Mock Socket

Javascript mocking library for websockets and socket.io

Installation

npm install mock-socket

Usage

To use within a node environment you can simply import or require the files directly. This option is great for phatomjs or CI environments.

var mockWebSocket = require('mock-socket').WebSocket;
var mockServer = require('mock-socket').Server;

// var socketIO = require('mock-socket').SocketIO;

To use within a browser environment you can include the bundled script file directly onto your page and reference the global objects from there.

<script src="./node_modules/mock-socket/dist/mock-socket.min.js"></script>
<script>
// window.MockServer
// window.MockWebSocket
// window.MockSocketIO
</script>

Native WebSocket Example

// chat.js
function Chat() {
  const chatSocket = new WebSocket('ws://localhost:8080');
  this.messages = [];

  chatSocket.onmessage = event => {
    this.messages.push(event.data);
  };
}

// chat-test.js
import { WebSocket, Server } from 'mock-socket';

describe('Chat Unit Test', function() {
  it('basic test', done => {
    const mockServer = new Server('ws://localhost:8080');
    mockServer.on('connection', server => {
      mockServer.send('test message 1');
      mockServer.send('test message 2');
    });

    /*
      This step is very important! It tells our chat app to use the mocked
      websocket object instead of the native one. The great thing
      about this is that our actual code did not need to change and
      thus is agnostic to how we test it.
    */
    window.WebSocket = WebSocket;

    // Now when Chat tries to do new WebSocket() it
    // will create a MockWebSocket object
    var chatApp = new Chat();

    setTimeout(() => {
      const messageLen = chatApp.messages.length;
      assert.equal(messageLen, 2, '2 messages where sent from the s server');
      done();
    }, 100);
  });
});

Socket.IO Example

// chat.js
function Chat() {
  const chatSocket = new io('http://localhost:8080');
  this.messages = [];

  socket.on('chat-message', data => {
    this.messages.push(data);
  };
}

// chat-test.js
import { SocketIO, Server } from 'mock-socket';

describe('Chat Unit Test', function() {
  it('basic test', done => {
    const mockServer = new Server('http://localhost:8080');
    mockServer.on('connection', server => {
      mockServer.emit('chat-message', 'test message 1');
      mockServer.emit('chat-message', 'test message 2');
    });

    /*
      This step is very important! It tells our chat app to use the mocked
      websocket object instead of the native one. The great thing
      about this is that our actual code did not need to change and
      thus is agnostic to how we test it.
    */
    window.io = SocketIO;

    // Now when Chat tries to do io() or io.connect()
    // it will use MockSocketIO object
    var chatApp = new Chat();

    setTimeout(() => {
      const messageLen = chatApp.messages.length;
      assert.equal(messageLen, 2, '2 messages where sent from the server');
      done();
    }, 100);
  });
});

Working with the source code

Local builds

The easiest way to work on the project is to clone the repo down via:

git clone git@github.com:thoov/mock-socket.git; cd mock-socket; npm i

Then to create a local build via:

npm run build

Then create a local npm link via:

npm link

At this point you can create other projects / apps locally and reference this local build via:

npm link mock-socket

from within your other projects folder. Make sure that after any changes you run npm run build!

Tests

This project uses mocha as its test framework. Tests are located in /test and have 1 of 3 file name prefixes (functional-, issue-#, or unit-). If you create a new test make sure that you add it to /test/helpers/test-loader.js.

npm test

Linting

This project uses eslint and a rules set from airbnb's javascript style guides. To run linting:

npm run lint

Code Coverage

Code coverage reports are created in /coverage after all of the tests have successfully passed.

Feedback / Issues

If you have any feedback, encounter any bugs, or just have a question, please feel free to create a github issue or send me a tweet at @thoov.