diff --git a/Dockerfile b/Dockerfile
index cb49be9..4763f28 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,3 +1,3 @@
-FROM node
+FROM node:4
 
 RUN npm install -g yarn
diff --git a/README.md b/README.md
index 8a93d49..e94b562 100644
--- a/README.md
+++ b/README.md
@@ -12,46 +12,50 @@ Helper for testing Hubot script.
 
 If you have a following hubot script:
 
-```coffee
-module.exports = (robot) ->
-  robot.respond /hi$/i, (msg) ->
-    msg.reply 'hi'
+```javascript
+module.exports = robot =>
+  robot.respond(/hi$/i, msg => msg.reply('hi'))
 ```
 
 You can test it like:
 
-```coffee
-Helper = require('hubot-test-helper')
-# helper loads all scripts passed a directory
-helper = new Helper('./scripts')
-
-# helper loads a specific script if it's a file
-scriptHelper = new Helper('./scripts/specific-script.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'hello-world', ->
-
-  beforeEach ->
-    @room = helper.createRoom()
-
-  afterEach ->
-    @room.destroy()
-
-  context 'user says hi to hubot', ->
-    beforeEach ->
-      co =>
-        yield @room.user.say 'alice', '@hubot hi'
-        yield @room.user.say 'bob',   '@hubot hi'
-
-    it 'should reply to user', ->
-      expect(@room.messages).to.eql [
-        ['alice', '@hubot hi']
-        ['hubot', '@alice hi']
-        ['bob',   '@hubot hi']
+```javascript
+const Helper = require('hubot-test-helper');
+// helper loads all scripts passed a directory
+const helper = new Helper('./scripts');
+
+// helper loads a specific script if it's a file
+const scriptHelper = new Helper('./scripts/specific-script.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('hello-world', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom();
+  });
+  afterEach(function() {
+    this.room.destroy();
+  });
+
+  context('user says hi to hubot', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('alice', '@hubot hi');
+        yield this.room.user.say('bob',   '@hubot hi');
+      }.bind(this));
+    });
+
+    it('should reply to user', function() {
+      expect(this.room.messages).to.eql([
+        ['alice', '@hubot hi'],
+        ['hubot', '@alice hi'],
+        ['bob',   '@hubot hi'],
         ['hubot', '@bob hi']
-      ]
+      ]);
+    });
+  });
+});
 ```
 
 #### HTTPD
@@ -62,7 +66,7 @@ tests and so requires it to be shutdown during teardown using `room.destroy()`.
 This feature can be turned off in tests that don't need it by passing using
 `helper.createRoom(httpd: false)`.
 
-See [the tests](test/httpd-world_test.coffee) for an example of testing the
+See [the tests](test/httpd-world_test.js) for an example of testing the
 HTTP server.
 
 
@@ -74,47 +78,53 @@ in testing we may anticipate the delayed reply with a manual time delay.
 
 For example we have the following script:
 
-```coffee
-module.exports = (robot) ->
-  robot.hear /(http(?:s?):\/\/(\S*))/i, (res) ->
-    url = res.match[1]
-    res.send "ok1: #{url}"
-    robot.http(url).get() (err, response, body) ->
-      res.send "ok2: #{url}"
+```javascript
+module.exports = robot =>
+  robot.hear(/(http(?:s?):\/\/(\S*))/i, res => {
+    const url = res.match[1];
+    res.send(`ok1: ${url}`);
+    robot.http(url).get()((err, response, body) => res.send(`ok2: ${url}`));
+  });
 ```
 
 To test the second callback response "ok2: ..." we use the following script:
 
-```coffee
-Helper = require('hubot-test-helper')
-helper = new Helper('../scripts/http.coffee')
-
-Promise= require('bluebird')
-co     = require('co')
-expect = require('chai').expect
-
-# test ping
-describe 'http', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  # Test case
-  context 'user posts link', ->
-    beforeEach ->
-      co =>
-        yield @room.user.say 'user1', 'http://google.com'
-        # delay one second for the second
-        # callback message to be posted to @room
-        yield new Promise.delay(1000)
-
-    # response
-    it 'expects deplayed callback from ok2', ->
-      console.log @room.messages
-      expect(@room.messages).to.eql [
-        ['user1', 'http://google.com']
-        ['hubot', 'ok1: http://google.com']
+```javascript
+const Helper = require('hubot-test-helper');
+const helper = new Helper('../scripts/http.js');
+
+const Promise = require('bluebird');
+const co      = require('co');
+const expect  = require('chai').expect;
+
+// test ping
+describe('http', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  // Test case
+  context('user posts link', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('user1', 'http://google.com');
+        // delay one second for the second
+        // callback message to be posted to @room
+        yield new Promise.delay(1000);
+      }.bind(this));
+    });
+
+    // response
+    it('expects deplayed callback from ok2', function() {
+      console.log(this.room.messages);
+      expect(this.room.messages).to.eql([
+        ['user1', 'http://google.com'],
+        ['hubot', 'ok1: http://google.com'],
         ['hubot', 'ok2: http://google.com']
-      ]
+      ]);
+    });
+  });
+});
 ```
 
 Note that `yield` and *generators* are part of [**ECMA6**](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function*), so it may not work on older node.js versions. It will wait for the delay to complete the `beforeEach` before proceeding to the test `it`.
