Using sinon.js to stub net.Socket and SocketStream pub/sub

net.Socket.stub.js

// Example test that stubs out node.js net.Socket.write() calls
// Using Mocha to drive: http://visionmedia.github.com/mocha/
// sinon.js for stubs/mocks/spies: http://sinonjs.org
// should.js for assertions: https://github.com/visionmedia/should.js

var sinon = require('sinon')
  , should = require('should')
  , net = require('net')

describe('Example Stubbing net.Socket', function() {
  
  it ("should stub net.Socket.write( ) and echo back what was written", function(done) {
    
    var socket = new net.Socket({});

    var stub = sinon.stub(socket, 'write', function (data, encoding, cb) {
      
      var args = stub.args;
      
      // this will echo whatever they wrote
      if (args.length > 0)
        this.emit('data', stub.args[stub.callCount - 1][0]);
    });

    socket.on('data', function(data) {
      data.should.eql('foo');
      // test is done or it will timeout and fail
      done();
    });

    socket.write('foo');
  });
});

SocketStream.publish.spy.js

// Example test that spies on SocketStream.publish.channel() calls
// Using Mocha to drive: http://visionmedia.github.com/mocha/
// sinon.js for stubs/mocks/spies: http://sinonjs.org
// should.js for assertions: https://github.com/visionmedia/should.js

var sinon = require('sinon')
  , should = require('should')
  , ss = require('socketstream').start();

describe("Spying on SocketStream for testing", function() {

  var spy;

  beforeEach( function(done) {
    spy = sinon.spy(ss.publish, 'channel');
    done();
  });

  afterEach( function(done) {
    spy.restore(ss.publish);
    spy.reset();
    done();
  });

  // here you'd be testing your code which triggers pub/sub
  // the spy allows you to assert that it was or was not triggered
  it("should allow me to spy on publish calls", function(done) {

    // publish foo event once
    ss.publish.channel('foo', 'fooEvent', 'fooMessage');
    ss.publish.channel.called.should.be.true;
    
    // publish bar event twice
    ss.publish.channel('bar', 'barEvent', 'barMessage');
    ss.publish.channel.calledTwice.should.be.true;
    ss.publish.channel('bar', 'barEvent2', 'barMessage');
    ss.publish.channel.calledThrice.should.be.true;

    ss.publish.channel.withArgs('foo').calledOnce.should.be.true;
    ss.publish.channel.withArgs('bar').calledTwice.should.be.true;
    done();  
  
  });
});