feat(mitm): support "mitm" behavior

Supplying `{mitm: true}` to `connect()` in lieu of URL (or path) will
assume [mitm](https://npm.im/mitm) is in use.  A dummy port is handed
to `net.createConnection()`.

- swaps `pify` for `promwrap`
- improved test harnesses
- added pending tests where more coverage is needed

Author: boneskull

lib/index.js

@@ -1,7 +1,7 @@
 'use strict';
 
 const MQTT = require('mqtt');
-const pify = require('pify');
+const promisify = require('promwrap');
 const net = require('net');
 const {EventEmitter2} = require('eventemitter2');
 const decoders = require('./decoders');
@@ -26,7 +26,7 @@ const asyncMethodNames = ['publish', 'subscribe', 'unsubscribe', 'end'];
  */
 const toadpatch = (client, baseOpts = {}) => {
   const asyncMethods = asyncMethodNames.reduce(
-    (acc, name) => Object.assign(acc, {[name]: pify(client[name])}),
+    (acc, name) => Object.assign(acc, {[name]: promisify(client[name])}),
     {}
   );
 
@@ -147,7 +147,7 @@ const toadpatch = (client, baseOpts = {}) => {
 
 const normalizeOptions = (opts = {}, defaults = DEFAULT_OPTS) => {
   [['decoder', decoders], ['encoder', encoders]].forEach(([prop, builtins]) => {
-    if (opts.hasOwnProperty(prop)) {
+    if (prop in opts) {
       if (typeof opts[prop] === 'string') {
         const value = builtins[opts[prop]];
         if (!value) {
@@ -181,9 +181,10 @@ exports.connect = async (url, opts = {}) => {
     opts = normalizeOptions(url);
     args = [opts];
   }
+  const path = opts.mitm ? 1833 : opts.path;
   return new Promise((resolve, reject) => {
-    (opts.path
-      ? MQTT.MqttClient(() => net.createConnection(opts.path), {
+    (path
+      ? MQTT.MqttClient(() => net.createConnection(path), {
           resubscribe: false
         })
       : MQTT.connect(...args)

package-lock.json

@@ -31,7 +31,7 @@
   "dependencies": {
     "eventemitter2": "^4.1.2",
     "mqtt": "^2.15.1",
-    "pify": "^3.0.0"
+    "promwrap": "^2.1.0"
   },
   "files": [
     "lib"
@@ -50,11 +50,13 @@
     "get-port": "^3.2.0",
     "husky": "^0.14.3",
     "lint-staged": "^4.2.3",
+    "mitm": "^1.3.3",
     "mocha": "^4.0.1",
     "mqtt-connection": "^3.1.0",
     "nyc": "^11.2.1",
     "prettier-eslint-cli": "^4.4.0",
     "semantic-release": "^8.0.3",
+    "stoppable": "^1.0.5",
     "unexpected": "^10.36.0"
   },
   "engines": {

package.json

@@ -3,22 +3,48 @@
 const _ = require('lodash');
 const {Server} = require('net');
 const MqttConnection = require('mqtt-connection');
+const MITM = require('mitm');
+const promisify = require('promwrap');
+const stoppable = require('stoppable');
 
-class Broker extends Server {
+class BaseServer extends Server {
   constructor(listener) {
     super();
-    this.on('connection', stream => {
-      this.emit('client', new MqttConnection(stream));
-    });
+
     if (listener) {
       this.on('client', listener);
     }
   }
 }
 
-exports.Broker = Broker;
+class Broker extends BaseServer {
+  constructor(listener) {
+    super(listener);
+
+    this.on('connection', sock => {
+      this.emit('client', new MqttConnection(sock));
+    });
+  }
+}
+
+class MITMBroker extends BaseServer {
+  listen(ignored, done) {
+    this.mitm = MITM();
+    this.mitm.on('connection', sock => {
+      this.emit('client', new MqttConnection(sock));
+    });
+    process.nextTick(done);
+  }
 
-exports.createBroker = async (port, transformers = {}) => {
+  close(done) {
+    this.mitm.disable();
+    process.nextTick(done);
+  }
+}
+
+exports.Broker = BaseServer;
+
+exports.createBroker = async ({port, path, mitm, transformers = {}} = {}) => {
   transformers = _.defaults(transformers, {
     connack(...args) {
       return {returnCode: 0};
@@ -35,7 +61,8 @@ exports.createBroker = async (port, transformers = {}) => {
     pubrec: _.identity,
     publish: _.identity
   });
-  const broker = new Broker(client => {
+
+  const listener = client => {
     client
       .on('connect', (...args) => {
         client.connack(transformers.connack(...args));
@@ -70,28 +97,17 @@ exports.createBroker = async (port, transformers = {}) => {
               break;
           }
         });
-      })
-      .on('close', () => {
-        client.destroy();
-      })
-      .on('error', () => {
-        client.destroy();
-      })
-      .on('timeout', () => {
-        client.destroy();
-      })
-      .on('disconnect', () => {
-        client.destroy();
       });
-  });
+  };
+
+  const broker = stoppable(new (mitm ? MITMBroker : Broker)(listener), 0);
   broker.transformers = transformers;
   broker.port = port;
-  return new Promise((resolve, reject) => {
-    broker.listen(port, err => {
-      if (err) {
-        return reject(err);
-      }
-      resolve(broker);
-    });
+  broker.path = path;
+  const promisifiedBroker = promisify(broker, {
+    exclude: ['unref', 'address', 'ref']
   });
+
+  await promisifiedBroker.listen(port || path);
+  return promisifiedBroker;
 };