@@ -128,37 +138,41 @@ may want to test the creation of a
 
 Given the following script:
 
-```coffee
-module.exports = (robot) ->
-
-  robot.respond /check status$/i, (msg) ->
-    robot.emit 'slack.attachment',
+```javascript
+module.exports = robot =>
+  robot.respond(/check status$/i, msg =>
+    robot.emit('slack.attachment', {
       message: msg.message,
       content: {
-        color: "good"
+        color: "good",
         text: "It's all good!"
       }
+    })
+  )
 ```
 
 you could test the emitted event like this:
 
-```coffee
-Helper = require 'hubot-test-helper'
-helper = new Helper('../scripts/status_check.coffee')
+```javascript
+const Helper = require('hubot-test-helper');
+const helper = new Helper('../scripts/status_check.js');
 
-expect = require('chai').expect
+const expect = require('chai').expect;
 
-describe 'status check', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
+describe('status check', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
 
-  it 'should send a slack event', ->
-    response = null
-    @room.robot.on 'slack.attachment', (event) ->
-      response = event.content
+  it('should send a slack event', function() {
+    let response = null;
+    this.room.robot.on('slack.attachment', event => response = event.content);
 
-    @room.user.say('bob', '@hubot check status').then =>
-      expect(response.text).to.eql("It's all good!")
+    this.room.user.say('bob', '@hubot check status').then(() => {
+      expect(response.text).to.eql("It's all good!");
+    });
+  });
+});
 ```
 
 ## Development
diff --git a/package.json b/package.json
index dbe72d9..1f7902b 100644
--- a/package.json
+++ b/package.json
@@ -1,23 +1,22 @@
 {
   "name": "hubot-test-helper",
   "description": "Helper for testing hubot script",
-  "main": "./lib/index.js",
+  "main": "./src/index.js",
   "scripts": {
     "test": "mocha --compilers coffee:coffee-script/register test",
-    "semantic-release": "semantic-release pre && npm publish && semantic-release post",
-    "prepublish": "coffee --compile --output lib/ src/"
+    "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "keywords": [
     "hubot"
   ],
   "dependencies": {
-    "hubot": ">=2.6.0 <10 || 0.0.0-development"
+    "hubot": ">=3.0.0 <10 || 0.0.0-development"
   },
   "devDependencies": {
     "chai": "latest",
     "co": "latest",
-    "coffee-script": "latest",
     "mocha": "latest",
+    "coffee-script": "latest",
     "semantic-release": "latest"
   },
   "author": "Fumiaki MATSUSHIMA",
diff --git a/src/index.coffee b/src/index.coffee
deleted file mode 100644
index 404071f..0000000
--- a/src/index.coffee
+++ /dev/null
@@ -1,105 +0,0 @@
-Fs    = require('fs')
-Path  = require('path')
-Hubot = require('hubot')
-
-process.setMaxListeners(0)
-
-class MockResponse extends Hubot.Response
-  sendPrivate: (strings...) ->
-    @robot.adapter.sendPrivate @envelope, strings...
