var Fruit = function(color) {
  this.color = color;
  this.healthy = 'yes';
};
 
Fruit.prototype = {
  cutInPieces: function() {
    return Math.floor(Math.random()*11);
  }
};
 
var redFruit = new Fruit('red');
 
redFruit.color;
// 'red'
redFruit.healthy;
// 'yes'
redFruit.cutInPieces();
// 5
 
var stubbedRedFruit = smoking(redFruit, { healthy: 'a bit' });
 
stubbedRedFruit.healthy;
// 'a bit'
stubbedRedFruit.color;
// 'red'
stubbedRedFruit.cutInPieces();
// 2
redFruit.healthy;
// 'yes'
// You get the point

var uberChangedFruit = smoking(redFruit, {
  color: 'blue',
  cutInPieces: function() {
    return 7;
  }
});
 
uberChangedFruit.color;
// 'blue'
uberChangedFruit.cutInPieces();
// 7
uberChangedFruit.healthy;
// 'yes'

var mockFruit = smoking(redFruit).expects({ cutInPieces: 1 });
mockFruit.cutInPieces();
smoking(mockFruit).verify();

var mockFruit = smoking(redFruit).expects('cutInPieces');
smoking(mockFruit).verify();