I would like to write a test that verifies that a certain property will be saved using Mongoose, for instance:
var newUser = new userModel({
    id: /*something*/,
    gu: true
});
newUser.save(function (err, user) {
    /* ... */
    res.send(user.id);
});
In my tests, I want to make sure that the gu property is set to true. I can easily stub save(), however I can't verify that gu is set to true since save() is a function of the object and therefore it is not part of the parameters. Any ideas?