-
-class MockRobot extends Hubot.Robot
-  constructor: (httpd=true) ->
-    super null, null, httpd, 'hubot'
-
-    @Response = MockResponse
-
-  loadAdapter: ->
-    @adapter = new Room(@)
-
-class Room extends Hubot.Adapter
-  constructor: (@robot) ->
-    @messages = []
-
-    @privateMessages = {}
-
-    @user =
-      say: (userName, message, userParams) =>
-        @receive(userName, message, userParams)
-
-      enter: (userName, userParams) =>
-        @enter(userName, userParams)
-
-      leave: (userName, userParams) =>
-        @leave(userName, userParams)
-
-  receive: (userName, message, userParams = {}) ->
-    new Promise (resolve) =>
-      textMessage = null
-      if typeof message is 'object' and message
-        textMessage = message
-      else
-        userParams.room = @name
-        user = new Hubot.User(userName, userParams)
-        textMessage = new Hubot.TextMessage(user, message)
-
-      @messages.push [userName, textMessage.text]
-      @robot.receive(textMessage, resolve)
-
-  destroy: ->
-    @robot.server.close() if @robot.server
-
-  reply: (envelope, strings...) ->
-    @messages.push ['hubot', "@#{envelope.user.name} #{str}"] for str in strings
-
-  send: (envelope, strings...) ->
-    @messages.push ['hubot', str] for str in strings
-
-  sendPrivate: (envelope, strings...) ->
-    if envelope.user.name not of @privateMessages
-      @privateMessages[envelope.user.name] = []
-    @privateMessages[envelope.user.name].push ['hubot', str] for str in strings
-
-  robotEvent: () ->
-    @robot.emit.apply(@robot, arguments)
-
-  enter: (userName, userParams = {}) ->
-    new Promise (resolve) =>
-      userParams.room = @name
-      user = new Hubot.User(userName, userParams)
-      @robot.receive(new Hubot.EnterMessage(user), resolve)
-
-  leave: (userName, userParams = {}) ->
-    new Promise (resolve) =>
-      userParams.room = @name
-      user = new Hubot.User(userName, userParams)
-      @robot.receive(new Hubot.LeaveMessage(user), resolve)
-
-class Helper
-  @Response = MockResponse
-
-  constructor: (scriptsPaths) ->
-    if not Array.isArray(scriptsPaths)
-      scriptsPaths = [scriptsPaths]
-    @scriptsPaths = scriptsPaths
-
-  createRoom: (options={}) ->
-    robot = new MockRobot(options.httpd)
-
-    if 'response' of options
-      robot.Response = options.response
-
-    for script in @scriptsPaths
-      script = Path.resolve(Path.dirname(module.parent.filename), script)
-      if Fs.statSync(script).isDirectory()
-        for file in Fs.readdirSync(script).sort()
-          robot.loadFile script, file
-      else
-        robot.loadFile Path.dirname(script), Path.basename(script)
-
-    robot.brain.emit 'loaded'
-
-    robot.adapter.name = options.name or 'room1'
-    robot.adapter
-
-module.exports = Helper
diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..dd29a51
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,154 @@
+'use strict'
+
+const Fs    = require('fs');
+const Path  = require('path');
+const Hubot = require('hubot/es2015');
+
+process.setMaxListeners(0);
+
+class MockResponse extends Hubot.Response {
+  sendPrivate(/* ...strings*/) {
+    const strings = [].slice.call(arguments, 0);
+
+    this.robot.adapter.sendPrivate.apply(this.robot.adapter, [this.envelope].concat(strings));
+  }
+}
+
+class MockRobot extends Hubot.Robot {
+  constructor(httpd) {
+    if (httpd == null) { httpd = true; }
+    super(null, null, httpd, 'hubot');
+
+    this.Response = MockResponse;
+  }
+
+  loadAdapter() {
+    this.adapter = new Room(this);
+  }
+}
+
+class Room extends Hubot.Adapter {
+  // XXX: https://github.com/hubotio/hubot/pull/1390
+  static messages(obj) {
+    if (obj instanceof MockRobot) {
+      return obj.adapter.messages;
+    } else {
+      return obj.messages;
+    }
+  }
+
+  constructor(robot) {
+    super();
+    this.robot = robot;
+    this.messages = [];
+
+    this.privateMessages = {};
+
+    this.user = {
+      say: (userName, message, userParams) => this.receive(userName, message, userParams),
+      enter: (userName, userParams) => this.enter(userName, userParams),
+      leave: (userName, userParams) => this.leave(userName, userParams)
+    };
+  }
+
+  receive(userName, message, userParams) {
+    if (userParams == null) { userParams = {}; }
+    return new Promise(resolve => {
+      let textMessage = null;
+      if ((typeof message === 'object') && message) {
+        textMessage = message;
+      } else {
+        userParams.room = this.name;
+        const user = new Hubot.User(userName, userParams);
+        textMessage = new Hubot.TextMessage(user, message);
+      }
+
+      this.messages.push([userName, textMessage.text]);
+      this.robot.receive(textMessage, resolve);
+    });
+  }
+
+  destroy() {
+    if (this.robot.server) { this.robot.server.close(); }
+  }
+
+  reply(envelope/*, ...strings*/) {
+    const strings = [].slice.call(arguments, 1);
+
+    strings.forEach((str) => Room.messages(this).push(['hubot', `@${envelope.user.name} ${str}`]));
+  }
+
+  send(envelope/*, ...strings*/) {
