Use a random TCP port for testing timeouts/rejects

This fixes a test failure when the host has something listening
on the LDAP TCP port. Previously, the test cases would assume
that the port was free and they would not connect.

For #612

Author: rkaw92

package.json

@@ -27,6 +27,7 @@
     "verror": "^1.8.1"
   },
   "devDependencies": {
+    "get-port": "^5.1.1",
     "husky": "^3.0.4",
     "snazzy": "^8.0.0",
     "standard": "^14.0.2",

test/client.test.js

@@ -5,6 +5,7 @@ const assert = require('assert')
 const tap = require('tap')
 const uuid = require('uuid')
 const vasync = require('vasync')
+const getPort = require('get-port')
 const { getSock } = require('./utils')
 const ldap = require('../lib')
 const { Attribute, Change } = ldap
@@ -1495,40 +1496,44 @@ tap.test('resultError handling', function (t) {
 })
 
 tap.test('connection refused', function (t) {
-  const client = ldap.createClient({
-    url: 'ldap://0.0.0.0'
-  })
+  getPort().then(function (unusedPortNumber) {
+    const client = ldap.createClient({
+      url: `ldap://0.0.0.0:${unusedPortNumber}`
+    })
 
-  client.bind('cn=root', 'secret', function (err, res) {
-    t.true(err)
-    t.type(err, Error)
-    t.equals(err.code, 'ECONNREFUSED')
-    t.false(res)
-    t.end()
+    client.bind('cn=root', 'secret', function (err, res) {
+      t.true(err)
+      t.type(err, Error)
+      t.equals(err.code, 'ECONNREFUSED')
+      t.false(res)
+      t.end()
+    })
   })
 })
 
 tap.test('connection timeout', function (t) {
-  const client = ldap.createClient({
-    url: 'ldap://example.org',
-    connectTimeout: 1,
-    timeout: 1
-  })
+  getPort().then(function (unusedPortNumber) {
+    const client = ldap.createClient({
+      url: `ldap://example.org:${unusedPortNumber}`,
+      connectTimeout: 1,
+      timeout: 1
+    })
 
-  var done = false
+    var done = false
 
-  setTimeout(function () {
-    if (!done) {
-      throw new Error('LDAPJS waited for the server for too long')
-    }
-  }, 2000)
-
-  client.bind('cn=root', 'secret', function (err, res) {
-    t.true(err)
-    t.type(err, Error)
-    t.equals(err.message, 'connection timeout')
-    done = true
-    t.false(res)
-    t.end()
+    setTimeout(function () {
+      if (!done) {
+        throw new Error('LDAPJS waited for the server for too long')
+      }
+    }, 2000)
+
+    client.bind('cn=root', 'secret', function (err, res) {
+      t.true(err)
+      t.type(err, Error)
+      t.equals(err.message, 'connection timeout')
+      done = true
+      t.false(res)
+      t.end()
+    })
   })
 })