sinon mock object play

fun-with-sinon-mocks.js

/*jshint node:true */
'use strict';
var assert = require('assert');
var sinon = require('sinon');
var util = require('util');

function spew(label, o) {
  console.log(label, util.inspect(o, {colors:true, depth:null}));
}

function Class() {
  this.constructed = true;
}
Class.prototype.foo = function() {
  console.log('original foo', this, arguments);
  return 'foo';
};
Class.prototype.bar = function() {
  console.log('original bar', this, arguments);
  return 'bar';
};

function defaultNever(mock) {
  Object.keys(mock.object).forEach(function(property) {
    mock.expects(property).never();
  });
}

var mock = sinon.mock(Class.prototype);
defaultNever(mock);
spew('mock:', mock);
mock.foo = mock.expects('foo').never().once().returns('FOO');

spew('mocked prototype:', Class.prototype);

var instance = new Class();

try {
  var fooVal = instance.foo();
  console.log('fooVal', fooVal);
  assert.equal(fooVal, 'FOO');
} catch(e) {
  console.log('could not call foo', e);
}

try {
  var barVal = instance.bar();
  console.log('barVal', barVal);
} catch(e) {
  console.log('could not call bar', e);
}

try {
  mock.verify();
} catch(e) {
  console.log('verification:', e);
}

mock.restore();

spew('restored prototype:', Class.prototype);