+    const strings = [].slice.call(arguments, 1);
+
+    strings.forEach((str) => Room.messages(this).push(['hubot', str]));
+  }
+
+  sendPrivate(envelope/*, ...strings*/) {
+    const strings = [].slice.call(arguments, 1);
+
+    if (!(envelope.user.name in this.privateMessages)) {
+      this.privateMessages[envelope.user.name] = [];
+    }
+    strings.forEach((str) => this.privateMessages[envelope.user.name].push(['hubot', str]));
+  }
+
+  robotEvent() {
+    this.robot.emit.apply(this.robot, arguments);
+  }
+
+  enter(userName, userParams) {
+    if (userParams == null) { userParams = {}; }
+    return new Promise(resolve => {
+      userParams.room = this.name;
+      const user = new Hubot.User(userName, userParams);
+      this.robot.receive(new Hubot.EnterMessage(user), resolve);
+    });
+  }
+
+  leave(userName, userParams) {
+    if (userParams == null) { userParams = {}; }
+    return new Promise(resolve => {
+      userParams.room = this.name;
+      const user = new Hubot.User(userName, userParams);
+      this.robot.receive(new Hubot.LeaveMessage(user), resolve);
+    });
+  }
+}
+
+class Helper {
+  constructor(scriptsPaths) {
+    if (!Array.isArray(scriptsPaths)) {
+      scriptsPaths = [scriptsPaths];
+    }
+    this.scriptsPaths = scriptsPaths;
+  }
+
+  createRoom(options) {
+    if (options == null) { options = {}; }
+    const robot = new MockRobot(options.httpd);
+
+    if ('response' in options) {
+      robot.Response = options.response;
+    }
+
+    for (let script of this.scriptsPaths) {
+      script = Path.resolve(Path.dirname(module.parent.filename), script);
+      if (Fs.statSync(script).isDirectory()) {
+        for (let file of Fs.readdirSync(script).sort()) {
+          robot.loadFile(script, file);
+        }
+      } else {
+        robot.loadFile(Path.dirname(script), Path.basename(script));
+      }
+    }
+
+    robot.brain.emit('loaded');
+
+    robot.adapter.name = options.name || 'room1';
+    return robot.adapter;
+  }
+}
+Helper.Response = MockResponse;
+
+module.exports = Helper;
diff --git a/test/custom-text-message_test.coffee b/test/custom-text-message_test.coffee
deleted file mode 100644
index 89f5ec0..0000000
--- a/test/custom-text-message_test.coffee
+++ /dev/null
@@ -1,21 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/custom-text-message.coffee')
-Hubot = require('hubot')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'custom-text-message', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'Passing a custom text message object', ->
-    beforeEach ->
-      co =>
-        textMessage = new Hubot.TextMessage({}, '')
-        textMessage.isCustom = true
-        textMessage.custom = 'custom'
-        yield @room.user.say 'user', textMessage
-
-    it 'sends back', ->
-      expect(@room.messages[1][1]).to.be.equal('custom')
diff --git a/test/custom-text-message_test.js b/test/custom-text-message_test.js
new file mode 100644
index 0000000..208dfd6
--- /dev/null
+++ b/test/custom-text-message_test.js
@@ -0,0 +1,27 @@
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/custom-text-message.js');
+const Hubot = require('hubot');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('custom-text-message', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('Passing a custom text message object', function() {
+    beforeEach(function() {
+      return co(function*() {
+        const textMessage = new Hubot.TextMessage({}, '');
+        textMessage.isCustom = true;
+        textMessage.custom = 'custom';
+        yield this.room.user.say('user', textMessage);
+      }.bind(this));
+    });
+
+    it('sends back', function() {
+      expect(this.room.messages[1][1]).to.be.equal('custom');
+    });
+  });
+});
diff --git a/test/enter-leave_test.coffee b/test/enter-leave_test.coffee
deleted file mode 100644
index b559aad..0000000
--- a/test/enter-leave_test.coffee
+++ /dev/null
@@ -1,21 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/enter-leave.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'enter-leave', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'user entering then leaving the room', ->
-    beforeEach ->
-      co =>
-        yield @room.user.enter 'user1'
-        yield @room.user.leave 'user1'
-
-    it 'greets the user', ->
-      expect(@room.messages).to.eql [
-        ['hubot', 'Hi user1!']
-        ['hubot', 'Bye user1!']
-      ]
diff --git a/test/enter-leave_test.js b/test/enter-leave_test.js
new file mode 100644
index 0000000..b5ccd4d
--- /dev/null
+++ b/test/enter-leave_test.js
@@ -0,0 +1,29 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/enter-leave.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('enter-leave', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('user entering then leaving the room', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.enter('user1');
+        yield this.room.user.leave('user1');
+      }.bind(this));
+    });
+
+    it('greets the user', function() {
+      expect(this.room.messages).to.eql([
+        ['hubot', 'Hi user1!'],
+        ['hubot', 'Bye user1!']
