mocha stub using sinon in node.js - tdd

Question

I would like to know if I am missing anything with regard to sinon.js I have tried using sinon.stub().returns and yields but am unable to get the result. Any pointers would be helpful
I have a module which calls another module that returns the value from the DB
var users = require('/users');
module.exports.getProfileImage = function (req, res) {
var profile = {};
else {
users.findOne("email", req.session.user.email, function (err, user) {
if (err) {
res.status(400).send();
}
else if (!user) {
//return default image
}
else if (user) {
//Do some other logic here
}
});
};
I am using mocha as the testing framework and am also using sinon. The problem that I am facing is when i create a stub of users.findOne to return a value the control does not come to my else if (user) condition.
my unit test case is as follows
describe("Return image of user",function(){
var validRequest = null;
validRequest={
session:{
user:{
email:'testUser#test.com',
role:'Hiring Company'
}
}
};
it("Should return an image from the file if the user is present in db",function(done){
var findOneUserResponse ={
companyName:"xyz",
email:"xyz#abc.com"
};
var findOne = sinon.stub(mongoose.Model, "findOne");
findOne.callsArgWith(1,null,findOneUserResponse);
user.getProfileImage(validRequest,response);
var actualImage = response._getData();
findOne.restore();
done();
};
};

Answer 1

So I went through the sinon.js documentation http://sinonjs.org/docs/ and came across what I was missing
describe("Return image of user",function(){
var validRequest = null;
validRequest={
session:{
user:{
email:'testUser#test.com',
role:'Hiring Company'
}
}
};
it("Should return an image from the file if the user is present in db",function(done){
var findOneUserResponse ={
companyName:"xyz",
email:"xyz#abc.com"
};
var findOne = sinon.stub(mongoose.Model, "findOne",function(err,callback){
callback(null,findOneUserResponse);
)};
user.getProfileImage(validRequest,response);
var actualImage = response._getData();
findOne.restore();
done();
};
};