in count.map) { return count.map[fields[count.field]] }
   return count.default
@@ -188,24 +190,29 @@ function getValue (_type, packet) {
 }
 
 for (const supportedVersion of mc.supportedVersions) {
-  const PORT = Math.round(30000 + Math.random() * 20000)
+  let PORT
+
   const mcData = require('minecraft-data')(supportedVersion)
   const version = mcData.version
   const packets = mcData.protocol
 
   describe('packets ' + version.minecraftVersion, function () {
     let client, server, serverClient
-    before(function (done) {
+    before(async function () {
+      PORT = await getPort()
       server = new Server(version.minecraftVersion)
-      server.once('listening', function () {
-        server.once('connection', function (c) {
-          serverClient = c
-          done()
+      return new Promise((resolve) => {
+        console.log(`Using port for tests: ${PORT}`)
+        server.once('listening', function () {
+          server.once('connection', function (c) {
+            serverClient = c
+            resolve()
+          })
+          client = new Client(false, version.minecraftVersion)
+          client.setSocket(net.connect(PORT, 'localhost'))
         })
-        client = new Client(false, version.minecraftVersion)
-        client.setSocket(net.connect(PORT, 'localhost'))
+        server.listen(PORT, 'localhost')
       })
-      server.listen(PORT, 'localhost')
     })
     after(function (done) {
       client.on('end', function () {

test/serverTest.js

@@ -4,6 +4,8 @@ const mc = require('../')
 const assert = require('power-assert')
 const { once } = require('events')
 
+const { getPort } = require('./common/util')
+
 const w = {
   piglin_safe: {
     type: 'byte',
@@ -60,11 +62,17 @@ const w = {
 }
 
 for (const supportedVersion of mc.supportedVersions) {
-  const PORT = Math.round(30000 + Math.random() * 20000)
+  let PORT
   const mcData = require('minecraft-data')(supportedVersion)
   const version = mcData.version
 
   describe('mc-server ' + version.minecraftVersion, function () {
+
+    this.beforeAll(async function() {
+      PORT = await getPort()
+      console.log(`Using port for tests: ${PORT}`)
+    })
+
     this.timeout(5000)
     it('starts listening and shuts down cleanly', function (done) {
       const server = mc.createServer({