+      ]);
+    });
+  });
+});
diff --git a/test/events_test.coffee b/test/events_test.coffee
deleted file mode 100644
index 54e1de7..0000000
--- a/test/events_test.coffee
+++ /dev/null
@@ -1,29 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/events.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'events', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'should post on an event', ->
-    beforeEach ->
-      @room.robotEvent 'some-event', 'event', 'data'
-
-    it 'should reply to user', ->
-      expect(@room.messages).to.eql [
-        ['hubot', 'got event with event data']
-      ]
-
-  context 'should hear events emitted by responses', ->
-
-
-    it 'should trigger an event', ->
-      response = null
-      @room.robot.on 'response-event', (event) ->
-        response = event.content
-
-      @room.user.say('bob', '@hubot send event').then =>
-        expect(response).to.eql('hello')
diff --git a/test/events_test.js b/test/events_test.js
new file mode 100644
index 0000000..3ed588e
--- /dev/null
+++ b/test/events_test.js
@@ -0,0 +1,36 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/events.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('events', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('should post on an event', function() {
+    beforeEach(function() {
+      this.room.robotEvent('some-event', 'event', 'data');
+    });
+
+    it('should reply to user', function() {
+      expect(this.room.messages).to.eql([
+        ['hubot', 'got event with event data']
+      ]);
+    });
+  });
+
+  context('should hear events emitted by responses', () =>
+    it('should trigger an event', function() {
+      let response = null;
+      this.room.robot.on('response-event', event => response = event.content);
+
+      this.room.user.say('bob', '@hubot send event').then(() => {
+        expect(response).to.eql('hello');
+      });
+    })
+  );
+});
diff --git a/test/hello-world-listener_test.coffee b/test/hello-world-listener_test.coffee
deleted file mode 100644
index c9314d1..0000000
--- a/test/hello-world-listener_test.coffee
+++ /dev/null
@@ -1,22 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/hello-world-listener.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'hello-world', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'user says hi to hubot', ->
-    beforeEach ->
-      co =>
-        yield @room.user.say 'alice', '@hubot hi'
-        yield @room.user.say 'bob',   '@hubot hi'
-
-    it 'should reply to user', ->
-      expect(@room.messages).to.eql [
-        ['alice', '@hubot hi']
-        ['bob',   '@hubot hi']
-        ['hubot', '@bob hi']
-      ]
diff --git a/test/hello-world-listener_test.js b/test/hello-world-listener_test.js
new file mode 100644
index 0000000..6cf4ef7
--- /dev/null
+++ b/test/hello-world-listener_test.js
@@ -0,0 +1,30 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/hello-world-listener.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('hello-world', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('user says hi to hubot', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('alice', '@hubot hi');
+        yield this.room.user.say('bob',   '@hubot hi');
+      }.bind(this));
+    });
+
+    it('should reply to user', function() {
+      expect(this.room.messages).to.eql([
+        ['alice', '@hubot hi'],
+        ['bob',   '@hubot hi'],
+        ['hubot', '@bob hi']
+      ]);
+    });
+  });
+});
diff --git a/test/hello-world_test.js b/test/hello-world_test.js
new file mode 100644
index 0000000..4c57d89
--- /dev/null
+++ b/test/hello-world_test.js
@@ -0,0 +1,34 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/hello-world.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('hello-world', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+  afterEach(function() {
+    this.room.destroy();
+  });
+
+  context('user says hi to hubot', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('alice', '@hubot hi');
+        yield this.room.user.say('bob',   '@hubot hi');
+      }.bind(this));
+    });
+
+    it('should reply to user', function() {
+      expect(this.room.messages).to.eql([
+        ['alice', '@hubot hi'],
+        ['hubot', '@alice hi'],
+        ['bob',   '@hubot hi'],
+        ['hubot', '@bob hi']
+      ]);
+    });
+  });
+});
diff --git a/test/httpd-world_test.coffee b/test/httpd-world_test.coffee
deleted file mode 100644
index 892b17d..0000000
--- a/test/httpd-world_test.coffee
+++ /dev/null
@@ -1,22 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts')
-http = require('http')
-
-expect = require('chai').expect
-
-process.env.EXPRESS_PORT = 8080
-
-describe 'httpd-world', ->
-  beforeEach ->
-    @room = helper.createRoom()
-
-  afterEach ->
-    @room.destroy()
-
-  context 'GET /hello/world', ->
-    beforeEach (done) ->
-      http.get 'http://localhost:8080/hello/world', (@response) => done()
-      .on 'error', done
-
-    it 'responds with status 200', ->
-      expect(@response.statusCode).to.equal 200
diff --git a/test/httpd-world_test.js b/test/httpd-world_test.js
new file mode 100644
index 0000000..2dcc8e2
--- /dev/null
+++ b/test/httpd-world_test.js
@@ -0,0 +1,32 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts');
+const http = require('http');
+
+const expect = require('chai').expect;
+
+process.env.EXPRESS_PORT = 8080;
+
+describe('httpd-world', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom();
+  });
+
+  afterEach(function() {
+    this.room.destroy();
+  });
+
+  context('GET /hello/world', function() {
+    beforeEach(function(done) {
+      http.get('http://localhost:8080/hello/world', response => {
+        this.response = response;
+        done();
+      }).on('error', done);
+    });
+
+    it('responds with status 200', function() {
+      expect(this.response.statusCode).to.equal(200);
+    });
+  });
+});
diff --git a/test/load-multiple-scripts_test.coffee b/test/load-multiple-scripts_test.coffee
deleted file mode 100644
index 19b80ca..0000000
--- a/test/load-multiple-scripts_test.coffee
+++ /dev/null
@@ -1,23 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper(['./scripts/hello-world.coffee', './scripts/bye.coffee'])
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'hello-world', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'user says hi to hubot', ->
-    beforeEach ->
-      co =>
-        yield @room.user.say 'alice', '@hubot hi'
-        yield @room.user.say 'bob',   '@hubot bye'
-
-    it 'should reply to user', ->
-      expect(@room.messages).to.eql [
-        ['alice', '@hubot hi']
-        ['hubot', '@alice hi']
-        ['bob',   '@hubot bye']
-        ['hubot', '@bob bye']
-      ]
diff --git a/test/load-multiple-scripts_test.js b/test/load-multiple-scripts_test.js
new file mode 100644
index 0000000..427e85e
--- /dev/null
+++ b/test/load-multiple-scripts_test.js
@@ -0,0 +1,31 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper(['./scripts/hello-world.js', './scripts/bye.js']);
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('hello-world', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('user says hi to hubot', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('alice', '@hubot hi');
+        yield this.room.user.say('bob',   '@hubot bye');
+      }.bind(this));
+    });
+
+    it('should reply to user', function() {
+      expect(this.room.messages).to.eql([
+        ['alice', '@hubot hi'],
+        ['hubot', '@alice hi'],
+        ['bob',   '@hubot bye'],
+        ['hubot', '@bob bye']
+      ]);
+    });
+  });
+});
diff --git a/test/mock-response_test.coffee b/test/mock-response_test.coffee
deleted file mode 100644
index 50ef691..0000000
--- a/test/mock-response_test.coffee
+++ /dev/null
@@ -1,27 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/mock-response.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-class NewMockResponse extends Helper.Response
-  random: (items) ->
-    3
-
-describe 'mock-response', ->
-  beforeEach ->
-    @room = helper.createRoom(response: NewMockResponse, httpd: false)
-
-  context 'user says "give me a random" number to hubot', ->
-    beforeEach ->
-      co =>
-        yield @room.user.say 'alice', '@hubot give me a random number'
-        yield @room.user.say 'bob',   '@hubot give me a random number'
-
-    it 'should reply to user with a random number', ->
-      expect(@room.messages).to.eql [
-        ['alice', '@hubot give me a random number']
-        ['hubot', '@alice 3']
-        ['bob',   '@hubot give me a random number']
-        ['hubot', '@bob 3']
-      ]
diff --git a/test/mock-response_test.js b/test/mock-response_test.js
new file mode 100644
index 0000000..d116ab7
--- /dev/null
+++ b/test/mock-response_test.js
@@ -0,0 +1,37 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/mock-response.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+class NewMockResponse extends Helper.Response {
+  random(items) {
+    return 3;
+  }
+}
+
+describe('mock-response', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({response: NewMockResponse, httpd: false});
+  });
+
+  context('user says "give me a random" number to hubot', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('alice', '@hubot give me a random number');
+        yield this.room.user.say('bob',   '@hubot give me a random number');
+      }.bind(this));
+    });
+
+    it('should reply to user with a random number', function() {
+      expect(this.room.messages).to.eql([
+        ['alice', '@hubot give me a random number'],
+        ['hubot', '@alice 3'],
+        ['bob',   '@hubot give me a random number'],
+        ['hubot', '@bob 3']
+      ]);
+    });
+  });
+});
diff --git a/test/private-message_test.coffee b/test/private-message_test.coffee
deleted file mode 100644
index 09d8b48..0000000
--- a/test/private-message_test.coffee
+++ /dev/null
@@ -1,26 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/private-message.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'private-message', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'user asks hubot for a secret', ->
-    beforeEach ->
-      co =>
-        yield @room.user.say 'alice', '@hubot tell me a secret'
-
-    it 'should not post to the public channel', ->
-      expect(@room.messages).to.eql [
-        ['alice', '@hubot tell me a secret']
-      ]
-
-    it 'should private message user', ->
-      expect(@room.privateMessages).to.eql {
-        'alice': [
-          ['hubot', 'whisper whisper whisper']
-        ]
-      }
diff --git a/test/private-message_test.js b/test/private-message_test.js
new file mode 100644
index 0000000..cd4ba61
--- /dev/null
+++ b/test/private-message_test.js
@@ -0,0 +1,35 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/private-message.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('private-message', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('user asks hubot for a secret', function() {
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.say('alice', '@hubot tell me a secret');
+      }.bind(this));
+    });
+
+    it('should not post to the public channel', function() {
+      expect(this.room.messages).to.eql([
+        ['alice', '@hubot tell me a secret']
+      ]);
+    });
+
+    it('should private message user', function() {
+      expect(this.room.privateMessages).to.eql({
+        'alice': [
+          ['hubot', 'whisper whisper whisper']
+        ]
+      });
+    });
+  });
+});
diff --git a/test/scripts/bye.coffee b/test/scripts/bye.coffee
deleted file mode 100644
index a9f85cd..0000000
--- a/test/scripts/bye.coffee
+++ /dev/null
@@ -1,5 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.respond /bye$/i, (msg) ->
-    msg.reply 'bye'
diff --git a/test/scripts/bye.js b/test/scripts/bye.js
new file mode 100644
index 0000000..e160cba
--- /dev/null
+++ b/test/scripts/bye.js
@@ -0,0 +1,5 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.respond(/bye$/i, msg => msg.reply('bye'))
+;
diff --git a/test/scripts/custom-text-message.coffee b/test/scripts/custom-text-message.coffee
deleted file mode 100644
index 0908e4d..0000000
--- a/test/scripts/custom-text-message.coffee
+++ /dev/null
@@ -1,7 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.listen(
-    (message) -> message.isCustom
-    (response) -> response.send response.message.custom
-  )
diff --git a/test/scripts/custom-text-message.js b/test/scripts/custom-text-message.js
new file mode 100644
index 0000000..6c482ef
--- /dev/null
+++ b/test/scripts/custom-text-message.js
@@ -0,0 +1,7 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.listen(
+    message => message.isCustom,
+    response => response.send(response.message.custom))
+;
diff --git a/test/scripts/enter-leave.coffee b/test/scripts/enter-leave.coffee
deleted file mode 100644
index 840c9ce..0000000
--- a/test/scripts/enter-leave.coffee
+++ /dev/null
@@ -1,8 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.enter (res) ->
-    res.send "Hi #{res.message.user.name}!"
-
-  robot.leave (res) ->
-    res.send "Bye #{res.message.user.name}!"
diff --git a/test/scripts/enter-leave.js b/test/scripts/enter-leave.js
new file mode 100644
index 0000000..3f0f1c7
--- /dev/null
+++ b/test/scripts/enter-leave.js
@@ -0,0 +1,7 @@
+// Description:
+//   Test script
+module.exports = function(robot) {
+  robot.enter(res => res.send(`Hi ${res.message.user.name}!`));
+
+  return robot.leave(res => res.send(`Bye ${res.message.user.name}!`));
+};
diff --git a/test/scripts/events.coffee b/test/scripts/events.coffee
deleted file mode 100644
index 9b971c5..0000000
--- a/test/scripts/events.coffee
+++ /dev/null
@@ -1,9 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.on 'some-event', (some, data) ->
-    robot.messageRoom 'room1', "got event with #{some} #{data}"
-
-  robot.respond /send event$/i, (msg) ->
-    robot.emit 'response-event',
-      content: 'hello'
diff --git a/test/scripts/events.js b/test/scripts/events.js
new file mode 100644
index 0000000..e77ba88
--- /dev/null
+++ b/test/scripts/events.js
@@ -0,0 +1,7 @@
+// Description:
+//   Test script
+module.exports = function(robot) {
+  robot.on('some-event', (some, data) => robot.messageRoom('room1', `got event with ${some} ${data}`));
+
+  robot.respond(/send event$/i, msg => robot.emit('response-event', {content: 'hello'}));
+};
diff --git a/test/scripts/hello-world-listener.coffee b/test/scripts/hello-world-listener.coffee
deleted file mode 100644
index 0d73573..0000000
--- a/test/scripts/hello-world-listener.coffee
+++ /dev/null
@@ -1,9 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.listen(
-    (message) ->
-      message.user.name is 'bob'
-    (response) ->
-      response.reply 'hi'
-  )
diff --git a/test/scripts/hello-world-listener.js b/test/scripts/hello-world-listener.js
new file mode 100644
index 0000000..d513071
--- /dev/null
+++ b/test/scripts/hello-world-listener.js
@@ -0,0 +1,4 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.listen(message => message.user.name === 'bob', response => response.reply('hi'))
diff --git a/test/scripts/hello-world.js b/test/scripts/hello-world.js
new file mode 100644
index 0000000..67dce1d
--- /dev/null
+++ b/test/scripts/hello-world.js
@@ -0,0 +1,5 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.respond(/hi$/i, msg => msg.reply('hi'))
+;
diff --git a/test/scripts/httpd-world.coffee b/test/scripts/httpd-world.coffee
deleted file mode 100644
index 9e772a6..0000000
--- a/test/scripts/httpd-world.coffee
+++ /dev/null
@@ -1,5 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.router.get "/hello/world", (req, res) ->
-    res.status(200).send("Hello World!")
diff --git a/test/scripts/httpd-world.js b/test/scripts/httpd-world.js
new file mode 100644
index 0000000..2325990
--- /dev/null
+++ b/test/scripts/httpd-world.js
@@ -0,0 +1,5 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.router.get("/hello/world", (req, res) => res.status(200).send("Hello World!"))
+;
diff --git a/test/scripts/mock-response.coffee b/test/scripts/mock-response.coffee
deleted file mode 100644
index 0215b67..0000000
--- a/test/scripts/mock-response.coffee
+++ /dev/null
@@ -1,6 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.respond /give me a random number$/i, (msg) ->
-    randomNumber = msg.random [1, 2, 3, 4, 5]
-    msg.reply randomNumber
diff --git a/test/scripts/mock-response.js b/test/scripts/mock-response.js
new file mode 100644
index 0000000..cbb7679
--- /dev/null
+++ b/test/scripts/mock-response.js
@@ -0,0 +1,8 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.respond(/give me a random number$/i, function(msg) {
+    const randomNumber = msg.random([1, 2, 3, 4, 5]);
+    msg.reply(randomNumber);
+  })
+;
diff --git a/test/scripts/private-message.coffee b/test/scripts/private-message.coffee
deleted file mode 100644
index 5f0c64e..0000000
--- a/test/scripts/private-message.coffee
+++ /dev/null
@@ -1,5 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.respond /tell me a secret$/i, (msg) ->
-    msg.sendPrivate 'whisper whisper whisper'
diff --git a/test/scripts/private-message.js b/test/scripts/private-message.js
new file mode 100644
index 0000000..b73b1ff
--- /dev/null
+++ b/test/scripts/private-message.js
@@ -0,0 +1,5 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.respond(/tell me a secret$/i, msg => msg.sendPrivate('whisper whisper whisper'))
+;
diff --git a/test/scripts/user-params.coffee b/test/scripts/user-params.coffee
deleted file mode 100644
index 0eb6a98..0000000
--- a/test/scripts/user-params.coffee
+++ /dev/null
@@ -1,8 +0,0 @@
-# Description:
-#   Test script
-module.exports = (robot) ->
-  robot.listen(
-    () -> true
-    (response) ->
-      response.send JSON.stringify(response.message.user)
-  )
diff --git a/test/scripts/user-params.js b/test/scripts/user-params.js
new file mode 100644
index 0000000..db8eaee
--- /dev/null
+++ b/test/scripts/user-params.js
@@ -0,0 +1,7 @@
+// Description:
+//   Test script
+module.exports = robot =>
+  robot.listen(
+    () => true,
+    response => response.send(JSON.stringify(response.message.user)))
+;
diff --git a/test/user-params_test.coffee b/test/user-params_test.coffee
deleted file mode 100644
index d648adb..0000000
--- a/test/user-params_test.coffee
+++ /dev/null
@@ -1,22 +0,0 @@
-Helper = require('../src/index')
-helper = new Helper('./scripts/user-params.coffee')
-
-co     = require('co')
-expect = require('chai').expect
-
-describe 'enter-leave', ->
-  beforeEach ->
-    @room = helper.createRoom(httpd: false)
-
-  context 'user entering, leaving the room and sending a message', ->
-    params = { id: 1, name: 2, profile: 3 }
-    beforeEach ->
-      co =>
-        yield @room.user.enter 'user1', params
-        yield @room.user.say 'user1', 'Hi', params
-        yield @room.user.leave 'user1', params
-
-    it 'sends back', ->
-      for msg in @room.messages
-        if msg[0] is 'hubot'
-          expect(JSON.parse msg[1]).to.include(params)
diff --git a/test/user-params_test.js b/test/user-params_test.js
new file mode 100644
index 0000000..9aa221a
--- /dev/null
+++ b/test/user-params_test.js
@@ -0,0 +1,32 @@
+'use strict'
+
+const Helper = require('../src/index');
+const helper = new Helper('./scripts/user-params.js');
+
+const co     = require('co');
+const expect = require('chai').expect;
+
+describe('enter-leave', function() {
+  beforeEach(function() {
+    this.room = helper.createRoom({httpd: false});
+  });
+
+  context('user entering, leaving the room and sending a message', function() {
+    const params = { id: 1, name: 2, profile: 3 };
+    beforeEach(function() {
+      return co(function*() {
+        yield this.room.user.enter('user1', params);
+        yield this.room.user.say('user1', 'Hi', params);
+        yield this.room.user.leave('user1', params);
+      }.bind(this));
+    });
+
+    it('sends back', function() {
+      for (let msg of this.room.messages) {
+        if (msg[0] === 'hubot') {
+          expect(JSON.parse(msg[1])).to.include(params)
+        }
+      }
+    });
+  });
+});